JPH04243324A - Automatic sound codec adjustment circuit - Google Patents

Abstract

PURPOSE:To automatically adjust an electronic variable resistor and to set the circuit to a specified transmission reception level by employing the electronic variable resistor for the resistor for level adjustment of a sound CODEC circuit and measuring the transmission reception level so as to generate a control data. CONSTITUTION:A 0dB digital pattern generated by a 0dB generating means 60 is inputted to a terminal Di of a sound CODEC 30 through a 1/3 selection means 70. Then an output level from a terminal Ao is measured by a measurement means 80, its output is monitored by a control means 90 and an automatic adjustment means 50 is adjusted automatically so that the output level at an output terminal 4WR reaches 0dB. Then a reference signal from the reference signal generating means 10 is inputted to a terminal Ai of the CODEC 30 through a 1/2 selection means 20. An output from a terminal Do is inputted to a terminal Di through the means 70 and an output from the terminal Ao is outputted via the means 50, measured by the means 80 and its output is monitored by the means 90. Then the transmission level automatic adjustment means 40 is adjusted automatically so that the output level of the terminal 4WR is 0dB.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit for automatically adjusting the transmission/reception level of an audio codec. In digital communications, for example, an analog signal input from a telephone, etc. is converted into a digital signal by an analog/digital conversion circuit called an audio codec in a multiplexer, and then sent out to a transmission path, and the digital signals input from the transmission path are the same. It is converted from digital to analog using an audio codec and sent to the telephone.

[0002] In such communication between terminals via a multiplexer, the level at each point is specified, and the level is adjusted for each audio codec circuit to match the specified level.

[0003] Such an audio codec circuit is required to be a circuit that can automatically adjust the level in order to shorten the time required for level adjustment as much as possible.

0004

2. Description of the Related Art FIG. 4 is a diagram illustrating a conventional example. In the figure, 30 is an audio codec that performs analog/digital and digital/analog conversion, 40B is an operational amplifier 41,
A transmission level adjustment circuit consisting of a resistor 42 and a variable resistor 43A, 50B is an operational amplifier 51, a resistor 52, and a variable resistor 53A
61 is a 0dB generator, 7 is a reception level adjustment circuit consisting of
1 is a 1/3 selector, T1 is a transmitting transformer, and T2 is a receiving transformer.

[0005] Ai and Ao of the audio codec 30 are analog input/output terminals, and Di and Do are digital input/output terminals. In the above circuit, first, the digital 1kHz, 0dB digital pattern generated by the 0dB generator 61 is input to Di of the audio codec 30 via the 1/3 selector 71, and the analog signal output from Ao is set to the receiving level. The signal is outputted to the output terminal 4WR through the adjustment circuit 50B and the reception transformer T2. At this time, output terminal 4
The variable resistor 53A is adjusted and fixed so that the output level of WR becomes 1 kHz and 0 dB.

Next, 1kHz, 0d is applied to the input terminal 4WS.
Input the B analog signal. This signal is inputted to Ai of the audio codec 30 through the transmission transformer T1 and the transmission level adjustment circuit 40B, converted into a digital signal, and outputted from Do.

This digital signal is sent to the 1/3 selector 71.
The analog signal inputted to Di of the audio codec 30 via Ao and outputted from Ao is input to a reception level adjustment circuit 50B,
It is output to the output terminal 4WR through the receiving transformer T2. At this time, the output level of output terminal 4WR is 1kHz, 0
The variable resistor 43A of the transmission level adjustment circuit 40B is adjusted and fixed so that the level becomes dB.

[0008]

When the above-mentioned conventional audio codec circuit is installed in, for example, a multiplexer, the level of transmission and reception is adjusted during testing of the multiplexer. Since audio codec circuits are installed to support lines, there are a large number of them, and their adjustment requires a large amount of man-hours.

The present invention aims to realize an audio codec automatic adjustment circuit that can accurately and automatically adjust the transmission and reception levels of the audio codec circuit.

