JPH0637733A - Voice detector - Google Patents

Abstract

PURPOSE:To prevent the deterioration in a compression rate of a DSI equipment by discriminating an inputted PCM signal to be in a non-voice block when a fault signal is received. CONSTITUTION:This detector is provided with a voice detection section consisting of a band pass filter 1 detecting whether an inputted PCM signal 101 corresponds to a voiced block or a non-voice block, of a zero cross calculation section 2 and a power calculation section 4, with a comparator section 8 comparing the PCM signal 101 with a fault pattern and outputting a coincidence/dissidence signal, with a fault pattern storage section 9 generating the fault pattern, with a counter section 6 generating a signal representing a fault block or a usual block based on an output signal from the comparator section 8, with a delay section 5 delaying a detection signal of the voice detection section by the number of a sampling period required to detect the fault block, and with a discrimination section 7 receiving an output signal of the delay section 5 and an output signal of the counter section, and outputting the output of the delay section 5 as it is when the output of the counter section 6 indicates the usual block and outputting the signal of the non-vice block as an output signal 102 when the output of the counter section 6 indicates the fault block.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voice detector, and more particularly to a highly efficient transmission system DSI (Digital Speech).
PC used for the Interpolation device
The present invention relates to a voice detector that detects the voice of an M signal.

[0002]

2. Description of the Related Art Conventionally, this type of voice detector has a structure shown in FIG. FIG. 2 is a block diagram of a conventional example. The input PCM signal 101 passes through the band pass filter 13 and the direct current component is cut, and the zero crossing number calculation unit 2 and the power value calculation unit 4
Entered in and. The determination unit 3 detects whether the input PCM signal 101 is in a voiced section or a silent section based on the input signals such as the number of zero crossings and the input amplitude, and outputs the output signal 102.

The DSI device in which the voice detector is used is a device for improving the utilization efficiency of the transmission line by sending only the voiced section of the PCM signal on the transmitting side to the opposite station. The voice detector is the PCM signal. Is for detecting the voiced section of.

[0004]

In the conventional voice detector, when a continuous signal of "11111111" which is a disturbance signal of the 64 Kbit / s channel of the PCM signal is received, the DC component is removed by the band pass filter. However, if the DC removal capability is not sufficient, there is a problem that it is detected as a sound part. Further, even when detecting silence, there is a problem that it takes time to detect a silence portion due to the response time of the filter.

Therefore, when this voice detector is used in a DSI device, there is a problem that the compression rate by DSI is lowered.

[0006]

The voice detector of the present invention comprises:
A bandpass filter that inputs a PCM signal and cuts a direct current component, a zero-crossing calculation unit that calculates the number of zero-crossings of the output signal of the bandpass filter, and a power value calculation that calculates the power of the output signal of the bandpass filter. A first determining unit that detects whether the PCM signal is voiced or silent from output signals of the zero-crossing calculation unit and the power value calculation unit.
A comparison unit that compares the PCM signal with a predetermined failure pattern of the PCM channel and outputs a match and mismatch signal, a failure pattern storage unit that stores the failure pattern of the PCM channel, and an output signal of the comparison unit A counting section that generates a signal that is regarded as a fault section when a coincidence signal is continuously output for a pre-specified number of samples and a normal section when the output of this comparison section is discontinuous for a pre-specified number of samples. A delay unit that delays the detection signal of the determination unit by a predetermined number of samples required to detect the faulty section, and the counting unit that receives the output signal of the delay unit and the output signal of the counting unit as input When the output of the delay section indicates a normal section, the output signal of the delay section is passed as it is, and when the output of the delay section indicates a failure section, the output of the delay section is output as a signal of a silent section. And a second determination unit for.

[0007]

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of this embodiment.

