Multi-chassis broadcast router having a common clock

Multi-chassis broadcast router with common clock

This application relates to U.S. Provisional Patent Application No. 60/390,846 filed on June 21, 2002.

This application also involves the following simultaneous pending U.S. patent applications: PCT/ (agent case number IU010620), PCT/(agent case number IU020157), PCT/(agent case number IU020158), PCT/ (Agent case number IU020159), PCT/(Agent case number IU020160), PCT/(Agent case number IU020161), PCT/(Agent case number IU020162), PCT/(Agent case number IU020252 ), PCT/(Agent case number IU020254), PCT/(Agent case number IU020255) and PCT/(Agent case number IU020256), all of these applications are assigned to the assignee of this application, hereby in full text Quote for reference.

Technical field

The invention relates to a broadcast router, in particular to a multi-chassis broadcast router with a common clock.

Background technique

The broadcast router is such that each of its multiple outputs is assigned a signal from any one of the multiple inputs that reach the broadcast router. For example, an N×M broadcast router contains N input terminals and M output terminals. These N input terminals and M output terminals are coupled in a routing matrix by applying any one of the N input terminals to each of the M output terminals. together. Many of these broadcast routers consist of a single rack encapsulating multiple printed circuit boards (often called "cards"), which are connected to each other in a variety of configurations. Oftentimes, by connecting multiple printed circuit boards to each other. A small broadcast router is used to construct a larger broadcast router. For example, in the U.S. patent application with serial number 10/__ (Attorney Docket No. IU020160) previously incorporated as a reference, it is disclosed that five 256 ×256 broadcast routers are fully redundant and linearly expandable 1,280×1,280 broadcast routers. However, in order to implement the multi-chassis broadcasting router disclosed in that application, the same clock must be obtained in each chassis.

Summary of the invention

In one embodiment, the present invention relates to a multi-chassis broadcast router including a plurality of chassis, in each chassis there is a routing engine and at least one clock demand component. Also, what exists in the first of the multiple racks is a master clock coupled to a clock demand component existing in each rack of the broadcast router. Preferably, the input end of each routing engine of the broadcast router is coupled to the other input end in a fully connected topology through multiple links, and the multiple links are also used to transfer the common clock signal from the master clock. Allocate to all clock requirements components.

In another embodiment, the present invention relates to a multi-chassis broadcast router including first and second chassis. Each rack can support the installation of a first router matrix card, a redundant router matrix card, at least one clock demand input card, and at least one clock demand input card. The first master clock exists on the first router matrix card that can be installed by the first rack, and the second master clock exists on the redundant router matrix card that can be installed by the second rack. Each master clock is coupled to each clock demand input and output card that can be installed supported by the first rack, and to each clock demand input and output card that can be installed supported by the second rack. The first master clock provides the common clock signal to the clock demand card coupled to it, and when there is no common clock signal, the second master clock provides the redundant common clock signal to the clock demand card coupled to it. The control logic circuit coupled to the first and second master clocks determines whether the first master clock will issue a common clock signal, or whether the second master clock will issue a redundant common clock signal when there is no common clock signal.

Description of the drawings

Figure 1 is a block diagram of a fully redundant linearly scalable broadcast router; Figure 2 is an enlarged block diagram of the first broadcast router component of the fully redundant linearly scalable broadcast router of Figure 1; Figure 3 is a fully redundant linearly scalable broadcast router of Figure 1 An enlarged block diagram of the second broadcast router component of the broadcast router; FIG. 4 is a state diagram of the state machine of the first broadcast router component of FIG. 2; and FIG. 5 is a state diagram of the state machine of the second broadcast router component of FIG. 4.

detailed description

Referring first to FIG. 1, a multi-chassis broadcast router 100 constructed according to an aspect of the principles of the present invention will now be described in more detail, and each chassis shares a common clock. As disclosed herein, the broadcast router 100 is a fully redundant linearly scalable broadcast router. However, it should be clearly recognized that it is entirely conceivable that other types of multi-chassis broadcast routers other than the specific type of multi-chassis broadcast routers disclosed herein may also be configured to share a common clock. It should also be recognized that the teachings of the present invention are equally applicable to broadcast routers configured to include multiple broadcast router components packaged in a common rack.

As can be seen now, the multi-rack fully redundant linearly scalable broadcast router 100 includes multiple broadcast router components, each of which is packaged in its own rack and coupled with each other to form a larger fully redundant linearly scalable Broadcast router 100. Each broadcast router component is a separate router component that includes a first (or "primary") router matrix card and a second (or "redundant") router matrix card. Therefore, each broadcast router component has first and second routing engines, each engine being present on each of the first and redundant router matrix cards. As will be described more fully below, each of the first and second routing engines during the broadcast router receives the same N input digital audio data streams at its input and the same M outputs at its output Digital audio data stream. As disclosed here, the linearly scalable broadcast router is a broadcast router with a size of N×M. However, it is entirely conceivable that the multi-chassis fully redundant linearly expandable broadcast router 100 can be constructed instead of broadcast router components of different sizes.

