Naigang Zhang

**** ****** **.

Austin, TX *****

Cell Phone: 214-***-****

E-mail: ab9ds5@r.postjobfree.com

Career Objectives

Seek a DSP embedded software and firmware Engineer position with C, C++,

and DSP assembler experience in digital signal processing and

communication system.

Work Experience

Sr. DSP Engineer, Extron Electronics, Texas (June 2012 - Present)

. Working on a new audio system development by using TI C6657 Multicore

DSP.

. Defined the audio system software architecture.

. Designed and implemented audio encoding and decoding channel classes

with inheritance in C++.

. Integrated G.722.1, G.722, G.711 CODECs into the audio encoding and

decoding channels with multithreading.

. Created audio channel pool to dynamically create or remove the audio

encoding and decoding channel objects from the pool, and dynamically

create or remove encoding and decoding tasks.

. Designed and implemented audio CODEC loopback testing routings for the

audio system development testing.

. Design and implemented audio data transporting between two DSP core

processors by using IPC.

. Working on VoIP jitter buffer and packet loss concealment algorithm

development.

Staff DSP Firmware Engineer, Intersil, Austin, Texas (Oct. 2011 - June

2012)

. Worked on the audio signal flow (FIR and IIR filters, EQ, mixer, basic

reverb, and etc enhancement.

. Established methodology to measure MIPS usage on background and

foreground processing.

. Tested D2Audio system to measure the MIPS usage of ProLogic II, SRS,

DVS, DTS, and AC3 decoders

. Integrated the updated audio decoders and signal follows into D2Audio

system. Involved in code optimizations.

Sr. DSP Firmware Application Engineer, Silicon Laboratories, Austin,

Texas (August 2010 - August 2011)

. Designed and implemented a DSP power save mode for fax modem and data

modem application.

. Generated PWM modulating signal spectrum for different sampling

frequencies by Matlab. Analyzed the spectrum to design a low pass

filter for a modem audio application. Validated the PWM circuit and

the digital audio signal processing.

. Created patches to fix customer issues. Supported customers to debug,

test, and solve modem issues.

. Build the modem loads to verify the loads for modem chips final tape

out. Made a system level fax modem test plan.

Sr. Audio DSP Software Engineer, LifeSize Communications, Austin, Texas

(June 2008 - August 2010)

. Designed and implemented an audio subsystem from scratch on TI C6424

DSP for VoIP MCU audio and video conferencing.

. Audio DSP software architecture, memory (RAM and cache) management,

and multitask schedule.

. Defined and implemented encoding, decoding, mixing and command

handler classes with inheritance in C++.

. Dynamically created and removed audio encoding and decoding channels

and multitask during VoIP calls.

. Integrated G.711, G.728, G.729, G.722, G.722.1 and AAC voice and

audio CODECs into audio channels.

. Designed and implemented audio channel pool, RTP handler and

generator, message handler, PCM recording and playback, IVR

channels, mixer channels, and A/V sync dynamic delay buffer.

. Implemented interrupter service routings to handle RTP, PCM, and

command messages.

. Made audio algorithms, features and performance test plan to test

the MCU audio subsystem in real-time environments.

. Created a GEL file to initialize and boot the DSP processors.

. Built DSP images of the MCU audio subsystem for the product.

Sr. DSP Software Engineer, Aware Inc, Bedford, Massachusetts (June 2007 -

June 2008)

. Designed an AFE gain control algorithm and implemented the algorithm

on Aware VDSL modem. Tested the AFE in VDSL modem calls to measure

the quality and performance.

. Debug and test VDSL Modem handshaking and training processing.

Sr. DSP Software Engineer, Tekelec, Plano, Texas (October 2004 - May

2007)

. Work on voice signal processing as a voice feature design prime for

Tekelec Wireless Media Gateways.

. Integrated line echo cancellation, CODEC (G711, G729, G.723 and

AMR), and Automatic Level Control (ALC), Noise Reduction (NR),

Acoustic Echo Control (AEC) into wireless media gateways.

. Contacted with DSP venders. Responsible for specifying requirements

of line echo cancellation and voice processing features for Tekelec

wireless media gateways. TI C54xx, Octasic OCT6100 and Mindspeed

M82xxx DSP chips are used for the voice signal processing on the

wireless media gateways.

. Tested the DSP processing units, voice features, voice quality and

performance of the media gateways.

. Responded for voice quality analysis, trouble-shooting, and support

system level testing for both internal and external customers and

training test engineers to test voice quality and voice features.

. Involved in feature planning, system level voice quality control and

architecture for the media gateway voice processing sub-system.

Sr. Member of Scientific Staff, Nortel Networks, Richardson, Texas

(August 1998- October 2004)

. Worked on VoIP video and audio conferencing system, IVR server, and

soft client on Linux and Windows.

. Integrate G.711, G.729, G.723, G.722 CODECs and DTMF tone detector

into voice channel modules.

. Designed and Implemented RTP packet handler and RTP packet generator

for the conferencing server and soft client.

. Created multiple threads to handle receiving and transmitting UDP

packets for the conferencing server.

. Designed and implemented a voice and video channel dynamic selection

algorithm as well and audio mixing algorithm for the conferencing

server.

. Modified VAD, AEC, AGC, and jitter buffering algorithms and

integrated the algorithms into the conferencing server.

. Measured and tested voice quality and performance of the voice

signal processing units on conferencing server and soft client.

. Implemented a network IP address and port translation function for

UDP packet processing.

. Integrated DivX video CODEC library into video encoding and decoding

channel modules.

. Designed and implemented the prompt builders (Japanese and Chinese

languages) for IVR server.

. Supported MCI and AT&T customs in verification of Nortel line echo

canceller. Involved in system level voice quality control and test

plan development.

DSP Application Designer, Nortel, Ottawa, Canada (May 1996 - August 1998)

. Worked on Nortel DMS250 SPM line echo canceller development on

DSP563xx.

. Designed a phase-reversal tone detection algorithm (US patent

6,055,310). Modeled and simulated the algorithm with Matlab.

Implemented the algorithm on Nortel DMS 250 SPM line echo canceller.

. Designed and implemented tone disabler state machine (G.165, G.164

and SW56K modes).

. Designed and implemented echo canceller adaptive filter allocation

and de-allocation mechanism.

. Improved an echo path change detection algorithm and implemented the

algorithm on the line echo canceller.

. Developed G.168 automatic network echo cancellation testing sets

using a STA testing tool.

DSP Application Design Engineer, SED Systems Inc., Saskatoon, Canada

(August 1995 - April 1996)

. Worked on V.22/V.32 modem development.

. Involved in the scrambler, descrambler, AGC, echo canceller, and

handshaking design and implementation.

Education

. Master of Electrical Engineering (1995), Concordia University,

Montreal, Canada

. Study and research area: digital signal processing and communication

system

US Patents

. "Phase Reversal Tone Detector Using DSP," Patent # 6,055,310

. "Method, System, and Computer-Readable Medium for Calculating an

Echo Path Delay" Patent # 200********

Skills

. Programming Languages: C and C++ OOP

. DSP programming: TI C665x, TI C64xx, TI C5xxx, Freescale DSP563xx,

and Intel IPP

. Simulation Languages, Tools, and Instruments: Matlab, SimuLink, DSP

emulators, Wireshark, Network Analyzers, Audio Precision, Spectrum

Analyzers, and Oscilloscopes

. Work with Operating Systems and Environments: TI Code Composer v5

and BIOS, Linux, Windows and MSVC

. File Management System: ClearCase, SVN, CVS and Perforce

Nationality: US Citizen

Reference available upon request

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