The process of PSK generation in a lab is as follows:
- Generate a sinusoidal carrier wave from a signal generator. Call it Signal A
- Use an operational amplifier to shift the phase of Signal A by a fixed amount : usually 90 degrees in case of Binay Phase Shift Keying. Call this Signal B.
- Apply Signal A and Signal B to the two inputs of a 2:1 analog multiplexer.
- Apply the data signal to the select line of the analog switch. The output of the analog switch will be the required PSK signal. The data signal is a simple digital signal with two states 1 and 0 i.e. 0 and +5V. This can be emulated using a 555 Timer wired to generate a simple square wave. The analog switch will select Signal A or Signal B depending on the logic level of this data signal thereby outputting a sine wave which abruptly changes phase as the bit value changes.