Developing VoIP DSP Systems
Technology
developed at D2 Technologies, and GlobespanVirata 1999-2002
Debugging DSP code in the lab, August 2000
DSP framework software (C and assembly code)
- Command, status, and
data queues, processes and scheduling, interrupt service routines,
boot-strap loading
- TI 54x peripheral
programming; Data Memory Access (DMA), Multi-channel Buffered Serial Port
(McBSP), Host Port Interface (HPI), Hardware Timer, Clock Generator
- DSP speech coders
(G711, G726, G729, G723), telephony tone generators/detectors, Caller ID
type I/II, High Level Data Control (HDLC), Echo Cancellation, Noise Floor
Estimation, Packet Loss Compensation
- Million Instruction Per
Second (MIPS) analysis and performance evaluation
- Memory analysis and
management; wait state effects, hardware requirements
- Data management;
bandwidth, latency, and buffer requirements
DSP drivers and peripheral programming (C and assembly
code)
- Host Processor
Interface (HPI), Motorola mode parallel communication protocols
- Time Division
Multiplexing (TDM), ISDN Oriented Modular Interface (IOM2), General
Circuit Interface (GCI), and Serial Processor Interface (SPI) serial
communication protocols
- Signal-timing analysis
and verification
Telephony Interfaces and Circuits
- Communication and
control of Audio codecs, Subscriber Line Interface Circuits (SLICs),
Digital Access Arrangements (DAAs), ISDN Framers
- Signal calibration and
performance measurement
- Foreign Exchange Office
(FXO) and Foreign Exchange Station (FXS) telephony electronics and
signaling; LSSGR: Signaling for Analog Interfaces, BELLCORE (GR-506-CORE)
DSP algorithm modules (C and assembly code)
- D2 Technologies Voice
Programming Open (VPO) algorithm standard (Express DSP) C callable
assembly coded modules
- Filter design and fixed
point implementation with quantization, scaling, and block processing
- Stack management and
object-oriented C encapsulation
- Performance evaluation
DSP systems hardware design
- Peripheral connections
(clock generation, Host Port Interface, Serial Port Interface, JTAG,
memory)
- Interface logic, analog
circuits, power specification
DSP hardware testing (C and assembly code)
- Memory verification,
ISR testing, clock measurement, telephony circuit performance evaluation
- Mixed signal scope and
logic analyzer, signal generator, differential measurement probe,
temperature probe
- Designed and built
custom analog interface circuits
DSP evaluation
- Evaluated various DSPs
for performance and integration feasibility in Voice over IP (VoIP)
Internet Access Device (IAD) reference designs
Date last modified: 05/07/02