As further disclosed herein, the first, second, third, and fourth broadcast router components 102, 104, 106, and 108 are coupled together to form a multi-chassis fully redundant linearly scalable broadcast router 100, the first Each of the second, third, and fourth broadcast router components are packaged in separate racks. Of course, the currently disclosed multi-chassis fully redundant linearly scalable broadcast router 100 is composed of four broadcast router components 102, 104, 106, and 108, purely as an example. Therefore, it should be clearly recognized that the multi-chassis fully redundant linearly scalable broadcast router 100 constructed in accordance with the principles of the present invention can be formed by using various other numbers of broadcast router components. As can be seen in Figure 1, when all connected in the manner disclosed herein, the first, second, third and fourth broadcast router components 102, 104 of the multi-chassis fully redundant linearly scalable broadcast router 100 are collectively formed. , 106 and 108 are packaged in their respective racks. Or, of course, the first, second, third, and fourth broadcast router components 102, 104, 106, and 108 may be packaged together in a common rack instead. Also, although as previously described, each of the first, second, third, and fourth broadcast router components 102, 104, 106, and 108 may have different sizes from each other, or alternatively, may all have the same N×M size, but the size that has proved suitable for the use envisaged here is 256×256. Finally, the appropriate configuration of the multi-chassis fully redundant linearly scalable broadcast router 100 will be able to couple 5 broadcast router components each 256×256 in size and encapsulated in separate racks, resulting in a 1,280×1,280 broadcast router.

The first broadcast router component 102 of the multi-rack fully redundant linearly expandable broadcast router 100 includes a rack 102C, and the first router matrix card 102A and the redundant router matrix card 102B can be installed in the rack 102C. The redundant router matrix card 102B is used to replace the first router matrix card 102A when the first router matrix card 102A fails. Similarly, the second broadcast router component 104 of the multi-chassis fully redundant linearly expandable broadcast router 100 includes a chassis 104C, and the first router matrix card 104A and the redundant router matrix card 104B can be installed in the chassis 104C. , The redundant router matrix card 104B is used to replace the first router matrix card 104A when the first router matrix card 104A fails; the third broadcast router component 106 of the multi-chassis fully redundant linear scalable broadcast router 100 It includes a rack 106C, in which a first router matrix card 106A and a redundant router matrix card 106B can be installed, and the redundant router matrix card 106B is used in the event that the first router matrix card 106A fails The first router matrix card 106A is replaced below; and the fourth broadcast router component 108 of the multi-chassis fully redundant linearly expandable broadcast router 100 includes a chassis 108C, and the first router matrix card 108A can be installed in the chassis 108C. And a redundant router matrix card 108B, the redundant router matrix card 108B is used to replace the first router matrix card 108A when the first router matrix card 108A fails. Of course, in the event that the router matrix cards 102A, 104A, 106A, and 108A fail, each router matrix card 102B, 104B, 106B, and 108B is designated as the spare redundancy of the router matrix cards 102A, 104A, 106A, and 108A, respectively. The matrix card is purely arbitrary, and it is completely conceivable that any router matrix card pair existing in the broadcast router component can be used as a backup for other router matrix pairs existing in the broadcast router component.

Although each of the broadcast router components 102, 104, 106, and 108 includes first and redundant router matrix cards as will be described more fully below, the first router matrix card of the broadcast router component may be the same as the broadcast router component. The redundant router matrix cards are basically the same or different. Specifically, for the first broadcast router component 102, the structure of the first router matrix card 102A is different from the redundant router matrix card 102B. Similarly, for the second broadcast router component 104, the structure of the first router matrix card 104A is different from the redundant router matrix card 104B. For the third and fourth broadcast router components, the first router matrix cards 106A and 108A are basically the same as the redundant router matrix cards 106B and 108B, respectively. However, it should be noted that the routing engine existing on the first router matrix card is basically the same as the routing engine existing on the redundant router matrix card.

As can be further understood in FIG. 1, the first router matrix card 102A of the first broadcast router component 102, the first router matrix card 104A of the second broadcast router component 104, and the first router matrix card of the third broadcast router component 106 106A and the first router matrix card 108A of the fourth broadcast router component 108 are coupled together into the first configuration of the router matrix card conforming to the fully connected topology. Similarly, the redundant router matrix card 102B of the first broadcast router component 102, the redundant router matrix card 104B of the second broadcast router component 104, the redundant router matrix card 106B of the third broadcast router component 106, and the fourth broadcast router The redundant router matrix cards 108B of the component 108 are coupled together into a second configuration similar to the first configuration that conforms to a fully connected topology. In a fully connected topology, each router matrix card in the configuration of router matrix cards is coupled to each and all other router matrix cards that form a partial configuration of router matrix cards through separate links.

Therefore, for the first configuration of the router matrix card, the first, second, and third bidirectional links 110, 112, and 114 couple the first router matrix card 102A existing in the rack 102C of the first broadcast router component 102, respectively To the first router matrix card 104A that exists in the rack 104C of the second broadcast router component 104, the first router matrix card 106A that exists in the rack 106C of the third broadcast router component 106, and the fourth broadcast router The first router matrix card 108A in the rack 108C of the component 108. In addition, the fourth and fifth bidirectional links 116 and 118 couple the first router matrix card 104A existing in the rack 104C of the second broadcast router component 104 to the rack 106C existing in the third broadcast router component 106, respectively. The first router matrix card 106A and the first router matrix card 108A existing in the rack 108C of the fourth broadcast router component 108. Finally, the sixth bidirectional link 120 couples the first router matrix card 106A present in the rack 106C of the third broadcast router component 106 to the first router matrix card 106A present in the rack 108C of the fourth broadcast router component 108 108A.

