| 摘要 |
<p>A TDMA cellular telephone (600) includes, in its transmit signal path, microphone (608), vocoder (612), data format circuitry (601), quadrature modulator (602), 90 MHz local oscillator (606), transmitter with mixer (604), transmitter filter (618), and antenna (620). In its receive signal path, the TDMA cellular telephone (600) includes receiver filter (622) coupled to antenna (620), quadrature demodulator (624), and data deformat circuitry (625). The channel frequency of TDMA cellular telephone (600) is loaded into synthesizer (616) by microcomputer (614) and applied to transmitter (604) and demodulator (624). TDMA cellular telephone (600) is controlled by microcomputer (614) which includes a memory with a control and signaling computer program stored therein. Transmitter (604) includes novel power control circuitry (100) comprised of variable gain stage (104), mixer (106), bandpass filter (109), and directional coupler (112) in a forward path, and detector (116), A/D converter (118), digital controller (120), and D/A converter (126) in a feedback path.</p> |
