| 摘要 |
A compander system comprises an improved gain control module 10 and an improved detector 12 which are adapted to be manufactured in integrated circuit form. The gain control module 10 includes an op-amp with two feedback paths for respective (polarity) representations of the input signal and each includes a log circuit, provision for adding a gain control signal, and an antilog circuit, a bias current independent of temperature being caused to pass through the log and antilog circuits. The detector 12 includes a rectifying op-amp having respective current conductor paths for different representations of its input signal connecting the input and output of the op-amp, a signal generator producing a signal responsive to the passage of current through one such path and of a form which is an inverted version of the input signal, a log circuit and a low pass filter connecting the output of the rectifying op-amp with the gain control module, and a second bias being applied to the current conduction paths and to the signal generator to reduce the slow rate of the rectifying op-amp. <IMAGE> |
