Patent ID: 7728576

Claim:
An inexpensive, programmable, frequency independent, amplitude and phase shifting circuit comprising: an enclosure comprising: means for holding printed circuit boards; and a front panel for receiving input and output signals; a motherboard comprising: means for supplying input signals through said front panel; a power source; digital control lines; and a demultiplexer circuit board; said demultiplexer circuit board within said motherboard comprising: a demultiplexer; a plurality of signal receiving digital control lines coupled to the demultiplexer from a digital output card in a personal computer; a plurality of signal sending digital control lines coupled to the demultiplexer routed to an amplitude/phase shifting circuit board; and means for selecting a single amplifier for operator selected amplitude or phase gain change over a single frequency or sweep in frequency; an amplitude/phase shifting circuit board comprising: a plurality of programmable gain operational amplifiers each including a plurality of data input lines and a select line, independent of the data input lines, one amplifier selected at a time through the select line, to have its gain/and or phase changed when an operator desires a new amplitude and/or phase, each of the programmable gain operational amplifiers further including a first input signal line to receive a sine signal waveform and a second input signal line to receive a cosine signal waveform each of the sine and cosin signal waveforms are of the same frequency; a plurality of summing operational amplifiers, coupled to the plurality of programmable operational amplifers, to sum the sine signal waveform and cosine signal waveform; a plurality of output signal lines, coupled to the plurality of summing gain operational amplifiers, each output signal line to transmit a phase and/or amplitude shifted sinusoidal signal waveform having the same frequent as the summed sine signal waveform and cosine signal waveform; and means for controlling said amplitude/phase shifting circuit.