0010

Means for Solving the Problems FIG. 1 is a block diagram illustrating the principle of the present invention. 10 in the figure is a reference signal generation means for generating a reference signal, and 20 is a 1/2 selection means for selecting either the signal generated by the reference signal generation means 10 or the signal inputted from the input terminal 4WS. , 30 performs analog/digital conversion and digital/digital conversion of audio signals.
This is an audio codec that performs analog conversion.

Further, 40 is a transmission level automatic adjustment means that is connected to the analog input terminal of the audio codec 30 and adjusts the transmission level, and 50 is a reception level automatic adjustment means that is connected to the analog output terminal of the audio codec and is used to adjust the reception level. 60 is a 0 dB generating means for generating a 0 dB digital pattern, 70 is a ⅓ selection means for selecting a digital input signal to the audio codec 30, and 80 is connected to the output terminal 4WR. 90 is a control means for controlling the automatic transmission level adjustment means 40 and the automatic reception level adjustment means 50 so that the output of the level measurement means 80 becomes a predetermined level; The reception level automatic adjustment means 50 is automatically adjusted by inputting the 0 dB digital pattern, and the transmission level adjustment means 40 is automatically adjusted using the reference signal generated by the reference signal generation means 10.

0012

[Operation] The 0 dB digital pattern generated by the 0 dB generating means 60 is inputted to the Di terminal of the audio codec 30 through the 1/3 selecting means 70, the output level from Ao is measured by the level measuring means 80, and the control means 90 monitors the output of the level measurement output 80, and automatically adjusts the reception level automatic adjustment means 50 so that the output level of the output terminal 4WR becomes 0 dB.

Next, the reference signal generated by the reference signal generating means 10 is inputted to the Ai terminal of the audio codec 30 through the 1/2 selection means 20, and the output from Do is inputted to the terminal Ai of the audio codec 30 through the 1/3 selection means 70. input to the terminal, and output the output from Ao through the reception level automatic adjustment means 50,
The output level is measured by the level measuring means 80, and the control means 90 monitors the output of the level measuring means 80, and automatically adjusts the automatic transmission level adjusting means 40 so that the output level of the output terminal 4WR becomes 0 dB. As a result, it is possible to obtain an audio codec automatic adjustment circuit that can automatically adjust transmission and reception levels.

[0014]

Embodiment FIG. 2 is a diagram illustrating an embodiment of the present invention. The embodiment shown in FIG. 2 is based on the reference signal generating means 1 explained in FIG.
0, a reference signal generator 11 that generates 1kHz and 0dB, and a 1/2 selector 2 as a 1/2 selection means 20.
1, an audio codec 30, and an automatic transmission level adjustment circuit 40A consisting of an operational amplifier 41, a resistor 42, and an electronic variable resistor 43 as an automatic transmission level adjustment means 40,
As the reception level automatic adjustment means 50, an operational amplifier 51,
1 as a receiving level automatic adjustment means 50A consisting of a resistor 52 and an electronic variable resistor 53, and a 0 dB generating means 60;
kHz, 0dB that generates a 0dB digital pattern
a generator 61, a 1/3 selector 71 as a 1/3 selection means 70, a level meter 81 as a level measurement means 80,
The control means 90 includes a control circuit 91 and a reception memory circuit 9.
2, a transmission memory circuit 93, and a transmission transformer T1,
This is an example configured from a receiving transformer T2.

First, the 1kHz generated by the 0dB generator 61
z, 0dB digital pattern 1/3 selector 71
input to the Di terminal of the audio codec 30 through the A
Measure the output from the o terminal at output terminal 4WR. The measurement data of the level meter 81 is input to the control circuit 91, and the control circuit 91 creates control data based on the measurement data of the level meter 81. The electronic variable resistor 53 is automatically controlled. The control data at this time is stored in the reception storage circuit 92.

Next, the reference signal generator 11 generates 1
A kHz, 0 dB analog signal is input to the Ai terminal of the audio codec 30, the output from the Do terminal is input to the Di terminal of the audio codec 30 through the 1/3 selector 71, and the output from the Ao terminal is input to the output terminal 4WR. Measure with. The measurement data of the level meter 81 is input to the control circuit 91,
The control circuit 91 creates control data based on the measurement data of the level meter 81, and automatically controls the electronic variable resistor 43 of the automatic transmission level adjustment circuit 40A via the transmission storage circuit 93. The control data at this time is stored in the transmission memory circuit 9.
Store in 3.

