JPH05284064A - Automatic equalizer for cable line amplitude characteristic - Google Patents

Abstract

PURPOSE:To provide satisfactory speaking by automatically equalizing the cable line amplitude characteristic of a line exclusive for analog telephone at the time of no speaking. CONSTITUTION:A digital control cable line amplitude characteristic equalizer EQL is controlled by a control part CONT with memory. A voltage comparator COMP compares the rectified voltage of high frequency signals with the rectified voltage of low frequency signals, inputs the result to the CONT, operates an automatic control loop so that those voltages can be equal at all times, and holds a control value at the time of preceding no speaking at the time of speaking.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for automatically equalizing the cable line amplitude characteristic of an analog telephone dedicated line.

[0002]

2. Description of the Related Art There has been no conventional device for automatically equalizing the amplitude characteristic of a cable line in an analog telephone dedicated line when there is no call.

[0003]

DISCLOSURE OF THE INVENTION The present invention is a cable line that performs automatic equalization by utilizing a no-call time zone of a dedicated line and maintains the equalization characteristic during a call so that a good call can be made. An object is to provide an amplitude characteristic automatic equalizer.

[0004]

To achieve the above object, an automatic equalizer for a cable line amplitude characteristic of the present invention is provided with a digital control cable line amplitude characteristic equalizer and a control unit with a memory, and a callless communication Sometimes, the automatic control is activated so that the rectified voltage of the high-group frequency signal and the rectified voltage of the low-group frequency signal at the output point are always equal, and the control value during the immediately preceding non-call is maintained during the call. is there.

[0005]

In the cable line amplitude characteristic automatic equalizer configured as described above, two signals having different frequencies are sent to the cable line at the same level when no call is made, and at the output point of the equalizer on the receiving side, By making these two signals the same level again, the intended purpose is achieved.

[0006]

EXAMPLES Examples will be described with reference to the drawings.
In FIG. 1, the digital control cable line amplitude characteristic equalizer EQL is controlled by the memory-equipped control unit CONT. The voltage comparator COMP compares the rectified voltage of the high group frequency signal with the rectified voltage of the low group frequency signal and inputs the result to CONT to form an automatic control loop.

[0007]

Since the present invention is configured as described above, it is possible to maintain the automatic equalization characteristic during a non-call even during a call and obtain a good call.

[Brief description of drawings]

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

[Explanation of symbols]

 EQL Digital control cable Line amplitude characteristic equalizer CONT Control unit with memory BPF1, BPF2 Bandpass filter RC1, RC2 Rectifier COMP Voltage comparator IN input terminal OUT output terminal

Claims (1)

[Claims] 1. A digital control cable line amplitude characteristic equalizer and a controller with memory are provided so that the rectified voltage of a high group frequency signal and the rectified voltage of a low group frequency signal at an output point are always equal to each other when there is no call. An automatic equalizer for cable line amplitude characteristics, which activates automatic control and holds the control value when there is no call immediately before the call.