The document discusses a spectrum analyzer and function generator. A spectrum analyzer is used to display and measure frequency by mixing the input signal with a voltage controlled oscillator, filtering at an intermediate frequency, and using a detector and vertical amplifier to display the pulse output only at the input signal frequency. A function generator generates different signal types like sine, square, and triangular waves, with adjustable frequency from Hz to MHz. It uses positive feedback oscillators like RC, LC, Wien bridge, and phase shift oscillators. The block diagram of each is also included.