Similarly, for the second configuration of the router matrix card, the first, second, and third bidirectional links 122, 124, and 126 will exist in the redundant router matrix card 102B in the rack 102C of the first broadcast router component 102, respectively. Coupled to the redundant router matrix card 104B that exists in the rack 104C of the second broadcast router component 104, the redundant router matrix card 106B that exists in the rack 106C of the third broadcast router component 106, and the redundant router matrix card 106B that exists in the fourth broadcast router component 106 The redundant router matrix card 108B in the rack 108C of the router component 108. In addition, the fourth and fifth bidirectional links 128 and 130 respectively couple the redundant router matrix card 104B existing in the rack 104C of the second broadcast router component 104 to the rack 106C existing in the third broadcast router component 106 The redundant router matrix card 106B and the redundant router matrix card 108B existing in the rack 108C of the fourth broadcast router component 108. Finally, the sixth bidirectional link 132 couples the redundant router matrix card 106B existing in the rack 106C of the third broadcast router component 106 to the redundant router matrix card existing in the rack 108C of the fourth broadcast router component 108 108B.

The first, second, third, and fourth broadcast router components 102, 104, 106, and 108 will now be described in more detail. FIG. 2 shows the first broadcast router component 102. As previously explained, the first broadcast router component 102 includes a first router matrix card 102A and a redundant router matrix card 102B, which can be slidably accommodated by the rack 102C (not shown in FIG. 2) of the first broadcast router component 102 And can support the installation of each of the first router matrix card 102A and the redundant router matrix card 102B. The rack 102 can also slidably accommodate and support the installation of input cards 136-1 to 136-N and output cards 138-1 to 138-M. Each input card 136-1 to 136-N is coupled to the first router matrix card 102A and the redundant router matrix card 102B. Likewise, each output card 138-1 to 138-M is coupled to the first router matrix card 102A and the redundant router matrix card 102B. Of course, although the discrete input and output cards 136-1 to 136-N and 138-1 to 138-M are shown in FIG. 2, it needs to be clearly understood that, if necessary, there are input and output cards (for example, The functions on the input card 136-1 and output card 138-1) can be replaced on separate input/output ("I/O") cards. In addition, although FIG. 2 shows discrete input and output cards 136-1 to 136-N and 138-1 to 138-M, it is entirely conceivable that, depending on the available space thereon, there are input cards (for example, input card 136-1), all or part of the functions on the output card (for example, output card 138-1), or on the input card and output card (for example, input card 136-1 and output card 138-1) can be changed to exist in the first A router matrix card 102A, a redundant router matrix card 102B, or some combination of them.

An input signal selection circuit (not shown) is present on each input card 136-1 to 136-N. The input signal selection circuit selects an input signal from a plurality of input signals it receives, and sends it to the first router matrix card 102A and the redundant router matrix card 102B. Generally, the input signal selection circuit is used to input digital audio data streams that comply with the American Society of Acoustic Engineering-11 ("AES-11") standard and the multi-channel digital audio interface ("MADI") specified in the AES-10 standard. Choose between standard input digital audio data streams. At this point, it should be noted that the MADI input digital audio data stream can contain up to 32 AES digital audio data streams, and each input to the input selection circuit should typically contain a single AES digital audio data stream, which has been previously passed The extraction circuit (not shown) extracts the single AES digital audio data stream from the MADI input digital audio data stream. Of course, such a configuration is purely an example, and it is entirely conceivable that if the first broadcast router component 102 is replaced with a configuration to receive a single type of digital audio data as its input, no input signal selection circuit is required.

Since the input selection circuit present on each input card 136-1 to 136-N selects the input digital audio stream to be sent to each of the first and redundant router matrix cards 102A and 102B, each of the first and redundant router matrix cards 102A and 102B The router matrix cards 102A and 102B receive input digital audio signals 1 to N from the input cards 136-1 to 136-N, respectively. The routing engine ("RE") 140, the transmission expansion port ("EXP") 146, the first, second and third reception expansion ports (not shown), the first master clock ("CLK-A") 134 and the first A state machine ("SM") 148 exists on the first router matrix card 102A. The input digital audio streams 1 to N propagated from the input cards 136-1 to 136-N are sent to the routing engine 140 and the sending expansion port 146. The operation of the routing engine 140 and the sending expansion port 146 is described in more detail in the pending US patent application while the serial number previously incorporated as a reference is 10/__ (Attorney Docket No. IU020160). However, in simple terms, the N input digital audio data streams received by the transmission expansion port 146 are forwarded to the first router matrix card 104A of the second router matrix component 104 and the first router matrix card 106A of the third router matrix component 106. , And the first router matrix card 108A of the fourth router matrix component 108. Similarly, the router matrix cards 104A, 106A, and 108A have transmission expansion ports that send the input digital audio data streams N+1 to 2N, 2N+1 to 3N, and 3N+1 to 4N respectively received by them to The routing engine 140.

The input digital audio streams 1 to N output from the input cards 136-1 to 136-N and the input digital audio data streams N+1 to 2N respectively received from the second, third, and fourth broadcast router parts 104, 106, and 108 , 2N+1 to 3N, and 3N+1 to 4N are provided as inputs to the routing engine 140 together. The signal selection function present on the routing engine 140 can connect each of the M outputs to one input selected from 4N inputs. The selection of a specific input among the 4N inputs connected to each of the M outputs is controlled by a control circuit (also not shown). From the routing engine 140, each of the M output digital audio data streams is transmitted to a corresponding output card of the output cards 138-1 to 138-M. Existing on each of the output cards 138-1 to 138-M is an output signal selection circuit (not shown), the output signal selection circuit from the first output digital audio data stream received by the first router matrix card 102A and Among the second output digital audio data streams received by the second router matrix card 102B, the digital audio data stream to be output to the first broadcast router component 102 is selected.

