Measuring amplitude and phase response of measurement instrument with binary phase shift keying test signal

A system, comprising:

• an exclusive-OR gate having:
• a first input configured to receive an RF carrier signal having an RF carrier frequency, a second input configured to receive a square wave signal having a square wave frequency, and an output configured to output a binary phase shift keying (BPSK) signal comprising the RF carrier signal modulated by the square wave signal;
• a measurement channel having an input and an output, wherein the input is connected to receive the BPSK signal, and wherein the measurement channel is configured to provide at the output in-phase (I) and quadrature-phase (Q) time records of the BPSK signal;
• an acquisition memory configured to receive and to store therein the I and Q time records;
• and
• a digital signal processor configured to:
• take derivatives of the I and Q time records;
• find a highest impulse response in the I and Q time records, and circularly rotate the I and Q time records so that the highest impulse response occurs at time zero;
• take a Fast Fourier Transform of the circularly rotated I and Q time records, retaining only FFT data at frequencies and harmonics of the square wave frequency;
• correct amplitudes of the FFT data for a frequency characteristic of the square wave signal to obtain an amplitude response of the measurement channel of the measurement instrument;
• unwrap a phase response of the amplitude-corrected FFT data across a measured frequency span;
• take a derivative of the unwrapped phase response of the amplitude-corrected FFT data and removing any residual group delay offset to obtain a group delay response of the measurement channel of the measurement instrument;
• and
• integrate the group delay response to obtain a phase response of the measurement channel.

A system, comprising:

• an exclusive-OR gate having:
• a first input configured to receive an RF carrier signal having an RF carrier, a second input configured to receive a square wave signal having a square wave frequency, and an output configured to output to a signal processing channel under test a binary phase shift keying (BPSK) signal comprising the RF carrier signal modulated by the square wave signal;
• and
• a digital signal processor configured to receive from the signal processing channel in-phase (I) and quadrature-phase (Q) data produced by the signal processing channel in response to the BPSK signal, and to process the I and Q data to determine an amplitude response and phase response of the signal processing channel as a function of frequency.