| 摘要 |
The tone generator for providing PCM signal without A/D converter comprises a tone signal generator (100), a channel selecting/ distributing cct. (200), a tone freq. generator (300), and an output cct. (400). (100) comprises a counter (10), an EPROM (15) for storing the tone signal period, and a multiplexer (20) for providing on/off signal. (200) comprises a counter (25), an EPROM (30) connected with (20), and a data selector (35), (300) comprises a shift register (40) , a counter (45), and an EPROM for storing various tone freq. (400) comprises a shift register (55) connected with (35) and (50), a D flip flop (60), and a shift register (65) for providing tone signal through a highway output tap (THW).
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