SU375762A1 - - Google Patents

Description

one

The invention relates to the field of measuring electrical signals and can be used in speech compression systems, in automatic speech recognition systems, as well as in phonetic studies of speech intonation.

A well-known intoner contains at the input a compressor with a tone-noise detector connected to it, as well as parallel-connected rows of series-connected band-pass filters and phasing units consisting of parallel-connected amplitude meters and a pulse former connected via a controlled delay line to the multiplier with a different input connected to an amplitude meter. The output of the multiplier is the output of the phasing unit, which, together with the outputs of the other phasing units, is connected to a pulse channel combiner. At the output of the intonometer, a period meter is connected to the inverse transform unit.

In order for this intonometer to work properly, it is necessary that the frequency of the clock generator be slightly lower than the frequency of the lower boundary of the range of measured tones, that is, the duration of the processing frame is slightly longer than the period of the lowest measured tone. This causes a significant averaging of the high tones measurements.

The purpose of the invention is to improve the measurement accuracy.

The goal is achieved by including a minimum limiter between the bandpass filters and the compressor. The input of one of the phasing blocks is connected to the output of the compressor through a peak selector. The outputs of the amplitude meters are connected via an additional series-connected adder, a pulse search unit, and a controlled generator connected to the input of a period meter, the output of which is additionally connected to the generator's control input via a prior information sensor. The output of the adder of the pulse formers is connected to the control inputs of the delay lines through the detector of the end of the frame, as well as to the second input

Amprior information sensor, with the second input of the period meter and the tone-to-noise detector’s second input, the output of the additional adder is connected to the third input; the output of the additional adder is connected to the fourth input

pulse search unit. The output of the detector "tone-noise is connected to the fourth input of the sensor prior information. The output of the controlled oscillator is connected to the input of the frame end detector and to the third input of the sensor of a priori information. The frame termination detector contains an AND connected circuit and a multivibrator in series. The a priori information sensor contains an AND circuit, an electronic key, a low-pass filter, and an adder, to which another input is connected a reference voltage generator.

FIG. 1 is a block diagram of an intonometer; in fig. 2 is a block diagram of a frame termination detector; in fig. 3 is a block diagram of a sensor of a priori information; in fig. 4 - graphs that show the work of the intonometer.

The intonometer contains a compressor /, which through a minimum 2 limiter is connected to a series of band-pass filters 3 and a direct detector "tone-noise 4 and a cyclic selector 5. The outputs of the band-pass filters 3 and the peak selector 5 are connected to the inputs of the corresponding phasing blocks b, i.e. to the inputs of the pulse driver 7 and the amplitude meter 8, which are connected together and are the input of the phasing unit 6. The pulse driver 7 through the controllable delay line 9, and the amplitude meter 8 are directly connected to the multiplier m 10, the output of which is the pulse output of the phasing block 6 and pulse outputs with phasing 6 units of other channels are connected to the pulse combiner channels, for example adder 11 connected to the pitch pulse search unit 2. In addition, pulse drivers 7 of all channels are connected to the frame 13 end detector, and amplitude meters 8 are connected to an additional adder 14 connected to the detector "tone-noise 4 and the search block for the pulses of the main tone 12, which is connected to the detector" tone 4 and controlled oscillator 15. Controlled oscillator / 5 is connected to a sensor of a priori information 16, Period meter 17 and a frame termination detector 13, the output of which is connected to controlled delay lines 9 of phasing blocks 6, detector Tonchum 4, sensor apr Ion information 16 and the period meter 17. Period meter 17 is connected to the inverse transform unit 18 and the a priori information sensor 16, to which the detector Tone Noise 4 is connected to another input.

The end detector 13 comprises an AND 19 serially connected circuit, to the input of which the outputs of pulse drivers 7 of all channels are connected, a trigger 20, a controlled oscillator 15, and a multivibrator 21 are connected to another input. The output of the multivibrator is the output of a frame end detector.

The a priori information sensor 16 comprises an AND 22 circuit in series, an electronic key 23, with the other input of which is connected to the output of the period meter 17, a low-pass filter 24 and an adder 25, to the other input of which the reference voltage generator 26 is connected.

Inputs 27, 28 and 29 of the circuit "And 22 are connected respectively to the detector" tone-noise 4, the detector of the end of frame 13 and controlled by the generator 15.

