JPH04948A - Speech characteristic device of telephone set for digital line - Google Patents

Abstract

PURPOSE:To eliminate an influence of the degradation in frequency characteris tic of a telephone set for digital line by providing three digital filters and meas uring characteristics of the transmission side, the reception side, and the sidetone side of a handset and adjusting digital filters based on results of this measure ment. CONSTITUTION:First, second, and third filters 32, 33, and 31 are provided be tween an A/D converter 23 and a line interface 40, between the line interface 40 and a D/A converter 24, and between the A/D converter 23 and the D/A converter 24 respectively, and outputs of second and third filters 33 and 31 are added by a digital adder 34 and the result is sent to the D/A converter 24. Characteristics of the transmission side, the reception side, and the sidetone side of a handset 21 are measured, and first to third fitters 31 to 33 are adjusted based on results of this measurement. Thus, frequency characteristics are real ized by digital filters 31 to 33 and are automatically set.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a speech characteristics device for a digital line telephone that measures and sets the speech characteristics of a digital line telephone.

[Conventional technology]

Conventionally, the call characteristics of digital line telephones are based on the calling side,
The characteristics of the receiving side and the sidetone side are each measured, and based on the difference between the results and the desired frequency characteristics, an analog filter is designed to compensate for the difference, and is placed between the handset, A/D converter, and D/A converter. This is achieved by making analog adjustments based on the results of designing the characteristics of the amplifier.

[Problem to be solved by the invention]

The communication characteristics of the digital line telephone described above are realized by adjusting the values of capacitors, resistors, etc. in the amplifier to obtain a desired difference in frequency characteristics. Therefore, when realizing the communication characteristics of a digital line telephone, it is difficult to design analog filters, etc., and the characteristics of the filter change due to aging of capacitors, resistors, etc., resulting in a disadvantage that the characteristics deviate from the desired characteristics.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a speech characteristic device for a digital line telephone that can eliminate such drawbacks, realize frequency characteristics using a digital filter, and automatically set the characteristics.

[Means to solve the problem]

The present invention provides a handset having a transmitting acoustic transducer element and a receiving acoustic converting element, a transmitting amplifier for amplifying a signal from the transmitting acoustic converting element in the handset, and a transmitting amplifier for amplifying a signal from the transmitting acoustic transducer element in the handset. An A/D converter for converting an analog signal into a digital signal, a line interface circuit for sending the output of this A/D converter to a telephone line and extracting a received signal from among the signals from the line, and this line. a D/A converter that converts a digital signal from an interface circuit or other digital source into an analog signal; a receiver amplifier that amplifies the output of the D/A converter and sends it to a receiver acoustic transducer in the handset; a pseudo mouth that is coupled to a sound transducing element for speech in the handset by acoustic means and transmits a sound pressure that approximates the sound pressure around the actual lips in response to an input electrical signal; A speech characteristic device for a digital line telephone comprising a pseudo ear coupled to an acoustic transducer by acoustic means, designed to approximate the impedance of an ear, and converting an input acoustic signal into an electrical signal. a first circuit between the A/D converter and the line interface circuit that digitally filters the output of the A/D converter;
a second filter that is located between the line interface circuit and the D/A converter and digitally filters the output of the line interface circuit; and a second filter that digitally filters the output of the line interface circuit; a third filter located in between that digitally filters the output of the A/D converter; and adding the outputs of the second filter and the third filter and sending the result to the D/A converter. a digital adder, and measures the characteristics of the transmitting side, the receiving side, and the side tone side of the handset, and based on the measurement results, the characteristics of the first. and an adjustment section that adjusts the second and third filters.

