| 摘要 |
A conversion circuit for use with digital telephone switching equipment for converting pulse amplitude modulation (PAM) signals into pulse code modulated (PCM) signals and for converting PCM signals into PAM signals. When these conversions are done it is desirable to adjust the magnitude of the signals involved to take into account the differing losses in the associated analogue circuitry. The present invention employs digital pads, in the digital portion of the conversion circuit and controlled by a storage register, in order to introduce variations in the signal levels.
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