Works intonometer as follows. The speech signal from the compressor / enters the minimum limiter 2, the peak selector 5 and the detector tone-noise 4. Using the limiter minimum 2 of this speech

the signal is cut out in the middle part near the zero line (zero transitions), thus achieving the equalization of the spectrum of the input signal, i.e. the harmonics included in its composition, acquire approximately equal weight. By the band-pass filters 3 the signal with the equalized spectrum is divided into harmonics, and the peak selector 5 from the signal coming from the compressor, its maximum values are distinguished. The signals received at the outputs of the bandpass filters 3 and the peak allocator 5 / are fed to the phasing blocks 6, converted by the pulse shaper 7 to the corresponding pulse sequences, which are then phased out using controlled delay lines 9. The pulse sequences from the controlled delay lines 9 through multipliers 10 are modulated in amplitude by voltages from the outputs of amplitude meters 8, which

take into account the amplitude ratios between the signals from the bandpass filters 3 and the peak separator 5. Phased and amplitude modulated pulse sequences from multipliers 10 are combined at the adder // of the pulse channels and fed to one of the inputs of the pitch pulses 12. At the same time, the voltages from the meters amplitudes 8, which participated in the modulation of the respective channel pulse sequences, are summed in additional adder 14 and fed to another input of the search block; and 12 basic pulses toia. Since the channel pulse sequences are phased, at the output of the adder / / at the moments corresponding to the period of the fundamental tone of speech, the pulses from all channels are added. As a result, pulses of maximum amplitude are formed (equal to the sum of the amplitudes of the pulses of the individual channels), which are compared by block 12 with a voltage equal to the sum of the amplitudes from all the channels. At the moment of equality of the signals, pulses are generated at both inputs of the pulse search unit 12. Thus, at the output of block / 2, pulses are formed corresponding to the period of the fundamental tone. In real situations, due to the nonstationarity of the speech process, at the moments corresponding to the pitch period, there are no additions of impulses from all channels. The resulting pulse has an amplitude less than the sum of the voltages on the adder 14. Therefore, the signal level from the adder 14

decreases, as a result of which the difference in signal levels at both inputs of the pulse search unit 12 is eliminated and reliable selection of pulses corresponding to the pitch period is ensured. Changes in the signal level of the adder //, caused by emotional transitions in speech, do not cause a search for impulses corresponding to the period of the fundamental tone produced by block 12, since these changes occur synchronously with changes in the signal level on the adder 14.

The pulses obtained at the output of block 12, corresponding to the pitch period, are controlled by a controlled oscillator 15, which is synchronized by these pulses, to the period meter 17, which converts the temporal distances between the pulses to the corresponding voltage. With the aid of the inverse transform unit 18, this voltage is converted to a voltage proportional to the frequency of the fundamental tone. Phasing signals from pulse formers 7 corresponding to, for example, positive zero transitions of the first (plot 30 and second (plot 31) harmonics of the fundamental tone of speech occurs as follows. These signals are generated at the first outputs of the pulse formers, and on the second, pulses (plot 32 and 55) the resolution of the arrival of clock pulses (frame end pulses), which are applied to the frame 13 end detector, i.e., the ' 19. The circuit output pulses (plot 34 at those times when the resolution is at one clock pulse is present at the outputs of all pulse formers 7. The positive edge of the first pulse from circuit 19 (plot 55) triggers trigger 20, which in turn triggers multivibrator 21. Pulse (plot 36 from multivibrator 21 is used as a clock signaling the beginning of the processing frame. Regarding it, the phasing of pulse sequences (diagrams 30 and 5 /) from pulse shapers occurs 7. Other pulses from circuit 19 trigger 20 are insensitive until the pulse arrives (plot 37, a) corresponding to ne The pitch period, from the controlled oscillator 15. At this point, the trigger 20 returns to the initial state, indicating that the processing frame can be terminated. Pulse following in time for the pulse corresponding to the pitch period (plot 57a), pulse (plot 34 from circuit 19 with its positive front (plot 35 again triggers trigger 20, which in turn triggers multivibrator 21. Pulse (plot 55) from multivibrator 21 indicates the end of the current frame of processing and the beginning of a new frame, over which the described process repeats. Thus, the frame of processing the speech signal is directly dependent on the length of the measured pitch period.

