Panasonic VP-7721A Manual

1. GENERAL1.1 OutlineThe Model VP-7721A Audio Analyzeris a versatile audio measurementsystem that combines a low-dis¬tortion signal source with threefunctions in one unit as illustrat¬ed in Fig. 1-1.Since the distortion measurementfrequency is tuned to the oscil¬lator frequency, the instrumentis most effectively used as anautomatic tuning distortion Fig. 1-1 Functional construction othe VP-7721ameasurement set.Besides the normal mode of operation using digital displays and autoranging meters, the VP-7721A can perform preset operations. TheVP-7721A stores sixteen front panel setups and recalls them at a timewhenever needed.The operational ease has been largely improved by microprocessorcontrol, however, the analyzer is compact in size measuring only 10 cmhigh and 35 cm deep. It is convenient for use in the production orinspection line and on service benches as well as research and develop¬ment of audio equipment.1.2 OscillatorSignal source used in the VP-7721A is a "bridged-T" oscillator whichprovides a sine—wave signal from 5 Hz to 159.9 kHz. It attains a dis¬tortion factor of 0.002% or less in the range of 50 Hz to 20 kHz. Themaximum output voltage is 1.58 V rms into a 600-ohm load (3.16 V rmsopen-circuited) and can be attenuated in 0.1-dB steps by an attenuatorwith a total attenuation of 79.9 dB. Either display in dBm (0 dBm =1 mW into 600—ohm) or dB (0 dB = 1 V rms, into 600—ohm) is selectable.The direct reading range covers -73.7 dBm to 6.2 dBm or -75.9 dB to 4.0dB (0.16 mV to 1.58 V rms) .The four 7-segment LED’s indicate frequencies up to four digits andoutput amplitudes up to three drgits (with a minus sign) - The lowerOutput Input