KR960003145A - Echo cancellation circuit in mobile telecommunication switching network - Google Patents

Abstract

In the present invention, in the implementation of a circuit for raising echo generated when the PLMN and the public switched telephone network (PSTN) are interlocked, an echo cancellation circuit can be configured in a simple and economical manner by eliminating complexity. In accordance with the present disclosure, a plurality of high-level latches may be used to output a signal for enabling a corresponding latch as necessary, and to perform echo cancellation with the one-chip controller 210. Decoder and latch circuit 220 for latching data halfway between DSPs 321 to 32n, EPROM 310 for storing DSP programs, PCM voice data and echo canceled PCM data for DSP to echo cancellation. PCM sub-highway matching circuit 400 for transmitting and receiving with the switch device. As a result, since each of the plurality of DSPs 321 to 32n downloads the DSP program into its own internal memory with one EPROM 310, there is no need to allocate each DSP program R0M or data RAM. The chip controller 210 and the decoder and latch circuit 220 perform arbitration of the address bus and data bus which are commonly connected between the EPROM 310 and the plurality of DSPs 321 to 328. It can also prevent data collisions.

Description

Echo cancellation circuit in mobile telecommunication switching network

As this is a public information case, the full text was not included.

1 is a block diagram schematically showing the configuration of an echo cancellation circuit according to the present invention;

2 is a block diagram showing the detailed configuration of the DSP circuit 320 of FIG.

Claims (3)

A circuit for eliminating echoes generated during interworking between a digital mobile telecommunication switching network (PLMN) and a public telecommunication network (PSTN); A control bus matching circuit 100 for exchanging information with a control processor for controlling transmission and reception of PCM voice data signals; When the voice transmission from the mobile subscriber of the PLMN is made through the control bus matching circuit 100, a control function for removing echoes generated in the 2-wire / 4-wire hybrid of the public telephone network by executing a predetermined program. A control unit 200 performing the operation; The memory 310 storing the digital signal processing program and the digital signal processing program after downloading the digital signal processing program from the memory 310 in response to an instruction of the controller 200, and then executing the digital signal processing program to perform the digital telephone processing network. A DSP unit (300) comprising DSP circuitry (320) for canceling echoes by performing filtering on mixed PCM speech data signals from the 2-wire and 4-wire hybrids of the? A PCM subhighway matching circuit 400 connected between the time switch device and the DSP circuit 320 for transmitting and receiving the echo canceled PCM voice data signal and the PCM voice data signal to be echo canceled therebetween. Echo cancellation circuit of a mobile communication switching network. The method of claim 1; The DSP circuit 320 includes a plurality of digital signal processors (DSPs) 321 to 32n respectively connected between the controller 200 and the PCM subhighway matching circuit 400; The controller 200 is connected to the controller 210 performing all control functions related to echo cancellation, the plurality of DSPs, and in response to an address of the controller 210 being input, the plurality of DSPs. In addition to selecting one, the control data provided from the controller 210 is latched and transferred to the selected one DSP or the data provided from the selected one DSP is latched to control the plurality of DSPs. A mobile communication switching network comprising a decoder and a latch circuit 220 for transmitting to the controller 210 and an interrupt encoder 230 for transmitting interrupts respectively output from the plurality of DSPs to the controller 210. Echo cancellation circuit in. The method of claim 1 or 2; The PCM subhighway matching circuit 400 includes a counter circuit 410 for generating a predetermined clock in response to a clock CLK and a synchronization pulse FS provided from the time switch device; A decoder circuit 420 for providing a synchronous clock to each of the plurality of DSPs 321 to 32n in response to a clock provided from the counter circuit 410; In response to the predetermined clock provided from the counter circuit 410, when the plurality of DSPs 321 to 32n transfer the echo canceled PCM voice data signal to the time switch device, the plurality of DSPs 321 to 32 n. The plurality of signals may be transmitted by using the signal received from the counter circuit 410 to prevent data conflicts that may occur when 32n) simultaneously transmits data to the serial transmission port, and to prevent data transmission of another DSP due to an errored DSP. A selection circuit 430 for opening the serial transmission path of the corresponding DSP among the DSPs 321 to 32n of the DSP while closing the serial transmission path of the other DSP; A buffer 440 for receiving a signal (DR) mixed with a reference input signal (DI) required for echo cancellation received from the time switch device and a return signal through a two-wire / four-wire hybrid of a fixed subscriber and transmitting it to each DSP. Echo cancellation circuit in a mobile communication switching network comprising a). ※ Note: The disclosure is based on the initial application.