Voice and data signal discriminator - has power level detector feeding integrator whose output is compared with reference level

摘要

The discriminator circuit is applicable to telephone systems where voice and data signals derived from computer and telegraphic facilities use the same lines. The numeric data should be in either frequency or phase modulated form. Input signals are initially fed into a power level detector (2) providing an approximately DC output proportional to the input power. This is integrated (3) in a circuit having a time constant of about 20 milliseconds. The output from the integrator and a threshold reference level (5) provide the inputs to a comparator (4). The two state output depends on the value of the integrated signal compared to that of the reference level. A bistable circuit (6) acts as memory for the discriminator.