Mobile communication apparatus

(22) In day (24) Lopedag (41) Aim. avail.

2000.11.14

2000.11.14

2001.05.16 (86) Int. Entry date and search number (85) Transfer day (30) Priority

1999.11.15, JP, 323656/99 (71) Soker (72) Inventor (74) Proxy

Hitachi Ltd, 6, Kanda Surugadai 4-chome, Chiyoda-ku, Tokyo 101, JP

Satoshi Tanaka, Chiyoda-ku, Tokyo, JP

Kazuo Watanabe, Chiyoda-ku, Tokyo, JP

Masao Hotta, Chiyoda-ku, Tokyo, JP

Toyohiko Hongo, Chiyoda-ku, JP

Taizo Yamawaki, Chiyoda-ku, JP

Masumi Kasahara, Chiyoda-ku, Tokyo, JP

Kumiko Takikawa, Chiyoda-ku, Tokyo, JP

Bryn & Aarflot AS, 0104 Oslo (54) Designation Mobile communication apparatus (57) Summary A combined transmitter / receiver suitable for large-scale integration uses direct conversion reception to reduce the number of filters. The number of voltage-controlled oscillators is also reduced by using dividing circuits (105, 115, 116, 119, 120, 141) to supply a receiver and a transmitter with local oscillator signals at an RF band. The dividing circuits (105, 115, 116) each have a first division ratio which is used to generate local oscillator signals for the receiver, while a divider circuit (119, 120, 141) having a switchable divider ratio is used to generate the local oscillator signal for the transmitter. In addition, a variable gain variable gain amplifier (108) is provided for baseband signals.