Acoustical testing system

Claim 2

An acoustical testing system comprising: osciLlator means for generating a selected signal frequency; amplifier means for receiving said signal frequency and amplifying same to provide an amplified driving signal; means coupling said driving signal to an acoustical device to be tested; means receiving an output from the device to be tested and automatically processing such output to operate readout means to provide a readout of the sound pressure level of the device; and distortion analyzer means receiving an output signal from said receiving and processing means and automatically processing said output signal to operate further readout means to produce a readout of the harmonic distortion of the signal from the device under test.

Claim 3

An acoustical testing system according to claim 1 wherein said coupling means includes sound pressure chamber means in which the device to be tested is disposed.

Claim 4

An acoustical testing system according to claim 1 wherein said output receiving means comprises calibrated amplifier means and detector means, feedback means connected between said detector means and said calibrated amplifier means for automatically controlling operation of said calibrated amplifier means.

Claim 5

An acoustical testing system according to claim 3 wherein said calibrated amplifier means comprises resistance means of increasing values connected together at output ends thereof, cascaded 20 dB amplifier means, switch means connected in series with input ends of each of said resistance means and connecting the outputs of said amplifier means to said resistance means, and said feedback means connected to said switch means to operate same.

Claim 6

An acoustical testing system according to claim 3 wherein said detector means comprise comparator means for providing output signals upon receipt of predetermined voltage level of an input signal, counter means receiving said output signals and producing up or down count output signals, decoder means connected to said counter means and operated by said up or down count output signals to provide control output signals defining said feedback means.

Claim 7

An acoustical testing system according to claim 5 wherein further comparator means receive said input signal to provide output gate-operating signals, gate means receiving said gate-operating signals to operate same to produce a counter-operating signal, further counter means receiving said counter-operating signal to provide a decoder-operating signal, decoder means receiving said decoder-operating signal and producing a generator-operating signal, and generator means receiving said generator-operating signal and producing a comparator-operating signal that is supplied to said further comparator means.

Claim 8

An acoustical testing system according to claim 1 wherein said distortion analyzer means comprises pulse generator means for producing pulses, cascade-connected divider circuit means receiving said pulses and operated thereby to produce switch-operating signals, switch means having known, unknown and switch-operating signals supplied thereto with said switch-operating signals operating said switch means to produce integrator-operating signals, integrator means receiving said integrator-operating signals and supplying comparator-operating signals, comparator means receiving said comparator-operating signals and producing display-operating signals when said comparator-operating signals reach a predetermined voltage level, and display means responsive to said display - operating signals for indicating the amount of distortion.

Claim 9

An acoustical testing system according to claim 1 wherein said oscillator means comprises means for setting the frequency at which said oscillator means will operate, feedback means provided by said oscillator means including variable gain means, control means connected to said variable gain means to maintain the total feedback gain at unity thereby sustaining said oscillator means at a desired amplitude.

Claim 10

An acoustical testing system according to claim 1 wherein said Distortion analyzer means includes an automatic voltage control circuit including a light-sensitive resistance means, signal amplifier means connected to said resistance means, and feedback circuit means including detector means connected to the output of said signal amplifier means and to a light-generating means including storage means and comparator means, said comparator means comparing the amplified and detected signal stored in said storage means with a reference voltage to provide an operating signal to operate said light-generating means and the light being generated by said light-generating means is a function of said operating signal which light impinges on said resistance means thereby varying the resistance thereof.

Claim 11

An acoustical testing system according to claim 1 wherein said readout of the sound pressure level and said readout of the harmonic distortion occurs substantially simultaneously.

Claim 12

An acoustical testing system comprising: signal generating means for generating a selected signal; means for receiving said selected signal including means for providing a driving signal; means coupling said driving signal to a device to be tested; means receiving an output from the device to be tested and automatically processing such output to operate readout means to provide a readout of the sound pressure level of the device; and means receiving an output signal from said receiving and processing means and automatically processing said output signal to operate further readout means to produce a readout of the harmonic distortion of the signal from the device under test, said readout of the sound pressure level and said readout of the harmonic distortion occurring substantially simultaneously.

Claim 13

An acoustical testing system comprising: signal generating means for generating a selected signal; means for receiving said selected signal including means for providing a driving signal; means coupling said driving signal to a device to be tested; means receiving an output from the device to be tested and automatically processing such output to operate readout means to provide a readout of the sound pressure level of the device; and means receiving an output signal from said receiving and processing means and automatically processing said output signal to operate further readout means to produce a readout of the harmonic distortion of the signal from the device under test, said readout of the sound pressure level and said readout of the harmonic distortion occurring substantially simultaneously.