The 6500A Digital Phasemeter is an ideal source instrument for precision, phase angle measurements. It is suited for a broad range of applications, including monitoring of servo control systems, low impedance measurements, adjustment of crystal resonance, testing and adjustment of filter networks, controlling laser trimming of resistor networks, measurements in AC power systems, calibration laboratories and general testing and measurement. Operation of the 6500A requires only selecting the proper input level for each channel and observing the readout in degrees. The 6500A offers precision angle measurements with 0.05? accuracy and 0.01? resolution. It provides phase measurements over a broad frequency range of 3Hz to 5MHz and accepts a variety of input waveforms including sine, triangle, square waves and positive pulses. Input signal level for the 6500A is from 10 mV to 120 V rms. Direct readout of phase angles between 0? and 360? is obtained via a digital, planar gas discharge display.