RU2100908C1 - Analog-to-digital and digital-to-analog converter of telephone signals - Google Patents

Abstract

FIELD: telephone equipment, in particular, interface between digital and analog phone exchange systems in city, long-distance and international networks. SUBSTANCE: device has n interface and encoding units 1.1-1.n, group receiver 2 of linear signals, re-coding unit 3, digital line 4, unit 5 for detection and input of service channels, control unit 6, oscillator unit. EFFECT: possibility to send service (linear) signals. 1 dwg

Description

 The invention relates to telephony, in particular, devices for converting telephone signals used on intra-area and long-distance communication with the transmission of signaling signals (linear signals) via dedicated digital service channels.

Known devices for temporary compaction and decompression with the input and output signals containing decoding blocks, a timer generator and a tone generator [1]
The specified device installed on the terminal stations matches the analog subscriber lines with a digital telephone exchange, and since linear signals are not used in the subscriber lines, the specified device does not allow coordinating the operation of the analog and digital telephone exchanges.

 Known digital stations and connecting equipment containing modulators, demodulators, a multiplexer and a computing unit (US patent N 3692941 H 04 J 3/08 1972). The specified device allows you to coordinate the work of two different digital telephone exchanges and can not work with analog signals.

Known communication systems with temporary compression, containing blocks for combining and separating signals, a computing unit, a data highway and a ring of ringing signals [2]
The closest in technical essence to the proposed device is a temporary compaction device with input and output of analog signals, containing encoders-decoders connected to a multiplexer, and a master oscillator connected to encoders-decoders and a multiplexer and combining unit [3]
The specified device allows you to convert analog signals of subscribers to digital signals, however, the conversion of linear signals is not provided, because in the signals of subscriber lines, these signals are absent.

 The technical result achieved is the possibility of converting telephone signals with the simultaneous coupling of analog and digital alarm systems (linear signal exchange methods), and alarm systems can be different (for example, analog single or dual frequency, with different nominal signal frequencies).

 The drawing shows a structural functional diagram of a device for analog-to-digital and digital-to-analog conversion of telephone signals.

A device for analog-to-digital and digital-to-analog conversion of telephone signals contains n blocks of pairing and coding 1 ₁ -1 _n , k each of which is connected to four-wire analog lines, a group receiver of linear signals 2, a transcoding unit 3, a digital line 4, an allocation unit, and input service channels 5, the control unit 6 and the generator unit 7.

Device analog-to-digital and digital-to-analog conversion of telephone signals works as follows. The n interface and coding blocks 1 ₁ -1 _n (each with k four-wire analog lines each) receive telephone signals from an analog telephone exchange, and the telephone signals include signaling signals (linear signals), for example, at frequencies of 1200, 1600 and 2600 Hz , depending on the alarm system on the analog side. The number of channels of the digital system is [(n • k) + p] where p is the number of service digital channels allocated for digital linear signals. If you directly convert analog signals to digital form using known ADCs, the digital telephone exchange does not perceive them, since it does not receive linear signals, which means that it does not have information about the number of the called party, etc.

 Consider the operation of the device on the example of a digital line with a compacted system PCM-30. For channel information and linear signals in the PCM-30 digital stream, two channel intervals of zero and sixteenth are allocated, for the transmission of telephone signals thirty channel intervals.

In this case, there are ten tracking and coding blocks 1 ₁ -1 ₁₀ , each of which is connected to three four-wire analog connecting lines (long-distance channel). After galvanic isolation, in the interface and coding units 1 ₁ -1 _10, the analog signals are transmitted to encoders that perform digital-time conversion of signals, and through the multiplexer interrogating the encoders, they are combined on a time basis with digital signals from other interface and coding units 1 ₁ -1 ₁₀ . After combining, the digital stream is a time sequence of digital signals with a channel structure. The group receiver of linear signals 2 analyzes each channel interval of the stream and detects sequences of code combinations corresponding to the presence of linear signals in the analog trunk lines. This information is supplied to the control unit 6, which can be used as a microprocessor. When a linear signal is detected in the analog trunk line, the auxiliary channel extraction and input unit 5 generates a corresponding linear signal in the channel interval 16 of the stream.

 In transcoding unit 3, the digital stream is converted into a standard HDB-3 signal corresponding to conventional transmission systems, and enters digital line 4.

The HDB-3 signal received from digital line 4 is converted by the transcoding unit 3 into a serial digital stream, supplied to the interface and coding units 1 ₁ ^o C1 _n , where it is demultiplexed and fed to the decoders. Signals converted by decoders into analog form, through galvanic isolation enters the analog connecting lines.

 Channel interval 16 of the serial digital stream is analyzed by the auxiliary channel allocation and input unit 5. If there is a digital linear signal in a certain service channel, the auxiliary channel allocation and input unit 5 transmits information about this to the control unit 6. At the command of the control unit 6, the generator unit 7 generates a sequence code combinations corresponding to the analog linear signal, and transmits it in the desired channel interval of the digital stream. This sequence is converted by the decoder into analog form and enters the analog trunk as a linear signal.

 In the generator unit 7, signals corresponding to all time intervals of the device (essentially synchronization signals) are generated, and binding to the signals of digital line 4 is carried out.

 It should be noted that the control unit 6 also receives information about the operation of the device units with which it is associated and has the ability to transmit it for monitoring and diagnostics.

 A device for analog-to-digital and digital-to-analog conversion of telephone signals is installed between analogue and digital telephone exchanges on the city, intrazonal and long-distance telephone networks, ensuring their joint functioning.

Claims (1)

 A device for analog-to-digital and digital-to-analog conversion of telephone signals, comprising n interface and coding units, the signal inputs of which are connected to the output of the generator unit, as well as a conversion unit connected to the generator unit, and a control unit, the output of which is connected to the control inputs of the interface and coding units characterized in that a group receiver of linear signals and a block for extracting and inputting service channels are introduced, the information input of which is connected to the output of the transcoding unit and information inputs of the interface and coding units, the information digital outputs of which are combined and connected to the information input of the group receiver of linear signals, the information output of the allocation and input unit of service channels and the input of the transcoding unit, while the output of the generator block is connected to the clock input of the group receiver of linear signals, information the output of which is connected to the input of the control unit, which is connected to the block allocation and input service channels, and the control output of the block control is connected to the input of the generator unit.