Photographer: Phil Nelson
Beginning in the 1980s, a diverse selection of lower frequency analyzers appeared in ads and within instrumentation articles in EE. A September 1982 story by Zehntel discussed signature analysis. Also in that issue, Hewlett-Packard advertised two impedance analyzers that both had numeric readouts.
The “Smaller and Smarter Is Better” article in March 1984 listed several signal analyzers including Tecron’s 30-kHz TEF® System 10 that presented time/energy/frequency results as curves or waterfall plots and was based on three Z80 microprocessors. Also discussed in the article, Data Precision’s DATA 6000 Universal Waveform Analyzer had 14-bit resolution to 100 kHz and cross- and auto-correlation capabilities similar to a modern dynamic signal analyzer.
In the May 1984 issue, HP’s Model 3561A linked the dynamic signal analyzer name to vibration and acoustic analysis up to about 100 kHz. Interestingly, this instrument had a bubble memory option. In 50 years time, will phase-change technology have proven to be more robust than magnetic bubbles?
Protocol analyzers were yet another kind of instrument discussed in the June 1986 article “Communications Test Still Growing.” According to the article, Digitech Industries’ Series 500 Protocol Analyzers “allow the operator to monitor, display, emulate, and analyze either DTE or DCE automatically at 72 kb/s, full duplex.” (Digitech was acquired by LeCroy in 1997.) Panasonic’s VP-3683P Protocol Analyzer featured auto configuration and real-time translation and appeared in the same story.
The portable multifunction PrimeLine™ Logic Analyzer with state, timing, and signature capabilities was included in a July 1986 instrumentation review article. HP’s more advanced Model 1631A also was discussed. This instrument combined a two-channel DSO with 27 channels of state analysis and eight timing channels.
In August 1986, FFT analyzers were featured in a spectrum analyzer review, an indication that the dynamic signal analyzer name was going to take a while to catch on. The story listed Scientific Atlanta’s Model SD 380Z, Zonic’s Model 6088 (Zonic acquired by IOtech in 2001), and Panasonic’s VS-3310P, all with 40-kHz bandwidth. Also included were Solartron’s 1201 Realtime Spectrum Analyzer and Ono Sokki’s CF-200 Single-Channel FFT Analyzer with bandwidths of 30 and 20 kHz, respectively. Several companies claimed a 4-kHz real-time FFT rate.
The October 1986 issue highlighted logic analyzers. This category was represented by products from eight companies: Gould (Biomation had been acquired in 1982), HP, Breeze Test Instruments (acquired by Tektronix in 1986), Computer System Associates, Philips (T&M division bought by Fluke in 1992), Dolch Logic Systems, Arium (merged with American Automation in 1991), and Tektronix.
By August 1988, Bruel & Kjaer Instruments had added the Model 2133 Real-Time Frequency Analyzer for acoustic signals. It featured an 80-dB dynamic range and a selection of 1-, 1/3-, 1/12-, and 1/24-octave bandwidths. The PC-based Rapid Systems Model R350 FFT Analyzer also appeared in the August issue. This instrument sampled as fast as 1 MS/s with 12-bit resolution on two channels and was based on the TI TMS32010 DSP chip.
EE’s May 1989 issue included a description of Rockland Scientific’s System/90 FFT Analyzer that used five TMS320C25 DSPs and was hosted by an 80286 PC with an 80287 math coprocessor.
Analyzers of all types continued to proliferate through the 1990s and 2000s as is confirmed by a review of the editorial topics covered in those decades. In addition, a wide range of application areas such as audio quality, electric power corruption, and serial data protocol troubleshooting was addressed. Although each type of problem was different, modular VXI or PXI test equipment often was used in an FFT-based solution.
Enabling the tremendous advances in test-instrument capabilities during the past few decades have been parallel developments in analog-to-digital conversion, digital signal processing, FPGAs, microprocessors, and software engineering. EE will continue to focus on test applications and their solutions as this exciting confluence of complementary technologies continues.