A wave synthesizer

[摘要] A wave synthesizer has been constructed that converts a 60 cycle saw-tooth input into an output consisting of either 120 cycle, 300 cycle, or 600 cycle sine wave (the second, fifth, and tenth harmonics of 60 cycles), or any combination thereof. Each harmonic is variable in amplitude and phase. The synthesizer utilizes three harmonic channels, each consisting of a frequency-selective amplifier, which is a cascode amplifier with a twin-T feedback network, an RC phase shifting circuit, and a parallel plate adding circuit. A single saw-tooth input is common to all channels. The report contains a theoretical analysis of the transfer function of the twin-T network, an analysis of the gain characteristics of the cascode amplifier, and an over-all analysis of the frequency selective characteristics of the combined circuit. The actual operation of the circuits constructed is shown through experimental data and photographs of wave traces on the screen of the cathode ray oscillograph. Peculiarities observed in the operation are discussed. Based on the theoretical study, the experimental data obtained from the three circuits constructed, and the experience gained in constructing them, data is included in the report for the construction of a synthesizer containing channels for the first ten harmonics of 60 cycles, designed to operate on a single saw-tooth input and furnish an output consisting of any of the ten harmonics or any desired combination of them.

[发布机构] Rice University