As previously explained, the first master clock 134 and the first state machine 148 also exist on the first router matrix card 102A of the first broadcast router component 102. As will be described more fully below, the first master clock 134 provides a first common clock signal to all clock demand components of the broadcast router 100. As disclosed herein, the input and output cards of each broadcast router component 102, 104, 106, and 108 are designated as clock demand components. However, the above disclosure is purely an example, and it is entirely conceivable that other components (including components shown in the drawings and/or components omitted to simplify the description) may also be clock-required components. Therefore, the first common clock signal generated by the first master clock 134 is bound to the clock input CLK-A of each of the input cards 136-1 to 136-N and the output cards 138-1 to 138-M. If the first common clock signal generated by the first master clock 134 is bound to the clock input CLK-A of each input card 142-1 to 142-N and output card 144-1 to 144-M, the link 110 will The first common clock is also sent to the second broadcast router component 104. Using various techniques, it is also conceivable to distribute the first common clock signal generated by the first master clock 134 to other broadcast router components, for example, the broadcast router component 104. If the first common clock signal CLK-A is added to the data signal, the first master clock preferably sends the first common clock signal CLK-A to the sending expansion port 146, wherein the data signal is sent to the presence via the link 110 The receiving expansion port on the first router matrix card 104A. Once the data signal reaches the first router matrix card 104A, the first common clock signal CLK-A is extracted from the data signal for subsequent distribution to the clock demand components of the first router matrix card 104A. Or it is envisaged that the first common clock signal CLK-A can be transmitted through the link 110 using discrete wires (for example, conductive wires or optical fibers), so as to form a link 110 by adding one wire to one or more individually or collectively. There are lines (for example, a line for transmitting the first common clock signal and a line for transmitting the digital audio data signal are wound from the transmission expansion port 146 to the second broadcast router component 104), thereby exclusively transmitting the first common clock signal. In a similar manner, the output of the first master clock 134 is sent to the third and fourth broadcast router components 106 and 108 via links 112 and 114, respectively, so that the first common clock signal is also distributed to all input and output cards .

The first master clock 134 is controlled by the first state machine 148. It can be further understood in FIG. 2 that the state machine 148 has a first input terminal coupled to the routing engine 140, a second input terminal coupled to the transmission expansion port 146, and a redundant routing matrix existing in the second broadcast router component 104. The third input terminal of the routing engine 150 of the card 104B, the fourth input terminal coupled to the transmission expansion port 152 of the redundant routing matrix card 104B present in the second broadcast router component 104, and the output coupled to the first master clock 134 end. As described herein, the third and fourth inputs of the second router matrix card 104B starting from the second broadcast router component 104 are coupled to the state machine 148 via links 110 and 122, respectively. However, it is entirely conceivable that the third and fourth input terminals can be coupled to the state machine 148 through other links instead, and if necessary, the two input terminals can also be coupled to the state through the link 110 or the link 122.machine148. In addition, although the specific details of the operation of the state machine 148 are described more fully below, in brief, the first state machine 148 is based on the routing engine 140 coupled to its first, second, third, and fourth inputs. The operating conditions of the sending expansion port 146, the routing engine 150, and the sending expansion port 152, selectively starting/stopping the first master clock 134.

Among the four components of the first router matrix card 102A shown in FIG. 2, the redundant router matrix card 102B only includes a transmission expansion port (not shown) and a routing engine (also not shown), and the transmission expansion port is The coupling is used to receive digital audio data input signals 1 to N from the input cards 136-1 to 136-N, and the routing engine is coupled to receive digital audio data signals 1 to N from the input cards 136-1 to 136-N , Receive digital audio data signals N+1 to 23N from the redundant router matrix card 104B through the link 122, receive digital audio data signals 2N+1 to 3N from the redundant router matrix card 106B through the link 124, and through the link 126 The digital audio data signals 3N+1 to 4N are received from the redundant router matrix card 108B. The routing engine further includes M output terminals respectively coupled to the output cards 1 to M. The signal selection function existing in the routing engine connects each of the M output terminals to an input terminal selected from 4N input terminals. The same control is performed on the routing engine 140 existing on the first router matrix card 102A and the routing engine existing on the redundant router matrix card 102B, so that the M output digital audio data streams of the first router matrix card 102A and the redundant router The M output digital audio data streams of the matrix card 102B are the same.

FIG. 3 shows the second broadcast router component 104. As previously explained, the second broadcast router component 104 includes a first router matrix card 104A and a redundant router matrix card 104B, and is slidable in the rack 104C (not shown in FIG. 3) of the second broadcast router component 104 Accommodate and support the installation of each of the first router matrix card 104A and the redundant router matrix card 104B. The rack 104 can also be slidably accommodated and can support the installation of input cards 142-1 to 142-N and output cards 144-1 to 144-M. Each input card 142-1 to 142-N is coupled to the first router matrix card 104A and the redundant router matrix card 104B. Likewise, each output card 144-1 to 144-M is coupled to the first router matrix card 104A and the redundant router matrix card 104B. Of course, shown in FIG. 3 are discrete input and output cards 142-1 to 142-N and 144-1 to 144-M, but it should be clearly understood that, if necessary, there are input and output cards. (For example, the functions on the input card 142-1 and the output card 144-1) can also be changed to exist on separate I/O cards. In addition, although Figure 3 shows discrete input and digital cards 142-1 to 142-N and 144-1 to 144-M, it is entirely conceivable that, depending on the available space thereon, the illustration is shown as being present in the input All or part of the functions on the card (such as the input card 142-1), the output card (such as the output card 144-1), or both can be changed to exist in the first router matrix card 104A, the redundant router matrix card 104B or Some of them are combined.

