| 摘要 |
<p>A communication unit (10), capable of operating in either cellular or trunked communication modes, comprises a receiver (14), a transmitter (16), and a dual synthesizer (18), coupled to the receiver and to the transmitter. The dual synthesizer comprises a main synthesizer (124) and an offset synthesizer (132). The offset synthesizer comprises a phase modulator (131) and an offset voltage-controlled oscillator (134). A protocol controller (20) comprises modulator circuitry for modulating only the offset voltage-controlled oscillator when communication unit operates in the cellular mode, and for modulating both the phase modulator and the offset voltage-controlled oscillator when the communication unit operates in the trunked mode.</p> |
