| 摘要 |
<p>A digital pad switch DSP is inserted in a highway JHW<Sub>1</Sub>, JHW<Sub>2</Sub> of the time-division speech network. For an input signal, from incoming highway JHW<Sub>1</Sub>, the digital pad switch DSP is operable to send out, on outgoing highway JHW<Sub>2</Sub>, any selected one of the following: a signal the same as the input signal, signals corresponding to the input signal as attenuated by predetermined amounts, and a zero level signal.</p><p>The digital pad switch has read only memories ROM<Sub>o</Sub>, ROM<Sub>3</Sub>, ROM<Sub>5</Sub>, ROM<Sub>6</Sub> and ROM<Sub>∞</Sub>. Each ROM has an address corresponding to each possible input signal. In response to the input signal ROM<Sub>o</Sub> sends out an identical signal, ROM<Sub>3</Sub>, ROM<Sub>5</Sub> and ROM<Sub>6</Sub> send out respective signals corresponding to the input signal as attenuated by 3 dB. 5 dB and 6 dB respectively. ROM<Sub>∞</Sub> sends out a zero level signal.</p><p>Under control of pad switch control memory PSM the selector SEL sends out only the signal from the appropriate ROM to highway JHW2.</p> |
