摘要 |
In a control circuit for the two speech paths of a hands-free telephone, logarithmic analog to digital converters 133,134 generate digital words corresponding to the signal amplitudes on the two paths. These words are compared with stored references in decision logic and the relative attenuation of the paths is adjusted by switched attenuators 131,132 according to the result of this comparison. The total loop gain is maintained substantially constant. <IMAGE> |