Engineers and technicians may differ on the effectiveness of a circuit layout, but most will agree that a digital oscilloscope is one of the most useful tools for testing and troubleshooting that circuit. And the 6810 series of digital oscilloscopes from Protek Test & Measurement (Allendale, NJ) represent one of the better combinations of price and performance for this class of instrument, with 250-MSamples/s real-time sampling rate and 8-b vertical resolution.

The 6810 series consist of the models 6810MN and 6810CN (see figure), both dual-channel units differing only in their display screen types—the 6810CN has a 256-color VGA liquid-crystal-display (LCD) screen while the 6810MN has a monochrome 320 × 240-pixel LCD screen. Both feature an analog bandwidth of DC to 100 MHz with better than 3.5-ns risetime. Voltage amplitude sensitivity can be adjusted from 2 mV/div to 5 V/div.

The oscilloscopes perform measurement sweeps at rates of 2 ns/div to 50 s/div in a 1-2-5 sequence. Waveforms are displayed as a function of time with 40-ps standard resolution. The resolution can be improved to 10 ps by using a 100:1 zoom function for a close-up view of a waveform segment. The time scale is displayed with ± 100 PPM accuracy thanks to a stable internal temperature-compensated-crystal-oscillator (TCXO) time base.

In addition to showing voltage amplitude as a function of time, the 6810 series can show the frequency components of a captured signal, thanks to a built-in Fast Fourier Transform (FFT) function. Each 6810 series oscilloscope provides 1024 FFT points for frequency analysis, such as characterizing noise in power supplies. They also furnish four different FFT windows, with trade-offs between amplitude accuracy and frequency resolution: Hanning, Hamming, rectangular, and Blackman windows.

The comprehensive design includes a variety of trigger options, including edge, video, and pulse triggers. The instruments are equipped with a USB port. Optionally, extension modules are furnished for RS-232C and GPIB interfaces. A zoom function from 1:1 to 100:1 permits close-up views of a waveform display. Standard capabilities include enough memory to store 10 waveforms and instrument setups, peak detection capability, digital filters, and waveform recording and playback capability. Each oscilloscope is supplied with a pair of passive probes. P&A: $1177 and up; stock. Protek Test & Measurement, a Division of Cigma Technologies, 40 Boroline Rd., Allendale, NJ 07401; (201) 760-9898, FAX: (201) 760-9888, e-mail: sales@protektest.com, Internet: www.protektest.com.