Existing on each of the input cards 142-1 to 142-N is an input signal selection circuit (not shown). The input signal selection circuit selects input signals to be transmitted to both the first router matrix card 104A and the redundant router matrix card 104B from the plurality of input signals it receives. Generally, the input selection circuit is used to select between an input digital audio data stream conforming to the AES-11 standard and an input digital audio data stream conforming to the MADI standard specified in the AES-10 standard. It should be noted again at this point that the MADI input digital audio data stream can contain a 32AES-compliant digital audio data stream, and each input to the input selection circuit should typically contain a separate AES digital audio data stream, which has been previously passed An extraction circuit (also not shown) extracts the separate AES digital audio data stream from the MADI input digital audio data stream. Of course, such a configuration is purely an example, and it is entirely conceivable that multiple of N+1 to 2N input digital audio data streams can be received from a single input card 142-1 to 142-N.

Since the input selection circuit existing on each input card 142-1 to 142-N selects the input digital audio data stream to be sent to each of the first and redundant router matrix cards 104A and 104B, each of the first and redundant router matrix cards 104A and 104B The remaining router matrix cards 104A and 104B receive input digital audio signals N+1 to 2N from the input cards 142-1 to 142-N, respectively. The routing engine 150, the transmission expansion port 152, the first, second and third reception expansion ports (not shown), the second master clock ("CLK-B") 154 and the state machine 156 exist in the redundant router matrix card 104A on. The input digital audio streams N+1 to 2N respectively propagated from the input cards 142-1 to 142-N are sent to the routing engine 150 and the sending expansion port 152. As previously recorded, the operation of the routing engine 150 and the sending expansion port 152 is described in more detail in the pending US patent application while the serial number previously cited as a reference in its entirety is 10/___ (Attorney Docket No. IU020160) . However, in simple terms, the input digital audio data stream N+1 to 2N received by the sending expansion port 152 is sent to the redundant router matrix card 102B of the first router matrix component 102 and the redundant router of the third router matrix component 106 The matrix card 106B and the redundant router matrix card 108B of the fourth router matrix component 108. Similarly, the router matrix cards 102B, 106B, and 108B have transmission expansion ports that send the input digital audio data streams 1 to N, 2N+1 to 3N, and 3N+1 to 4N respectively received by them to the routing engine 150.

N+1 to 2N input digital audio streams transmitted from input cards 142-1 to 142-N and input digital audio data streams received from the first, third, and fourth broadcast router components 102, 106, and 108, respectively 1 To N, 2N+1 to 3N, and 3N+1 to 4N are provided together as inputs to the routing engine 150. The signal selection function present on the routing engine 150 can connect each of the M outputs to one input selected from 4N inputs. The selection of a specific input among the 4N inputs connected to each of the M outputs is controlled by a control circuit (also not shown). From the routing engine 150, each of the M output digital audio data streams is propagated to a corresponding output card among the output cards 144-1 to 144-M. Existing on each of the output cards 144-1 to 144-M is an output signal selection circuit (not shown) that receives the first output digital audio data stream from the first router matrix card 104A and From the second output digital audio data stream received from the second router matrix card 104B, the digital audio data stream to be output to the second broadcast router component 104 is selected.

As previously explained, the second master clock 154 and the first state machine 156 also exist on the second router matrix card 104B of the second broadcast router component 104. As will be described more fully below, the second master clock 154 provides a second (redundant) common clock signal to all clock demand components of the broadcast router 100. Therefore, the output of the second master clock 154 is bound to the clock input CLK-B of each of the input cards 142-1 to 142-N and the output cards 144-1 to 144-M. If the output of the second master clock 154 is bound to the clock input CLK-B of each input card 136-1 to 136-N and output card 138-1 to 138-M, the output is also connected through the link 122 Send to the first broadcast router component 102. If the second common clock signal CLK-B is added to the data signal, the second master clock preferably sends the second common clock signal CLK-B to the sending expansion port 152, wherein the data signal is sent to the existing The receiving expansion port on the first router matrix card 102A. Once the data signal reaches the first router matrix card 102A, the second common clock signal CLK-B is extracted from the data signal for subsequent distribution to the clock demand components of the first router matrix card 102A. Or it is envisaged that the second common clock signal CLK-B can be transmitted through the link 124 using discrete wires (for example, conductive wires or optical fibers), so as to form a link 124 by adding one wire to one or more individually or collectively. There are lines (for example, lines that transmit the first common clock signal and lines that transmit digital audio data signals N+1 to 2N are wound from the transmission expansion port 152 to the first broadcast router component 104), thereby exclusively transmitting the second common clock signal . Similarly, the output of the second master clock 154 is also sent to the third and fourth broadcast router components 106 and 108 via the links 128 and 130, so as to also distribute the second common clock signal to all input and output cards. Of course, although FIG. 3 shows that only the input and output cards are used as clock-required components, it is entirely conceivable that other components of the second broadcast router component 104 shown in FIG. 3, and those omitted in FIG. 3 to simplify the description The components of the second broadcast router component 104 may all be clock demand components having a CLK-B input coupled to the second master clock 154. However, it should be kept in mind that all the clock requirement components of the multi-chassis fully redundant linear scalable broadcast router 100 should include the components coupled to the first master clock 134 and the second master clock respectively.

