Leading-Edge Counters Offer Simplicity and Impressive Performance

Today’s state-of-the-art counters offer improved resolution, accuracy and bandwidth over previous models, yet surprisingly the design and operation basically are the same as they were 10 years ago. But now users are clamoring for an instrument that is easier to operate.

A recent market research report from Fluke concurred, and stated that the counter must be easier to use to help reduce operator errors, especially for occasional users. The study investigated some specific situations concerning the operation of counters. It found out that:

The trigger condition can be difficult to set up or interpret, especially when an unexpected result is obtained. In this situation, an oscilloscope often is used to check the trigger settings and the validity of the counter result.

Counters are perceived as communicating in a primitive way, via a single line of a seven-segment display.

Counters often do only part of the job. For example, they do not offer a voltage measuring capability.

The resolution and accuracy of today’s counters are sufficient.

The study also discovered that you want a counter that provides reliable results. The instrument also should display several parameters simultaneously, such as voltage, and offer a capability to view input signals.

VXI-based systems, like benchtop counters, are combining common test and measurement functions in a single module, said Charles Greenberg, product marketing engineer at Racal Instruments. For example, the Racal 3152 Waveform Generator includes a 4-digit frequency counter. In the near future, counters will be incorporated in other products such as DMMs because they lower the cost, save space and are needed in most automatic test systems.

The continued growth of the telecommunications market is driving the sales of counters into a profitable direction, said Bill Griffith, product manager at Hewlett-Packard. Counters must provide high resolution and accuracy. They must be easy to use with fast measurements and less time required to document tests.

The capability to make measurements quickly and easily is important and should not be impeded by the test-equipment layout, said Mr. Griffith. The most common functions must be easily accessed with one or two push buttons. Some counters such as the HP 53100 Series also offer performance-enhancing software that can display data in a strip chart or histogram format, and can export data to PC-based spreadsheets.

The counter functions needed, however, vary according to the market segment, said Johan ter Haar at Fluke. For example, maintenance personnel require an accuracy of 9 to 10 digits for on-site calibrations of communications networks. Manufacturing looks for many hundreds of readings per second for high throughput. R&D wants sub-nanosecond resolution and time-domain analysis with timers/counters that make thousands of readings per second.

The telecommunications and networking markets continue to push the technological envelope of the counter, said Mr. Greenberg. These businesses use increasingly faster data rates that require high accuracy measuring instruments. A high-stability oscillator with 0.01-ppm accuracy, such as the Option 11 for the Racal 2251A Universal Counter/Timer, offers the frequency accuracy for the precise data-rate measurements needed by the telecom business.

Comparison Chart

To find the right counter for your testing needs, review EE’s comparison chart that accompanies this article. You can quickly locate the appropriate instrument type and compare it to similar units for frequency range and resolution, time-base accuracy and special features.

References

1. Griggs-Anderson Research, “Timemaster Counter Concept Research,” Philips Kista Industrier AB, 1993.

2. Research Solution, “The Market for Timemaster for SMI Applications in France, Germany and the United Kingdom, Phase One: Market Mapping; Phase Two: Concept Testing,” 1994.

June 1997