Computer History MuseumSemiconductor History

1979 - Single Chip Digital Signal Processor Introduced

Bell Labs' single-chip DSP-1 Digital Signal Processor device architecture is optimized for electronic switching systems.

Digital signal processing (DSP) applies mathematical techniques to analyze analog signals from natural and electronic sources in order to separate information from background noise. After conversion to digital form, algorithms such as the Fast Fourier Transform filter and reconstruct the data ready for conversion back to a useable analog signal. DSP capability has been implemented in every generation of technology from vacuum tubes to ICs in audio, communications, image, radar, sonar, and voice recognition systems.

2 x 4 multipliers from Fairchild (9334) and AMD (2505) in 1970 were among the first standard IC products to speed math-intensive signal-processing algorithms. TRW LSI Products used a triple-diffused bipolar process to build more complex functions, such as the 16x16 multiplier (MPY 16), used together with the AMD 2901 bit-slice processor for video and defense applications in the late-1970s. MOS peripheral chips to enable signal processing using general-purpose MPUs included the AMI S2811 (1978) for the Motorola 6800 and Intel's 2920 (1979) that combined programmable digital processing and data conversion (1968 Milestone) circuits.

Single-chip DSPs are essentially MPUs with added complex math capabilities. Bell Labs' one-chip DSP-1, a key component of AT&T's ESS digital switch, appeared in May 1979. NEC's fixed-point µPD7720, introduced in 1980 for voiceband applications, was one of the most commercially successful early DSPs. TI's TMS 320 family of 16-bit programmable DSP devices from 1983 found wide application in consumer products from cell phones to toys. Successive generations of more highly integrated DSPs from TI as well as Analog Devices, Motorola, and others power today's mobile phones, disk drives, and HDTV products.



Contemporary Documents

Koral, W. M. "New LSI products," Computers in Aerospace Conference, Los Angeles, Calif. Addendum. A78-12651 02-59 (New York: American Institute of Aeronautics and Astronautics, Inc., 1977)

Nicholson, Blasco, and Reddy. "The S2811 Signal Processing Peripheral," WESCON Technical Papers, Vol. 22, (1978) pp.1-12.

Hoff, M., Jr., Townsend, M. "An analog input/output microprocessor for signal processing," Solid-State Circuits Conference. Digest of Technical Papers. 1979 IEEE International, Vol. XXII (February 1979) pp. 220-221.

Kawakami, Y., Nishitani, T., Sugimoto, E., et. al. "A single-chip digital signal processor for voiceband applications," Solid-State Circuits Conference. Digest of Technical Papers. 1980 IEEE International, Vol. XXIII, (February 1980) pp. 40- 41.

Boddie, J. Daryanani, G., et. al. "A digital signal processor for telecommunications applications," Solid-State Circuits Conference. Digest of Technical Papers. 1980 IEEE International, Vol. XXIII (February 1980) pp. 44-45.

Oral History transcripts online at the Computer History Museum

Cragon, Harvey (TI), an oral history (2009)

More Oral Histories

Gass, Wanda (TI) ,an oral history conducted in 1998 by Frederik Nebeker, IEEE History Center, New Brunswick, NJ, USA.

More Information

Mick, J. R. Digital Signal Processing Handbook. (Sunnyvale: Advanced Micro Devices, Inc., 1976).

Chapman, R. C. ed. "Digital Signal Processor," Special Edition The Bell System Technical Journal Vol. 60, No. 7, Part 2 (September 1981) pp. 1431-1701

Higgins, R. J. Digital Signal Processing in VLSI. (New York: Prentice Hall, 1990).