| 摘要 |
The ASK Modulation Modem (Amplitude Shift Keying) is employed in full-duplex data transmission systems in television networks such as cable, radio system etc. The modem comprises two signal paths, a transmission path made of a modulator (M) and a local oscillator (OL) which takes over the signal from the transmission channel of the computer interface and, after modulation, sends in to the network by means of a separation circuit (CS), and a second signal path namely the reception path, which takes over the signal from the network through the separation circuit (CS) and after processing through a band-pass filter (FTBR) and an intermediate-frequency amplifier (AFI) and a level converter (CN) delivers said signal as a pulse train to the reception channel of the computer interface (RXD), the whole communication protocol being provided by the computer by means of the series communication interface.
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