Noise suppressor for voice plus data communications - uses noise detector and suitable delay circuit to open series switch

摘要

The noise suppressor, for communications equipment (esp. voice links with intersticed data blocks) has the received LF signal passing one way over a noise detector (2) to a delay line (3) and the other way over a second delay line (4) to a switch (5). The switch is controlled by the output of the first delay line and switches the output of the second delay line through to the amplifier (6) driving the loudspeaker (7). The delay times are chosen so that the noise detected in the LF signal can be blocked by opening the switch, ie. by the time the noisy signal reches the switch the latter is open.