Research On Voice Signal Acquisition System Based On Embedded Platform

The test for communication anti-reference ability in Voice communication radio andjamming equipment and the objective evaluation of voice interference effect is the key workof the Range Field. The work of the test method research and the safeguard equipmentdevelopment has been included in the12thfive-year research agenda. And all the tests andtasks mentioned above require voice signal acquisition.Nowadays there are several questions in the voice acquisition device for range field tests.They are low sampling rate and sampling accuracy, short acquisition time and without precisetime reference. Focus on these problems, this paper proposed a kind of voice device onembedded system on per chip (sopc) platform. The device is based on field-programmablegate array (FPGA) and advanced RISC machines (ARM). With the trigger of the timeinformation and pulse per second (PPS) output by global positioning system (GPS) and thelocal high precise real time clock (RTC), the device can realize high sampling rate, highsampling precision synchronous data acquisition of both ends of the voice signal, and then getvoice sampling data stored in the SD card. At the same time, encode voice compression atAdaptive Differential Pulse Code Modulation (ADPCM) form using NiosⅡ soft coreprocessor in FPGA, and send the results to test command hall by Ethernet.This paper first introduces FPGA and ARM and SOPC basic concept, then introduced thedesign of the hardware system and software system, and at the end the performance index ofcontrol system is given through the test. In this paper the research mainly has the followingseveral innovations:1. Solve the uncontrollable problem of sampling startup delay by usingFPAG as the voice codec controller.2. Solve the remote synchronization accuracy problemby utilizing GPS system as acquisition system time reference.3. Design the RTC system andsolve the time synchronization when GPS system failure.4. Design the asynchronoustransmission interface between the FPGA and the ARM, which solve the data high-speedtransmission problems.5. Using the voice compression algorithm based on NiosⅡ, thatrealize the voice signal transmission under the condition of limited network bandwidth.The test verified, the system can realize long-time voice signal acquisition of high sampling rate, high sampling accuracy with time reference, get acquisition data stored in thelarge capacity SD card, encode the voice data and send them to the Ethernet. It has met theindex requirements raised by voice acquisition safeguard equipment of the range field.