The second master clock 154 is controlled by the state machine 156. It can be further understood in FIG. 3 that the state machine 156 has a first input terminal coupled to the routing engine 150, a second input terminal coupled to the transmission expansion port 152, and a first routing matrix existing in the first broadcast router component 102. The third input terminal of the routing engine 140 on the card 102A, the fourth input terminal coupled to the transmission expansion port 146 of the first routing matrix card 102A existing in the first broadcast router component 102, and the fourth input terminal coupled to the second master clock 154 The output terminal. As described herein, the third and fourth inputs of the first router matrix card 102A starting from the first broadcast router component 102 are coupled to the state machine 156 via links 122 and 110, respectively. However, it is entirely conceivable that the third and fourth input terminals can be coupled to the state machine 156 through other links instead, and if necessary, the two input terminals can also be coupled to the state through the link 110 or the link 122.machine156. In addition, although the specific details of the operation of the state machine 156 are described more fully below, in brief, the state machine 156 is based on the routing engine 150, the sending expansion port 152, the routing engine 140, and the sending expansion port 146 to which it is coupled. Operating conditions, selectively start/stop the second master clock 154.

Among the four components of the redundant router matrix card 104B shown in FIG. 3, the first router matrix card 104A only includes a transmission expansion port (not shown) and a routing engine (also not shown), and the transmission expansion port is The coupling is used to receive digital audio data input signals N+1 to 2N from the input cards 142-1 to 142-N, and the routing engine is coupled to receive digital audio data signals N from the input cards 142-1 to 142-N +1 to 2N, receiving digital audio data signals 1 to N from the first router matrix card 102A through the link 110, receiving digital audio signals 2N+1 to 3N from the first router matrix card 106A through the link 116, and through the link 118 receives digital audio signals 3N+1 to 4N from the first router matrix card 108A. The routing engine further includes M output terminals respectively coupled to the output cards 1 to M. The signal selection function existing in the routing engine connects each of the M output terminals to an input terminal selected from 4N input terminals. The same control is performed on the routing engine 150 existing on the redundant router matrix card 104B and the first engine existing on the first router matrix card 104A, so that the M output digital audio data streams of the first router matrix card 104A and the redundant The M output digital audio data streams of the remaining router matrix card 104B are the same.

The third and fourth broadcast router components 106 and 108 are approximately the same as each other, and slightly similar to the first and second broadcast router components 102 and 104. As previously explained, the third broadcast router component 106 includes a first router matrix card 106A and a redundant router matrix card 106B, which can be slidably accommodated or supported to install the first router matrix card 106A and redundant router matrix card through the rack 106C. Each of 106B. Similarly, the fourth broadcast router component 108 includes a first router matrix card 108A and a redundant router matrix card 108B, which can be slidably accommodated or supported to be installed in the first router matrix card 108A and the redundant router matrix card 108B through the rack 108C Of each. Similarly, the first and redundant router matrix cards 106A and 106B of the third broadcast router part 106, and the first and redundant router matrix cards 108A and 108B of the fourth broadcast router part 108 are substantially the same as the first broadcast router. The redundant router matrix card 102B of the router component 102 and/or the first router matrix card 104A of the second broadcast router component 104. In other words, the first router matrix cards 106A and 108A and the redundant router matrix cards 106B and 108B both include a transmitting expansion port, a routing engine, and a plurality of receiving expansion ports, but do not include a master clock and a state machine.

Each of the third and fourth broadcast router components 106 and 108 further includes N input cards and M output cards, and all input cards and input cards can be slidably accommodated and supported by the racks 106C and 108C, respectively. Each input and output card of the third broadcast router component 106 is coupled to each first router matrix card 106A and redundant router matrix card 106B. Likewise, each input and output card of the fourth broadcast router component 108 is coupled to each first router matrix card 108A and redundant router matrix card 108B. Similar to the input and output cards of the first and second broadcast router components 102 and 104, each of the input and output cards of the third and fourth broadcast router components 106 and 108 includes a first and second master clock 134, respectively. And CLK-A input and CLK-B input of 154. More specifically, the input and output cards of the third broadcast router component 106 are bound to the first master clock 134 through the link 112 and are bound to the second master clock 154 through the link 128, and through the link 114 binds the input and output cards of the fourth broadcast router component 108 to the first master clock 134 and binds it to the second master clock 154 through the link 130.

As previously explained, the clock demand components that exist on each rack 102C, 104C, 106C, and 108C of the multi-rack broadcast router 100 are coupled to receive a common clock signal, for example, generated by the first master clock 134 CLK-A signal. The clock demand components existing on each rack 102C, 104C, 106C, and 108C of the multi-rack broadcast router 100 are further coupled to receive redundant common clock signals, for example, the CLK- generated by the first master clock 154 B signal. However, the redundancy should be handled in the following manner: the invalidation of any router matrix card (for example, the router matrix card 102A) or any rack (for example, the rack 104B) can not cause the invalidation of the entire broadcast router 100. Table I below shows the logic executed to achieve this result. The router matrix card of the broadcast router component used in the following Table I is regarded as "OK" when it not only exists but also operates the router matrix card. In addition, when the frequency of the clock signal received from the master clock with the transmission expansion port existing on the router matrix card is relatively stable, the transmission expansion port is shown as "locked".

