Electronic Design

Prescalar Circuit Extends Trigger Range Of Scopes And Counters To 16 GHz

Developed by Picosecond Pulse Labs of Boulder, Colo., the 5650 Trigger Countdown prescalar circuit extends the triggering-frequency range of high-speed oscilloscopes and frequency counters to 16 GHz. Most of these instruments can only accommodate 2-GHz and smaller signals.

The 5650 automatically finds the operating point, saving the user a lot of time. It also eliminates the painstaking and annoying tasks that normally are required when designers use manual-intervention methods common to many tunnel-diode prescalar devices. In fact, it doesn't need any adjustments to achieve synchronization.

This divide-by-8 unit extends the trigger range by dividing a 16-GHz signal down to 2 GHz for each of the target instrument's trigger inputs. It's compatible with many oscilloscopes and frequency counters, including those by Agilent Technologies and Tektronix.

Key specifications include a typical range of 200 MHz to 16 GHz, with a guaranteed range of 0.5 to 15 GHz. Typical sensitivity reaches −17 dBm at 1 GHz and −2 dBm at 16 GHz. Maximum continuous-wave input power is 10 dBm over the 0.5- to 12-GHz range and 4 dBm over the 12- to 16-GHz range.

Jitter is specified at less than 1 ps rms, typical. That's extremely low for a device with such a wide dynamic frequency range. The unit features a 50-Ω input/output impedance. It measures 1.25 by 1.75 by 0.625 in., not including the connector. Furthermore, on Agilent oscilloscopes, the 5650 utilizes the instrument's own power source by plugging into the scope's power connector.

The 5650 Power Countdown unit costs $950 each in small quantities. Availability is from stock to four weeks.

Picosecond Pulse Labs, P.O. Box 44, Boulder, CO 80306; (303) 443-1249; fax (303) 447-2236; www.picosecond.com.

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