| 摘要 |
PURPOSE:To simplify a channel converter circuit of a multiple carrier terminal- office device with expensive LC filters reduced in number, by making it possible to select any channel from a multiple channel easily. CONSTITUTION:A multiple signal in a basic-group band from input terminal 1 of the channel conversion part is applied to the 1st converter 4 for channel conversion and the oscillation frequency of voltage control oscillator 2 is frequency-converted, through the control of channel control circuit 3, into an assigned frequency as the 1st carrier. The output of converter 4 after frequency conversion is applied via channel filter 5 to the 2nd modulator 6, where it is modulated by the 2nd carrier of 48KHz before being outputted as a sound frequency band signal from output terminal 7. Then, a sound frequency band signal with channels CH1 to CHn demodulated is outputted by changing the carrier of oscillator 2 to frequencies (f1) to (fn). |