In the present invention described above, the adjustment section includes a first frequency characteristic measurement circuit that measures the frequency characteristics from the artificial mouth to the A/D converter, and a first frequency characteristic measurement circuit that measures the frequency characteristics from the D/A converter to the artificial ear. a second frequency characteristic measuring circuit for measuring the frequency characteristic, a third frequency characteristic measuring circuit for measuring the frequency characteristic from the artificial mouth to the artificial ear, and a predetermined frequency characteristic of the transmitting side. A transmitting standard characteristic section, a receiving standard characteristic section in which a predetermined frequency characteristic on the receiving side is recorded, and a sidetone standard characteristic section in which a predetermined sidetone side frequency characteristic is recorded, Comparing the frequency characteristics of the first frequency characteristic circuit and the transmitting reference characteristic section and calculating the difference thereof, and comparing the frequency characteristics of the second frequency characteristic circuit and the receiving reference characteristic section and calculating the difference. a frequency characteristic comparison circuit that calculates a difference by comparing the frequency characteristics of the third frequency characteristic circuit and the sidetone reference characteristic section; It is preferable to include a filter constant calculation circuit for calculating filter constants for the second and third filters.

Furthermore, in the present invention described above, the adjustment section, on the transmitting side, measures the frequency characteristics from the pseudo mouth to the A/D converter with the first frequency characteristic measurement circuit, and compares the results with the frequency characteristics. The difference between the transmitting reference characteristics of the transmitting reference characteristic section is calculated by the frequency characteristic comparison circuit, and the desired characteristic of the first filter is calculated by the filter constant calculating circuit, and at the same time, the calculation result is sent to the first filter. Substitute,
On the receiving side, the frequency characteristic from the D/A converter to the pseudo device is measured by the second frequency characteristic measuring circuit, and the difference between the result and the reception reference characteristic of the reception reference characteristic section is calculated as the frequency characteristic. calculating a desired characteristic of the third filter using a characteristic comparing circuit, and simultaneously calculating a desired characteristic of the third filter using the filter constant calculating circuit, and assigning the calculated result to the second filter;
On the side sound side, the characteristics of the third filter are set to pass through without loss, and then the frequency characteristics from the artificial mouth to the artificial tool are measured by the frequency characteristic measuring circuit. The difference between the result and the sidetone reference characteristic of the sidetone reference characteristic section is calculated by the frequency characteristic comparison circuit, and the desired characteristic of the third filter is calculated by the filter constant calculation circuit, and at the same time, the difference is calculated by the third filter. By substituting the results, it is preferable to determine the speech characteristics regarding the frequency characteristics of the digital line telephone.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

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

The call characteristic device for a digital line telephone shown in FIG. .

The dummy part 10 includes a dummy mouth 11 and a dummy tool 12.

The telephone unit 20 includes a handset 21 including a transmitting acoustic transducer 21A and a receiving acoustic transducer 21B, a transmitting amplifier 22, and an A/D (Analog-to-Di)
digital) converter 23, and D/A (Digital) converter 23,
an i tal-to-Analog) converter 24;
A receiving amplifier 25 is also provided.

The filter section includes filters 31, 32, 33 and a digital adder 34.

The measuring section 50 includes frequency characteristic measuring circuits 51, 52, 53, a transmitting reference characteristic section 54, a receiving reference characteristic section 55, and a sidetone reference characteristic section 56.

The calculation unit 60 includes a frequency characteristic comparison circuit 61 and a filter constant calculation circuit 62.

In such a call characteristic device for a digital line telephone, the pseudo mouth 11 of the pseudo image unit 10 is provided with an input terminal B,
The dummy device 12 sends out a sound pressure that approximates the actual sound pressure around the lips in response to the input electrical signal, and is equipped with an output terminal A, designed to approximate the impedance of the ear, and transmits the input sound pressure. Convert a signal into an electrical signal. Further, the pseudo mouth 11 and the pseudo tool 12 are each coupled by acoustic means to the handset 20, which has a transmitting acoustic transducing element 21A and a receiving acoustic transducing element 21B.

The transmitting amplifier 22 of the telephone section 20 amplifies the electrical signal from the transmitting acoustic transducer 21A of the handset 21.

The A/D converter 23 converts the analog signal from the transmitting amplifier 22 into a digital signal and sends it to the filter section 30. An output terminal is provided on the output side of the A/D converter 23.

The D/A converter 24 includes an input terminal C and converts the digital signal from the filter section 30 into an analog signal.

The receiving amplifier 25 amplifies the analog signal from the D/A converter 24 and sends it to the receiving acoustic conversion element 21B of the handset 21.

The filter 31 of the filter section 30 is connected to the A/D converter 2
The digital signal from 3 is digitally filtered and sent to a digital adder 34.