The search for pulses corresponding to the period of the main tone, through the block search pulse 12 is as follows. Block 12 gives a pulse of the pitch period if its voltage at the corresponding inputs is the amplitude of the pulse from the adder // no less than the voltage from the adder 14. With such a search, faults of the second kind are possible. If the transfer coefficient of the adder 14 is small, then the level and the corresponding input of block 12 are significantly lower than the maximum amplitude pulses corresponding to the pitch period at the other input, and the block gives a false decision,

extra pulses. If the transfer coefficient of the adder 14 is close to one, block 12 transmits the necessary pulses corresponding to the period of the fundamental tone. In order to increase the reliability of the search for pulses corresponding to the pitch period, a sensor of a priori information 16 is introduced, the main task of which is to generate a forced frame termination signal in the event that

pulse period of the fundamental tone, and the period meter 17 must reproduce the value corresponding to the period of the fundamental tone in the previous frame processing. Such a system is less sensitive to pulse skips of the pitch period, which allows the comparison threshold for the pulse search unit 12 to be increased by increasing the ha of the transfer coefficient of the adder 14 and, as a result, reducing errors such as false alarms, which ultimately increases the reliability of measurements.

This is done in the following ways. If there are no pulses of the pitch period at the output of block 12, then the controlled oscillator 15 puts the intonometer into standby mode, i.e., prepares it for processing the speech signal with any pitch period in the range of measured tones. At this moment, from the reference voltage generator

26 through the adder 25, the reference voltage is applied and it operates in a self-oscillating mode with a frequency of free oscillations below the lower boundary of the measured tones. The pulses from the output of the pulse search unit 12 are synchronized by the controlled oscillator 15 and through it are transmitted to the AND 22 circuit, which opens the key 23, through which the voltage corresponding to the pitch frequency enters the filter 24.

This voltage through the adder 25 controls the oscillation frequency of the controlled oscillator 15 and sets it approximately one and a half times smaller than the average pitch frequency value obtained at the output

filter 24. Thus, if the pulse finder 12 passes the pulse of the pitch period, then the key 23 is opened, and the average voltage from the filter 24 controls the generator 15 so that it produces a pulse,

referred from clock to time interval.

corresponding to the half value of the average pitch period.

Since the addition of pulses from all channels on adder 11 is possible in principle at times equal to or multiples of the pitch period, when a pulse is passed that corresponds to the pitch period, the next pulse with the largest amplitude is the pulse corresponding to twice the period. If block 12, due to the nonstationarity of the speech process, passes a pulse of the pitch period and extracts a pulse corresponding to twice the period, then a gross error occurs in the measurement of the frequency of the fundamental tone.

In this case, if block 12 transmits a pulse corresponding to the pitch period, then a gross error does not occur, because after a time interval of one and a half times the pitch control period averaged over previous values of the pitch period, the controlled oscillator 15 generates a frame termination pulse, and the period meter 17 produces a voltage corresponding to the pitch period measured in the previous frame.

In the pauses and in the noise sections of speech, the key 23 through the circuit 22, to which the tone-to-detector signal 4 is supplied, disconnects the filter 24 from the input of the inverse transform unit 18.

The voltage at the output of the filter 24 decreases, and accordingly, the oscillation period of the controlled generator 15 tends to the lower boundary of the measured tones, since the corresponding voltage from the generator of the reference voltage 26 is supplied to it through the adder 25.

Subject invention

Claims (3)

1. An intonometer containing a compressor, the output of which is connected to the first input of the detector Tonchum and to the inputs of a series of series-connected band-pass filters and phasing units consisting of parallel-connected pulse generator connected via a controlled delay line to the input of the multiplier and meter amplitudes connected to another input of the multiplier, and the outputs of the multipliers are connected to the input of the adder, and containing a series-connected period meter and an inverse transform unit, In order to improve measurement accuracy, a minimum limiter is connected between the bandpass filters and the compressor, and the input of one of the phasing blocks is connected to the compressor output via a peak selector, the outputs of amplitude meters through an additional series-connected adder, pulse search unit, a controlled oscillator connected to the input of the period meter, the output of which is additionally connected to the control input the generator through the sensor of prior information, the output of the adder is connected to the second input of the pulse search unit, the outputs of the pulse shapers through the frame end detector are connected to the control inputs of the delay lines, as well as to the second input of the a priori information sensor, to the second input of the detector "Ton-noise, the third input of which is connected to the output of the additional adder, the output of the pulse search unit is connected to the fourth input, the output of the detector is tone-noise, connected to the fourth input sensor prior information, and the output of the controlled generator is connected to the input frame end detector and with the third sensor input of a priori information. 2. The intonometer according to claim 1, characterized in that the frame termination detector comprises an AND connected circuit multivibrator 3. The intonometer according to claim 1, wherein the a priori information sensor comprises an AND circuit, an electronic key, a low pass filter, and an adder, to the other input of which the reference voltage generator is CONNECTED. G, Exit T-sh VshhoZ aT. FIG. /