The 736-A wave analyzer is used to measure the amplitude of the individual harmonic components (sinusoids) that make up the spectrum of an electrical signal. It works in the frequency range between 20 Hz and 16.5 kHz and measures voltages between 30 microvolts and 300 volts. It is basically a selective tube voltmeter with a 4 Hz bandwidth; can be considered the forerunner of the modern spectrum analyzer.