The filter 32 digitally filters the digital signal from the A/D converter 23 and sends it to the line interface 40 .

Filter 33 digitally filters the digital signal from line interface 40 and sends it to digital adder 34 .

Digital adder 34 adds the digital signal of filter 31 to the digital signal of filter 33 and sends the result to D/A converter 24 .

The line interface 40 sends the output of the filter 32 to the telephone line 70 , and extracts the received signal from the signal from the line 70 and sends it to the filter 33 .

The frequency characteristic measurement circuit 51 of the measurement section 50 has an input terminal D1
and output terminals Bl and XI, and A/
Measure the frequency characteristics up to the D converter 23.

The transmitting reference characteristic section 54 includes an output terminal Y1, and records predetermined frequency characteristics on the transmitting side.

The frequency characteristic measuring circuit 52 includes an input terminal A2 and output terminals C2 and χ2, and measures the frequency characteristic from the D/A converter 24 to the artificial ear 12.

The reception reference characteristic 55 includes an output terminal Y2 and records predetermined frequency characteristics on the reception side.

The frequency characteristic measurement circuit 53 has an input terminal A3 and an output terminal B3. X3, and measures the frequency characteristics from the pseudo mouth 11 to the pseudo ear 12.

The sound measurement reference characteristic 56 includes an output terminal Y3 and records a predetermined sound measurement side frequency characteristic.

The frequency characteristic comparison circuit 61 of the calculation unit 60 has an input terminal X.

Y, the frequency characteristics of inputs applied between these two terminals are compared and the difference characteristics are calculated.

The filter constant calculation circuit 62 includes a frequency characteristic comparison circuit 61
A filter constant for filter 31, filter 32, or filter 33 is calculated from the output result.

Next, the operation of the call characteristic device for this digital line telephone will be explained.

When measuring and setting the transmission characteristics, connections are made as shown in FIG. That is, the output terminal Bl is an analog type and the input terminal D1 is a digital type, and the output terminal B1 of the frequency characteristic measurement circuit 51 that measures the transfer characteristic between two points is connected to the input terminal B of the pseudo port 11, and the A/D Connect the output terminal of the converter 23 to the input terminal D1 of the frequency characteristic measurement circuit 51,
The output terminal X1 of the frequency characteristic measurement circuit 51 that outputs the measurement results is connected to one input terminal X of the frequency characteristic comparison circuit 61,
The frequency characteristic comparison circuit 6 connects the output terminal Y1 of the transmitting reference characteristic section 54, which records predetermined characteristics of the transmitting side, to the frequency characteristic comparison circuit 6.
The output FO of the filter constant calculation circuit 62 is connected to the other input terminal Y of the filter 32, respectively.

After these connections, the A/D converter 2 is connected from the pseudo port 11.
The frequency characteristics up to 3 are measured by the frequency characteristic measuring circuit 51, and the difference between the result and the transmitting reference characteristic of the transmitting reference characteristic section 54 is calculated by the frequency characteristic measuring circuit i61, and the desired characteristic of the filter 32 is determined by the filter constant. By sending the calculation result to the filter 32 at the same time as calculation by the calculation circuit 62, the frequency characteristics of the filter 32 are transmitted from the pseudo mouth 11 to the transmitting acoustic conversion element 21A of the handset 21, the transmitting amplifier, and the A/D.
It has a characteristic that is the difference between the frequency characteristic up to the converter 22 and the transmitting reference characteristic, and therefore the frequency characteristic from the pseudo input port 11 to the line interface circuit 40 is the same as the transmitting reference characteristic.

When measuring and setting the reception characteristics, connections are made as shown in FIG. That is, the output terminal C2 is a digital type and the input terminal A2 is an analog type, and the output terminal C2 of the frequency characteristic measurement circuit 52 that measures the transfer characteristic between two points is connected to the D/A.
Connecting the output terminal A of the pseudo ear 12 to the input terminal C of the converter 24 and the input terminal A2 of the frequency characteristic measurement circuit 52,
The output terminal X2 of the frequency characteristic measurement circuit 52 that outputs the measurement results is connected to one input terminal X of the frequency characteristic comparison circuit 61,
The frequency characteristic comparison circuit 6 connects the output terminal Y2 of the reception reference characteristic section 55, which records the characteristics of the reception side determined in advance, to the frequency characteristic comparison circuit 6.
The output Fl of the filter constant calculation circuit 62 is connected to the other input terminal Y of the filter 33, respectively.