Table I. As previously explained, by performing common clock signal redundancy according to the requirements listed in Table I, any router matrix card (such as router matrix card 102A) or any rack (such as chassis 104B) can be invalidated. It does not cause the invalidation of the entire broadcast router 100. More specifically, if the first broadcast router 102 works normally, that is, the router matrix card 102 is ready and the transmission expansion port 146 is locked, the first master clock 134 distributes the clock signal CLK-A as a common clock signal to the multiple The rack broadcasts all the clock required components of the router 100, so that the multi-rack broadcast router 100 can operate in a full state. However, if the first router matrix card 102A is invalid because the transmission expansion port 146 is not locked, although the first master clock can still generate the clock signal CLK-A, it cannot distribute the clock signal to the entire multi-rack broadcast router 100. In this case, if the redundant router matrix card 104B is ready and the transmission expansion port 152 is locked, the second master clock 154 can distribute the clock signal CLK-B as a common clock signal to all of the multi-rack router 100 The clock requires components so that the multi-chassis broadcast router 100 can continue to operate in a full state. Similarly, if the first router matrix card 102 is invalid, for example, if the first router matrix card 102A is lost, the first master clock 134 will not be able to provide the clock signal CLK-A. In this case, if the redundant router matrix card 104B is ready and the transmission expansion port 152 is locked, regardless of whether the transmission expansion port 146 is locked, the second master clock 154 can use the clock signal CLK-B as a common clock signal again. All clock requirements components allocated to the multi-rack router 100, so that the multi-rack broadcast router 100 can continue to operate in a full state.

If the first router matrix card 102A is ready and neither the sending expansion port 146 nor the sending expansion port 152 is locked, the first master clock 134 will become the master clock of the multi-rack broadcast router 100. Although the first master clock 134 can still generate the clock signal CLK-A, the clock signal CLK-A cannot be distributed to other racks of the multi-rack broadcast router 100. Since only the clock demand components of the broadcast router component 102 will have a common clock signal, the multi-chassis broadcast router 100 will operate in a partial state. On the other hand, if the first router matrix card 102A is invalid, the redundant router matrix card 104B is still ready, and the transmission expansion port 152 is not locked, the second master clock 154 will become the master clock of the multi-chassis broadcast router 100. Although the second master clock 154 can still generate the clock signal CLK-B, the clock signal CLK-B cannot be distributed to other racks of the multi-rack broadcast router 100. Since only the clock demand components of the broadcast router component 104 will have a common clock signal, the multi-chassis broadcast router 100 will operate in a partial state again. Finally, if both the first router matrix card 102A and the redundant router matrix card 104B are invalid, the multi-chassis broadcast router will not have a master clock. Since there is no common clock signal that can be provided to the clock demand components of the multi-chassis broadcast router 100, the multi-chassis broadcast router 100 will be completely invalid.

Use Boolean logic to execute Table I above. However, in doing so, undesirable behavior will occur. It is best to ensure that the removal and insertion of the matrix card of the first or redundant router will not cause any defects in the output of the router. Many problems will be solved by the use of a non-glitching clock multiplexing circuit, which is used to switch between a locked state and a non-locked state, and is used to switch between clocks. This problem can be caused when the master clocks 134 and 154 have slightly different frequencies. When the router matrix card moves or becomes invalid, this result is inevitable. However, the insertion of the router matrix card does not necessarily cause this problem. In other words, the re-inserted router matrix card is best not to become the main card until it is needed.

An exemplary logical execution of Table I described above is shown in the state diagrams shown in FIGS. 4 and 5. More specifically, the first state machine 148 has three states: the first ("Master" (or "M")) state 158, where the first state machine 148 will send the signal CLK-A to the multi-rack broadcast router 100 The instructions of all clock-required components are sent to the first master clock 134; the second ("backup" (or "B")) state 160, where the first state machine 148 will not send the signal CLK-A to the multi-rack broadcast The instructions of all clock-requiring components of the router 100 are sent to the first master clock 134; and the third ("dead" (or "D")) state 162, in which the first state machine 148 will again not send the signal CLK -A The instructions sent to all clock-requiring components of the multi-chassis broadcast router 100 are sent to the first master clock 134. Initially, the first state machine is in the first state 158. In this state, the input from the routing engine 140 indicates that the first router matrix card 102A is present and operating, and the input from the sending expansion port 146 indicates that it has been locked. The input from the routing engine 150 and the input from the transmission expansion port 146 are irrelevant. In the first state 158, the first state machine 148 sends a signal to the first master clock 158 to instruct the first master clock 158 to provide the common clock signal CLK-A to all clock-requiring components of the multi-rack broadcast router 100. In addition, since all the clock-requiring components of the multi-rack broadcast router 100 are receiving the common clock signal CLK-A from the first master clock 134, the status of the broadcast router is "all", that is, all the broadcast router components 102, 104, Both 106 and 108 are running.

Regardless of the operating conditions of the second master clock 154, the first master clock 134 will continue to provide the common clock signal CLK-A, knowing that the routing engine 140 or the sending expansion port 146 is invalid. If the input from the routing engine 140 changes, the routing engine is invalid, which now means that the first router matrix card 102A does not exist or is no longer running. If the input from the transmission expansion port 146 indicates that the clock signal is no longer continuous, it will appear that the transmission expansion port is invalid. If one of these conditions occurs, the first state machine 140 will transition to the third state 162. In this state, the first state machine 148 sends a signal to the first master clock 134 so as not to distribute the common clock signal CLK-A to the clock demand components of the multi-rack broadcast router 100. As can be seen in Table I, it will be determined according to the state of the second state machine 156 whether all, some or no clock-requiring components will have a common clock signal in the broadcast router 100.

The first state machine 148 will transition from the third state 162 to the first state 158 or the second state 160. This transition will occur when the input from the routing engine 140 again indicates that the first router matrix card 102A is present and operating, and the input from the sending expansion port 146 again indicates that the port is locked. The specific transition that will occur is determined according to the situation of the second state machine 156. More specifically, if the second state machine 156 is in the first ("master") state 164, the second state machine 156 currently sends a signal to the second master clock 154 in order to distribute the common clock signal CLK-B to The clock requirement component of the broadcast router 100. If the second master clock is distributing the common clock signal CLK-B, the third and fourth inputs to the first state machine 148 indicate that the redundant router matrix card 104B is ready and the transmission expansion port 152 is locked. Correspondingly, if the first state machine 148 sends an instruction not to distribute the common clock signal CLK-A to the first master clock, the first state machine 148 will transition to the third state 160. However, if the second state machine 156 is in any other state, the first state machine 148 will transition to the first state 158. In the first state 158, the first state machine 148 will again send a signal to the first master clock 134 , In order to distribute the common clock signal CLK-A.

