Sine wave to square wave converter circuit diagram analysis

This sine wave to square wave converter circuit promises to provide a nice square wave, changing the sine wave delivered from the existing generator. Its main feature is that it does not require a power supply: in this way it can be simply connected between the sine wave generator and the device under test.

The input sine wave maintains the voltage multiplier formed by C1, C2, D1 and D2 to power the IC. IC1A amplifies the input sine wave and the other inverters included in IC1 square the signal and provide an output square wave with equal mark/space ratio and good rise and fall times throughout the 20Hz-20KHz range.

Sine Wave to Square Wave Converter Circuit Notes:

Minimum sine wave input amplitude required for good performance: 750mV RMS.

Best performance is obtained with input sine wave amplitudes starting at 1V RMS.

The output square wave amplitude is proportional to the input amplitude.

Output square wave amplitude for 1V RMS input: 3V peak-to-peak, with R2 set to maximum.

Minimum output square wave amplitude: 2V peak-to-peak, with R2 set to maximum.

Replacing the two silicon diodes with germanium types (such as AA118, AA119) can lower the minimum input threshold.