After these connections, the data from the D/A converter 24 to the pseudo ear 1 is
The frequency characteristics up to 2 are measured by the frequency characteristic measuring circuit 52, the difference between the result and the receiving standard characteristic of the receiving standard characteristic section 55 is calculated by the frequency characteristic comparing circuit 61, and the desired characteristic of the filter 33 is calculated by the filter constant calculating circuit. By sending the calculation result to the filter 33 at the same time as the calculation in 62, the frequency characteristics of the filter 33 are adjusted from the D/A converter 24 to the receiving amplifier 25, the receiving acoustic conversion element 21B of the handset 21, and the artificial ear 12. It has the characteristic of the difference between the frequency characteristic and the reception reference characteristic, and therefore the line interface circuit 4
The frequency characteristics from 0 to the pseudo ear 12 are the same as the reception reference characteristics.

When measuring and setting sidetone characteristics, connections are made as shown in FIG. That is, the output terminal B3 is of an analog type, the input terminal A3 is of an analog type, and the output terminal B3 of the frequency characteristic measurement circuit Wi53 for measuring the transfer characteristic between two points is connected to the input terminal B of the artificial mouth 11, and the artificial ear 12 The output terminal A of the frequency characteristic measurement circuit 530 is connected to the input terminal A3, and the output terminal X3 of the frequency measurement circuit 53 that outputs the measurement result is connected to one input terminal X of the frequency characteristic comparison circuit 61. A side tone reference characteristic section 56 in which side characteristics are recorded.
The output terminal ¥3 of the filter constant calculation circuit 61 is connected to the other input terminal Y of the frequency characteristic comparison circuit 61, and the output FS of the filter constant calculation circuit 62 is connected to the filter 31.

After that, the characteristics of the filter 31 are set to pass through without loss, and the frequency characteristics from the artificial mouth 11 to the artificial part 12 are measured by the frequency characteristic measuring circuit 53, and the result and the side sound reference characteristic part 56 are measured. The difference between the sidetone reference characteristics is calculated by the frequency characteristic comparison circuit 61, and the desired characteristic of the filter 31 is calculated by the filter constant calculation circuit 62.
1 to change the frequency characteristics of the filter 310. Digital adder 34 adds power to the outputs of filters 31 and 33 and sends them to D/A converter 24 . By changing the frequency characteristics of the filter 31, the transmitting acoustic transducer 2 of the handset 21 can be
1A, transmitting amplifier 22, A/D converter 23, D/A
The frequency characteristics from the pseudo mouth 11 to the pseudo section 12, which are related to the converter 24, the receiver amplifier 25, and the receiver acoustic conversion element 21B of the handset 21, are the same as the sidetone reference characteristics.

(Effects of the Invention) As explained above, according to the present invention, it is possible to eliminate the influence of deterioration of frequency characteristics on the call characteristics of a digital line telephone, and the characteristics of each part can be easily set. There is.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing measurement of transmission characteristics and filter settings in the embodiment of FIG. 1, and FIG. FIG. 4 is a diagram showing measurement of sidetone characteristics and filter setting in the embodiment of FIG. 1. FIG. 10... Pseudo part 11... Pseudo mouth 12... 20... 21... 21A... 21B... 22... 23... 24... 25... 30・ ・ ・ 31～33・ 34・ ・ 40・ ・ 50・ ・ 51～53・ 54・ ・ ・ 55・ ・ 56・ ・ ・ 60・ ・ ・ 61・ ・ ・ Pseudo part telephone part handset transmission Acoustic conversion element for speech Acoustic conversion element for reception Transmission amplifier A/D converter D/A converter Receiving amplifier Filter section Filter Digital adder Line interface measurement section Frequency characteristic measurement circuit Transmission reference characteristic section Reception reference characteristic section Sidetone reference characteristic Calculation section frequency characteristic comparison circuit 62...Filter constant comparison circuit

Claims (3)