The measurement data of the level meter 81 is input as digital data to the control circuit 91, and the control circuit 91 creates control data so that the measurement result is 0 dB and sends it to the electronic variable resistors 43 and 53. There is. By performing level measurement and control digitally in this manner, it becomes possible to perform accurate and automatic measurement.

FIG. 3 shows another embodiment of the invention. In the embodiment shown in FIG. 2, the reference signal generator 11 and the level meter 81 are mounted on a printed board unit for line support, but in FIG. 3, the reference signal generator 11,
This is an example in which a general-purpose measuring device such as the PCM measuring device 100A is used as the level meter 81, and it is possible to simplify the configuration of the printed board unit on which the audio codec circuit is mounted.

[0019]

According to the present invention, the resistance for level adjustment of the audio codec circuit is an electronic variable resistor, the transmission and reception level of the audio codec circuit is measured, and control data is created from the results. It is possible to realize an audio codec automatic adjustment circuit that can automatically adjust the resistance and set a specified transmission/reception level.

[Brief explanation of the drawing]

[Figure 1] Block diagram explaining the principle of the present invention

[Figure 2
] Diagram explaining an embodiment of the present invention

[Figure 3] Diagram explaining other embodiments of the present invention

[Figure 4] Diagram explaining a conventional example

[Explanation of symbols]

10 Reference signal generation means 1
1 Reference signal generator 20 1/2 selection means
21 1/2 selector 30 Audio codec
40 Transmission level automatic adjustment means 40A Transmission level automatic adjustment circuit 40B
Transmission level adjustment circuit 41, 51 Operational amplifier 4
2, 52 Resistor 43, 53 Electronic variable resistor
43A, 53A Variable resistor 50 Reception level automatic adjustment means 50A
Reception level automatic adjustment circuit 50B Reception level adjustment circuit 60
0dB generation means 61 0dB generator
70 1/3 selection means 71 1/3 selector
80 Level measuring means 81 Level meter
90 Control means 91 Control circuit
92 Memory circuit for reception 93 Memory circuit for transmission
100A PCM measuring instrument T1 Transmission transformer
T2 receiving transformer

Claims (2)

[Claims] 1. A circuit that automatically adjusts the transmission/reception level of an audio codec, the circuit comprising a reference signal generating means (10) for generating a reference signal, and the reference signal generating means (10).
1/2 selection means (20) for selecting either the signal generated at 0) or the signal input from the input terminal (4WS);
an audio codec (30) that performs analog/digital conversion and digital/analog conversion of audio signals; an automatic transmission level adjustment means (40) that is connected to the analog input terminal of the audio codec 30 and adjusts the transmission level; Reception level automatic adjustment means (5) connected to the analog output terminal of the codec 30 and adjusting the reception level.
0), 0dB generation means (60) for generating a 0dB digital pattern, 1/3 selection means (70) for selecting a digital input signal to the audio codec (30), and an output terminal (4WR). level measuring means (8
0), and the transmission level automatic adjustment means (40) so that the output of the level measurement means (80) becomes a predetermined level.
and a control means (90) for controlling the reception level automatic adjustment means (50). 2. An audio codec (30) that performs analog/digital conversion and digital/analog conversion of audio signals; and automatic transmission level adjustment means (40) that is connected to the analog input terminal of the audio codec 30 and adjusts the transmission level. ), automatic reception level adjustment means (50) connected to the analog output terminal of the audio codec 30 and adjusting the reception level, 0dB generation means (60) for generating a 0dB digital pattern, and the audio codec (30). 1/3 selection means (70) for selecting a digital input signal to the output terminal (4WR);
) and a control means (90) for controlling the automatic reception level adjustment means (50), the control means (90) controls the automatic transmission level adjustment means (40) and the automatic reception level adjustment means (50). , a tester (100) having a reference signal generator (11) and a level meter (81).
) Audio codec automatic adjustment circuit.