SU605322A1 - Arrangement for measuring noise level at speech pauses - Google Patents

Description

one

The invention relates to radio engineering and can be used to determine the level of noise in electroacoustic and telephone systems.

A device is known for measuring the noise level in speech pauses, containing, its successively connected amplifier and amplitude detector, as well as the execution unit 1.

However, in the known device, to achieve a given accuracy of measuring the noise level, a significant complication of the circuit is necessary, which leads to an increase in size and weight, and also makes it difficult to configure the device.

The purpose of the invention is to improve the accuracy of a certain noise level.

To do this, a device for measuring the noise level in the pauses of speech, containing its series-connected amplifier and amplitude detector, as well as the executive unit, introduced a series-connected synchronous integrator, amplitude selector and first pulse counter, as well as a pulse generator, second pulse counter and sequentially connected ban element, adder, digital-to-analog converter and integrator, while the output of the amplitude detector is connected to the first input of the synchronous integrator, the second input

which is connected to the output of the pulse generator and to the input of the second pulse counter, the output of which is connected to another input of the first pulse counter and to the first input of the prohibition element, the second input of which is connected to the output of the first pulse counter and to another input of the adder, and the integrator output is connected to another to the input of the selector selector and to the input of the additional unit.

The drawing shows a structural electrical circuit of the proposed device.

A device for measuring the noise level during speech pauses contains a series-connected amplifier 1, an amplitude detector 2 and an executive unit 3, a series-connected synchronous integrator 4, an amplitude selector 5 and a first pulse counter 6, as well as a pulse generator 7, a second pulse counter 8 pulses and serially connected the prohibition element 9, the adder 10, the digital-to-analog converter 11 and the integrator 12, while the output of the amplitude detector 2 is connected to the first input of the synchronous integrator 4, the second input of which is connected nen pulses output from generator 7 and to the input of the second counter 8 pulses whose output is connected to another input of the first pulse counter 6 and to the first

the input element 9 of the ban, the second input of which is connected to the output of the nerve counter 6 pulses and to another input of the adder 10, and the output of the integrator 12 is connected to another input of the amplitude selector 5 and to the input of the executive unit 3.

The device works as follows.

The synchronous integrator 4, connected to the input of the amplitude selector 5, at its output creates discretized signals of the enveloped speech, which descend with a given frequency of the pulse generator 7. In this case, the sampling rate of the speech envelope in the proposed device is, for example, 50–40 Hz, and the integration time intervals T, respectively, are about 20–25 (fundamental studies of the sampling of the speech envelope indicate that the sampling rate of 50–40 Hz is optimal for it ).

At the same time, the charging time of the RC circuit of the synchronous clock controller 4 to achieve high linearity of the device is taken

t: s 10Gi „„,

and the time of discharge is indicated by an RC-chain in a synchro integrator 4

p: Gui „„ / 25.

By using a controlled synchronous integrator 4 in the device, the reliability of the noise level is improved. From the output of the amilite selector 5, signals are sent to the signal input of the nerve counter of 6 pulses. The signal input of the second pulse counter 8 is supplied with a signal from the output of the pulse generator 7. In this case, the counters 6 and 8 of the pulses can be filled during the measuring cycle determined by the time when the pulse counter 8 is filled with continuously operating pulses of the pulse generator 7. At the same time, the time of this cycle is taken so that it is more likely to follow the natural pauses in speech (i.e., more than 0.8-1.2 s). The signal from the output of the counter 6 pulses. It is fed to the first input of a reversible adder of 10 pulses with a memory, which in the initial state has a zero state. The pulses from the output of the counter 8 pulses through the prohibition element 9 are fed to the second input of the reversible adder 10 pulses with memory. If the pulses at the output of counters 6 and 8 occur simultaneously, the prohibition element 9 does not transmit pulses to the second reversing input from the mmator 10 pulses with memory. Each pulse transmitted to the first input of the reversible adder 10 pulses with memory from the pulse counter 8 increases the cut-off voltage from the output of the digital-to-analog converter 11, which is connected to the control input of the amplitude selector 5 through the integrator 12. Pulses counter output 6 pulses

accordingly, this voltage is reduced (this voltage can vary within the limits that lie between the zero and upper stages of the digital-to-analog converter And). The pulse counter 6 stops producing pulses when the samples that characterize the speech envelope at its input begin to fail with gaps. In this case, by resetting the counter of 6 pulses by the counter 8, the counter of 6 pulses will not allocate countable pulses at all. Therefore, if there are no noise in the pauses, the voltage at the control input of the amplitude selector 5 will be zero (or applied to zero if the speech signal is not accompanied by noise). In the presence of noise, this voltage at the output of integrator 12 will, after a while, be set to a level close to the likely noise level in speech pauses. This voltage is applied to the execution unit 3. As the execution unit 3, for example, there may be a visual or audible alarm indicating an unacceptable noise level or a constant component of the noise in the speech envelope.

Variants of the device circuit may be different in that a set of band-pass filters for spectral analysis, or an isophotometric filter, or a measuring microphone can be inserted into their input part.

The given accuracy of determining the level of the Schuma by the proposed device is achieved by selecting the required number of bits of the D / A converter.

The use of the device for the purpose of compensating for the noise component in the speech envelope emitted in speech-transforming devices ensures the improvement of the qualities and intelligibility of the speech signal being restored in them.

The proposed device will significantly improve the accuracy of determination in comparison with the known devices — the noise level in the same measuring dynamic range due to the use of a synchronous integrator in the circuit and the digital circuit of the device; significantly reduce the size and weight, as well as improve the reliability of the device.

Claims (1)

Invention Formula A device for measuring the noise level during speech pauses, containing a serially connected amplifier and an amplitude detector, as well as an extra block, characterized in that, in order to improve the accuracy of determining the noise level, sequentially connected synchronous integrator, amplitude selector and the first counter of impulses are entered into it, as well as a pulse generator, a second pulse counter and a successively connected prohibition element, an adder, a digital-to-analog converter and an integrator, the output of the amplitude detec torus is connected to the first input of the synchronous integrator, the second input of which is connected to the output of the pulse generator and to the input of the second pulse counter, the output of which is connected to another input of the first pulse counter and to the first input of the prohibition element, the second input of which is connected to the output of the first pulse counter another input of the adder, and the output of the integrator is connected to another input of the amplitude selector and to the input of the execution unit. Sources of information taken into account in the examination 1. Authorship of the USSR No. 466621, cl. H 04B 3/04, 1973.