High-quality test signals are usually associated with signal sources in heavy rack-mount equipment enclosures. But in the case of the benchtop model PHS3000 and handheld model PHS4000 frequency synthesizers from upstart instrument supplier Pronghorn Solutions, these are full-featured microwave frequency synthesizers.

The PHS4000 handheld frequency synthesizer (Fig. 1) includes a large keypad along with a front-panel liquid-crystal-display (LCD) screen to provide status updates. Its performance is impressive, with a frequency range of 150 MHz to 9 GHz, better than 500-s frequency switching speed, and better than +10 dBm output power to 6 GHz. The PHS4000 measures just 3.6 x 5.8 x 1.25 in.

The unit is based on a voltage-controlled-oscillator (VCO) high-frequency source, locked in phase to a stable internal or external frequency reference source. It is equipped with its own reference oscillator, a stable 10-MHz oven-controlled crystal oscillator (OCXO) with 2.5 ppm frequency stability with temperature.The PHS4000 (and PHS3000) can also be operated with a 10-MHz external reference oscillator capable of +10 dBm output power, using an SMA connector to "feed" the frequency synthesizer with signals from the external reference.

The PHS4000 exhibits low phase noise across its frequency range (Fig. 2), with typically -105 dBc/Hz performance offset 10 kHz from a 500-MHz carrier and -80 dBc/Hz offset 10 kHz from an 8-GHz carrier. Nonharmonic spurious content is typically -50 dBc or better at 100 kHz from the carrier while harmonics are typically -30 dBc or better, with levels of -60 dBc at 2 GHz and -40 dBc at 4 GHz.

The handheld frequency synthesizer allows frequency to be set with 100-kHz resolution from the front panel, but provides 1-kHz frequency resolution under Universal Serial Bus (USB) control. The frequency switching speed is better than 500 s under USB control. The synthesizer also provides a frequency sweep function that commands the unit to switch across 100 synthesized frequency steps from start to finish.

The PHS3000 is slightly larger than the PHS4000 frequency synthesizer, at 7.0 x 2.2 x 5.0 in. and about 1.5 lbs, and designed for benchtop use. Both are supplied with adapters for operating under AC power, but both can also run for about 4 hours on (optional) rechargeable battery supply. The power consumption is only about 4 W, or about 500 mA current from a +7.4-VDC battery supply. P&A: $3250 and up (either PHS3000 or PHS4000).

Pronghorn Solutions
P.O. Box 3316
Englewood, CO 80111
(720) 808-9832