[Claims] (1) A handset having a transmitting acoustic conversion element and a receiving acoustic conversion element, a transmitting amplifier for amplifying the signal from the transmitting acoustic converting element in the handset, and an analog signal from the transmitting amplifier. An A/D converter for converting a signal into a digital signal, a line interface circuit for sending the output of this A/D converter to a telephone line and extracting a received signal from among the signals from the line, and this line interface. a D/A converter that converts a digital signal from a circuit or other digital source into an analog signal; a receiver amplifier that amplifies the output of the D/A converter and sends it to a receiver acoustic transducer in the handset; a pseudo mouth that is coupled by acoustic means to a sound transducing element for speech in the handset and transmits a sound pressure that approximates the sound pressure around the actual lips in response to an input electrical signal; and a sound for speech in the handset. A speech characteristic device for a digital line telephone comprising a pseudo ear coupled to a conversion element by acoustic means, designed to approximate the impedance of the ear, and converting an input acoustic signal into an electrical signal, a first filter that is located between the /D converter and the line interface circuit and digitally filters the output of the A/D converter; and a first filter that is located between the line interface circuit and the D/A converter and that filters the output of the A/D converter; a second filter that digitally filters the output of the circuit; and a third filter that is located between the A/D converter and the D/A converter and that digitally filters the output of the A/D converter. a digital adder that adds the outputs of the second filter and the third filter and sends the result to the D/A converter; and characteristics of the transmitting side, the receiving side, and the sidetone side of the handset. 1. A speech characteristic device for a digital line telephone, comprising: an adjustment section that measures the first, second, and third filters based on the measurement results. (2) The speech characteristic device for a digital line telephone according to claim 1, wherein the adjustment section includes: a first frequency characteristic measuring circuit that measures the frequency characteristic from the artificial port to the A/D converter; a second frequency characteristic measuring circuit that measures the frequency characteristic from the /A converter to the artificial ear, and a third frequency characteristic measuring circuit that measures the frequency characteristic from the artificial mouth to the artificial ear; A transmitting reference characteristic section that records the frequency characteristics of the transmitting side, a receiving standard characteristic section that records the predetermined frequency characteristics of the receiving side, and a predetermined frequency characteristic of the sidetone side. Compare the frequency characteristics of the sidetone reference characteristic section which has been set, and the frequency characteristics of the first frequency characteristic circuit and the transmitting reference characteristic section to calculate the difference, and calculate the difference between the sidetone reference characteristic section and the receiving reference characteristic section. a frequency characteristic comparison circuit that compares the frequency characteristics of the third frequency characteristic circuit and the sidetone reference characteristic section and calculates the difference thereof, and compares the frequency characteristics of the third frequency characteristic circuit and the sidetone reference characteristic section and calculates the difference; and a filter constant calculation circuit for calculating filter constants for the first, second, and third filters from the output results. (3) In the speech characteristic device for a digital line telephone according to claim 2, the adjustment section, on the transmitting side, adjusts the frequency characteristic from the pseudo port to the A/D converter to the first frequency. The frequency characteristic comparison circuit calculates the difference between the result and the transmission reference characteristic of the transmission reference characteristic section, and the desired characteristic of the first filter is calculated by the filter constant calculation circuit. At the same time, the calculation result is substituted into the first filter, and on the receiver side, the frequency characteristic from the D/A converter to the artificial ear is measured by the second frequency characteristic measurement circuit, and the result and the Calculating the difference between the reception reference characteristics of the reception reference characteristic section with the frequency characteristic comparison circuit, calculating the desired characteristics of the third filter with the filter constant calculation circuit and simultaneously substituting the calculation result into the second filter; On the sidetone side, the characteristics of the third filter are set to pass through without loss, and then the frequency characteristics from the artificial mouth to the artificial ears are measured by the frequency characteristic measurement circuit, and The difference between the result and the sidetone reference characteristic of the sidetone reference characteristic section is calculated by the frequency characteristic comparison circuit, and the desired characteristic of the third filter is calculated by the filter constant calculation circuit, and at the same time, the difference is calculated by the third filter. By substituting the results, the speech characteristics regarding the frequency characteristics of the digital line telephone are determined.