The first state machine 148 will transition from the second state 160 to the third state 162 or the first state 158. The transition to the third state 162 may occur independently of the second state machine 156. Specifically, if the first input indicates that the routing engine 140 is invalid, or if the second input indicates that the transmission expansion port 146 is invalid, the first state machine 148 will transition to the third state 162. On the other hand, the transition to the first state 158 occurs only when the second state machine 156 is undergoing a transition. Specifically, if the second state machine 156 transitions from the first state 164 to the third state 168, the third or fourth input to the first state machine 148 will indicate that the redundant router matrix card 104B is not ready, and/or The transmission expansion port 146 is not locked.

Next, referring to FIG. 5, the state machine has four states: the first state 164, in which the second state machine 156 will send the signal CLK-B to all clock-required components of the multi-rack broadcast router 100 to the second master. Clock 154; second state 166, in which the second state machine 156 will not send the signal CLK-B to all clock demand components of the multi-rack broadcast router 100 instructions to the second master clock 154; third state 168, where The second state machine 156 again sends the instruction not to send the signal CLK-B to all the clock-requiring components of the multi-rack broadcast router 100 to the second master clock 154; and fourth ("waiting" (or "W")) State 160, where the second state machine 156 again sends an instruction not to send the signal CLK-B to all clock-requiring components of the multi-rack broadcast router 100 to the second master clock 154. Initially, the second state machine 156 is in the second state 158. In this state, the input from the routing engine 140 indicates that the first router matrix card 102A is present and operating, and the input from the sending expansion port 146 indicates that it has been locked. Similarly, the input from the routing engine 150 indicates that the redundant router matrix card 104B is present and operating, and the input from the sending port 152 indicates that it has been locked. In the second state 166, the second state machine 156 sends a signal to the second master clock 154 in order to instruct the second master clock 154 not to provide the common clock signal CLK-B to all clock-requiring components of the multi-rack broadcast router 100 .

The second state machine 148 can transition from the second state 166 to the third state 168 or the first state 164. The transition to the third state 162 may be independent of the second state machine 156. Specifically, if the input from the routing engine 150 indicates that the redundant router matrix card 150 is invalid, or the input from the sending expansion port 156 indicates that it is no longer locked, the state machine 156 will transition to the third state 168. In the third state 168, the state machine 156 will send an instruction again to the second master clock 154, thereby instructing the master clock 154 not to distribute the common clock signal CLK-B to the clock demand components of the multi-rack broadcast router 100. Conversely, once the first state machine 148 transitions from the first state 158 or the second state 160 to the third state, the second state machine 166 can only transition from the second state 166 to the first state 164. Once the input from the routing engine 140 indicates that the first router matrix card 102A is invalid, or the input from the sending expansion port 146 indicates that the clock signal is no longer continuous, the second state machine 156 is recommended to make such a transition. If one of these conditions occurs, the second state machine 156 will transition from the second state 166 to the first state 164. In this state, the second state machine 156 sends a signal to the second master clock 154, thereby distributing the common clock signal CLK-B to the clock demand components of the multi-rack broadcast router 100.

The second state machine 156 can only transition from the first state 164 to the third state 168. This transition will occur once the first state machine 148 transitions from the first state 158 or the second state 160 to the third state 162. Once the input from the routing engine 140 indicates that the first router matrix card 102A is invalid, or the input from the sending expansion port 146 indicates that the clock signal is no longer constant, the second state machine 156 is recommended to make such a transition. If one of these conditions occurs, the second state machine 156 will transition from the first state 164 to the third state 168. In this state, the second state machine 156 sends a signal to the second master clock 154, so that the common clock signal CLK-B is not distributed to the clock demand components of the multi-rack broadcast router 100.

The second state machine 156 can only transition from the third state 168 to the fourth state 170. Once the input from the routing engine 150 indicates that the redundant router matrix card 104B is present and operating, and/or the input from the sending expansion port 152 indicates that the port is locked, only such a transition will occur. In the fourth state 170, the second state machine 156 sends a signal to the second master clock 154, so that the common clock signal CLK-B is not distributed to the clock demand components of the broadcast router 100. Finally, the second state machine 156 can transition from the fourth state 170 to any of the first, second, and third states 164, 166, and 168. More specifically, if the input from the routing engine 140 indicates that the first router matrix card is invalid, and/or the input from the sending expansion port 146 indicates that the port is not locked, the second state machine 156 will transition to the first state 164 . Conversely, if the input from the routing engine 140 indicates that the first router matrix card 102A is present and operating, and the input from the sending expansion port 146 indicates that the port is locked, the second state machine 170 will transition to the second state 166. Finally, if the input from the routing engine 150 indicates that the redundant router matrix card 104B is invalid, and/or the input from the sending expansion port 152 indicates that the port is not locked, the second state machine 170 will transition to the third state 168 .

Of course, although the preferred embodiments of the present invention have been shown and described herein, those of ordinary skill in the art can make various modifications and other changes without departing from the spirit or principle of the present invention. Therefore, the protection scope of the present invention is not limited to the embodiments described herein, but is only limited by the appended claims.