The bandpass filter 1 for inputting the PCM signal 101 and cutting the direct current component, the zero-crossing calculation unit 2 for calculating the number of zero-crossings of the output signal of the bandpass filter 1, and the power of the output signal of the bandpass filter are calculated. Power value calculation unit 3 for calculation
A determination unit 3 for detecting whether the PCM signal is voiced or silent based on the output signals of the zero-crossing calculation unit 2 and the power value calculation unit 3, and the PCM signal 101 and a predetermined P
The comparison unit 8 that compares the failure pattern of the CM channel and outputs a match and mismatch signal, the failure pattern storage unit 9 that stores the failure pattern of the PCM channel, and the failure section and the normal section from the output signal of the comparison section 8 A counting unit 6 that generates a signal shown in the figure, a delay unit 5 that delays the detection signal of the determination unit 3 by a predetermined number of samples required to detect a faulty section, an output signal of the delay unit 5, and a counting unit 6 When the output of the counting section 6 indicates a normal section, the output signal of the delay section 5 is allowed to pass as it is, and when the output indicates a fault section, the output of the delay section 5 is output as a signal of a silent section. 3 and 3.

Next, the operation will be described. The voice detection unit including the bandpass filter 1, the zero-crossing calculation unit 2, the power value calculation unit 4, and the determination unit 3 is the same as that in FIG.
The presence or absence of sound in the signal 101 is detected. The comparison unit 8 compares the input PCM signal 101 with the signal from the failure pattern storage unit 9 (“111111” in the case of a 64 Kbit / s PCM channel failure signal) to determine whether they match or do not match. The counting unit 6 counts the coincidence and non-coincidence, and when the coincidence signal is continuously received for the number of PCM samples designated in advance, the counting section 6 determines the faulty section.

If the output of the comparison unit 8 does not match the number of PCM samples designated in advance, the interval is set to a normal interval. In other cases, the output is not changed. For example, in the case of 5 consecutive sample numbers of coincidence signals, the fault interval is switched to, and in the case of 5 consecutive sample disagreement signals, switching to the normal period. The delay unit 5 uses this predesignated P
The output of the determination unit 3 is delayed by the number of 5 CM samples. That is, by delaying the output of the determination unit 3 by the time required to detect the failure pattern, erroneous detection of the determination unit 3 at the start of reception of the failure pattern is prevented. The determination unit 7 outputs the output of the determination unit 3 as the output signal 101 as it is, when the output of the counting unit is the faulty section, the output is the silent section.

The voice detection unit of the present invention is a DSP (Digit).
It is easily realized by using an al Signal Processor).

[0012]

As described above, according to the present invention, by having the fault pattern detecting section in addition to the voice detecting section,
It is possible to reliably and quickly detect a failure pattern and output an output signal of voice detection as a silent section. As a result, when the present voice detector is used in a DSI device, there is an effect of preventing a reduction in the DSI compression rate that occurs when a line failure occurs.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional example.

[Explanation of symbols]

 1 band pass filter 2 zero crossing calculation unit 3 determination unit 4 power value calculation unit 5 delay unit 6 counting unit 7 determination unit 8 output terminal 8 comparison unit 9 fault pattern storage unit

Claims (1)

[Claims] 1. A bandpass filter for inputting a PCM signal and cutting a direct current component, a zero-crossing calculation unit for calculating the number of zero-crossings of the output signal of the bandpass filter, and a power of the output signal of the bandpass filter. A power value calculating section for calculating; a first determining section for detecting whether the PCM signal is voiced or silent based on the output signals of the zero-crossing calculating section and the power value calculating section; and the PCM signal. Is compared with a predetermined failure pattern of the PCM channel and outputs a match and mismatch signal, a failure pattern storage section that stores the failure pattern of the PCM channel, and an output signal of the comparison section is designated in advance. If the coincidence signal is output continuously for a certain number of samples, it is regarded as a faulty section, and if the output of this comparison unit is a disagreement for a predetermined number of samples, it is regarded as a normal section. Signal generating unit, a delay unit delaying the detection signal of the determination unit by a predetermined number of samples necessary for detecting the faulty section, an output signal of the delay unit and an output signal of the counting unit. And a second determination unit which outputs the output signal of the delay unit as it is when the output of the counting unit indicates a normal section and outputs the output of the delay unit as a signal of a silent section when indicating an obstacle section. A voice detector characterized by comprising.