The Model 157 is a precision source of selectable sine, square, or triangle waveforms that are generated from 100 μΗz (2% hours per cycle) to 1 MHz in 10 ranges. Output amplitudes are selectable from 1 millivolt to 10 volts, peak-to-peak, into a 50-ohm load. This instrument incorporates a voltage-controlled generator that may be swept over a 1000:1 frequency ratio with a 0-volt to 5-volt analog input for frequency modulation of the selected output frequency. Four modes of operation can be programmed with the front-panel controls. Three modes of operation are programmable from a remote source by static logic levels or contact closures. Frequency, amplitude, and function also are programmable from either the front-panel controls or a remote source. The instrument is packaged for mounting in a standard 19-inch rack or for operating on a test bench.