Nova Patents
EP0805561A2

A method for implementing a direct conversion receiver with a six-port junction

Abstract

The invention relates to a method for receiving and demodulating information transmitted as modulated by a direct conversion receiver, which comprises a six-port junction (4). In this method the demodulation is carried out analogically.

EP0805561A2, drawing sheet 1
Sheet 1 of 32

Term

Term ended

Projected expiry passed 29 April 2017, 9.4 years ago.

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10 claims: 5 independent, 5 dependent

  1. 1
    A method for receiving and demodulating modulated information by a direct conversion receiver, which comprises a six-port junction (4), characterized in that the demodulation is carried out analogically.
  2. 2
    A method according to Claim 1, in which the received, radio-frequency signal RF is led to the first input port (5) of the six-port junction (4), and the local oscillator frequency (LO) is led to the second input port (6), whereby there are produced in the six-port junction - the first output signal (S1 ) by summing the received radio-frequency signal (RF) and the local oscillator frequency (LO), - the second output signal (S2) by subtracting the local oscillator frequency (LO) from the received radio-frequency signal (RF), - the first output signal (S3) by summing the received radio-frequency signal (RF) and the local oscillator frequency (LO) so that there is a 90° phase difference between the signals (RF, LO), and - the fourth output signal (S4) by subtracting the local oscillator frequency (LO) from the radio-frequency signal (RF) so that there is a 90° phase difference between the signals (RF, LO), whereby the power signals (P1, P2, P3, P4) of the output signals (S1, S2, S3, S4) are produced in the method, characterized in that the demodulation of the I-component of the transmitted information is carried out by subtracting the second power signal (P2) from the first power signal (P1), and the demodulation of the Q-component of the transmitted information is carried out by subtracting the third power signal (P3) from the fourth power signal (P4).
  3. 3
    A method according to Claim 1, in which the received, radio-frequency signal (RF) is led to the first input port (5) of the six-port junction (4), and the local oscillator frequency (LO) is led to the second input port (6), whereby there are produced in the six-port junction - the first output signal (S1 ) by summing the received radio-frequency signal (RF) and the local oscillator frequency (LO), - the second output signal (S2) by subtracting the local oscillator frequency (LO) from the received radio-frequency signal (RF), - the third output signal (S3) by summing the received radio-frequency signal (RF) and the local oscillator frequency (LO) so that there is essentially a 90° phase difference between the signals (RF, LO), and - the fourth output signal (S4) by subtracting the local oscillator frequency (LO) from the received radio-frequency signal (RF) so that there is essentially a 90° phase difference between the signals (RF, LO), whereby the power signals (P1, P2, P3, P4) of the output signals (S1, S2, S3, S4) are produced in the method, characterized in that the demodulation of the signal (V 21 ) corresponding to the amplitude of the transmitted information is carried out by subtracting the second power signal (P2) from the first power signal (P1), and the demodulation of the signal (V 43 ) corresponding to the phase of the transmitted information is carried out by subtracting the third power signal (P3) from the fourth power signal (P4).
  4. 4
    A method according to any one of the preceding Claims 1 to 3, characterized in that the intensity of the demodulated signal is controlled at least partly by controlling the level of the local oscillator frequency (LO).
  5. 5
    A method according to Claim 4, characterized in that the level control signal (GC1 ) of the local oscillator frequency is produced from the demodulated I-signal or the demodulated amplitude signal (V 21 ) preferably by low-pass filtering.
  6. 6
    An incoherent direct conversion receiver (1) for receiving the information transmitted as modulated, which receiver comprises a six-port junction (4), to the first input port (5) of which the received radio-frequency signal (RF) is led, and to the second input port (6) of which the local oscillator frequency is led, whereby the six-port junction comprises - means (4, 8) for producing the first output signal (S1) by summing the received radio-frequency signal (RF) and the local oscillator frequency (LO), - means (4, 9) for producing the second output signal (S2) by subtracting the local oscillator frequency (LO) from the received radio-frequency signal (RF), - means (4, 10) for producing the third output signal (S3) by summing the received radio-frequency signal (RF) and the local oscillator frequency so that there is a 90° phase difference between the signals (RF, LO) and - means (4, 11) for producing the fourth output signal (S4) by subtracting the local oscillator frequency from the received radio-frequency signal (RF) so that there is a 90° phase difference between the signals (RF, LO), and - means (12, 13, 14, 15) for producing the power signals (P1, P2, P3, P4) of the output signals (S1, S2, S3, S4), characterized in that the receiver (1) also comprises - means (16, 18, 19) for producing a signal (V 21 ) corresponding to the I-signal of the transmitted information, and - means (17, 20, 21) for producing a signal (V 43 ) corresponding to the Q-signal of the transmitted information.
  7. 7
    A coherent direct conversion receiver (1) for receiving information sent as modulated, which receiver comprises a six-port junction (4), to the first input port (5) of which the received radio-frequency signal (RF) is led and to the second input port (6) of which the local oscillator frequency (LO) is led, whereby the six-port junction comprises - means (4, 8) for producing the first output signal (S1) by summing the received radio-frequency signal (RF) and the local oscillator frequency (LO), - means (4, 9) for producing the second output signal (S2) by subtracting the local oscillator frequency (LO) from the received radio-frequency signal (RF), - means (4, 10) for producing the third output signal (S3) by summing the received radio frequency signal (RF) and the local oscillator frequency (LO) so that there is a phase difference of 90° between the signals (RF, LO), and - means (4, 11) for producing the fourth output signal (S4) by subtracting the local oscillator frequency (LO) from the received radio frequency signal (RF) so that there is a 90° phase difference between the signals (RF, LO), and - means (12, 13, 14, 15) for producing the power signals (P1, P2, P3, P4) of the output signals (S1, S2, S3, S4), characterized in that the receiver (1) also comprises - means (16, 18, 19) for producing a signal (V 21 ) corresponding to the amplitude of the transmitted information, and - means (17, 20, 21, 22) for producing a signal (V 43 ) corresponding to the phase of the transmitted information.
  8. 8
    A receiver according to Claim 6, characterized in that - the means (16, 18, 19) for producing a signal corresponding to the I-component of the transmitted information comprise a first adder (16), and - the means (17, 20, 21) for producing a signal corresponding to the Q-component of the transmitted information comprise another adder (17).
  9. 9
    A receiver (1) according to Claim 7, characterized in that - the means (16, 18, 19) for producing a signal (V 21 ) corresponding to the amplitude of the transmitted information comprise a first adder (16), and - the means (17, 20, 21, 22) for producing a signal (V 43 ) corresponding to the phase of the transmitted information comprise another adder (17).
  10. 10
    A receiver (1) according to any one of the preceding Claims 6 to 9, characterized in that the receiver (1) also comprises means for controlling the intensity of the local oscillator frequency (LO).
Independent claims10