| 摘要 |
<p>A/D and D/A converters are effectively utilized in a mobile phone, for example, by multiplexing the signals before the conversion. Both time division multiplexing and frequency division multiplexing can be used. When frequency division multiplexing is used, the IF signal (D) coming from the radio part and the baseband signal (A) coming from the microphone are summed (30) before the A/D conversion (31). The converted signal (K, L) is directed through filters (32, 34) in separate branches to digital signal processing (28). After that, the coded microphone signal (I, Q) is modulated (41, 42) to the intermediate frequency and added to the received, decoded baseband signal (M). The summed signal is directed to a D/A converter (45) and thereafter the signals are again separated by means of filters (46, 47). When time division multiplexing is used, the arrangement can also be used for measuring other signals of the mobile station. <IMAGE></p> |
