Speed and silence are the trademarks of a high-quality microwave frequency synthesizer, and two of the outstanding attributes of the Series DS frequency synthesizers from Herley Communications Techniques, Inc. (Whippany, NJ). The single-enclosure synthesizers, which can be specified for coverage across any part of 0.005 to 20.48 GHz, feature typical switching speeds of 0.3 to 1 µs for step sizes as small as 1 Hz as typically as fast as 300 ns for step sizes from 250 kHz to 20 MHz. The phase noise is a very respectable—120 dBc/Hz at an offset of 10 kHz from a 10-GHz carrier.

The Series DS frequency synthesizers provide the response times and frequency agility required for a wide range of applications, including antenna testing, in satellite communications systems, for digital microwave radios, and in high-throughput automatic-test-equipment (ATE) systems. The modular design can accommodate almost any combination of frequencies within the total range, with resolution as fine or as coarse as required. Even with steps as fine as 1 Hz, the output frequency can be controlled to a precision of ±1 × 10−10.

Within the frequency range from 5.12 to 10.24 GHz, the Series DS synthesizers can be equipped with frequency step sizes of 1 Hz, 100 Hz, 250 kHz, 2.5 MHz, and 20 MHz. For lower-frequency coverage, the synthesizers can maintain the same step sizes or, as an option, can provide a reduction in step size by a factor of 2N in relation to the output frequency. Standard models include the DS-120 with coverage from 2.56 to 10.24 GHz in 250-kHz steps, the DS-121 with coverage from 2.56 to 10.24 GHz in 1-Hz steps, the DS-161 with coverage from 640 MHz to 10.24 GHz in 1-Hz steps, and the DS-151 with coverage from 5 MHz to 10.24 GHz in 1-Hz steps.

The Series DS synthesizers produce +13 dBm output power. Spurious content is −80 dBc from 320 to 1280 MHz and −60 from 10.2 to 20.4 GHz. The single-sideband (SSB) phase noise is −92 dBc/Hz offset 100 Hz from a 10-GHz carrier, dropping to −120 dBc/Hz offset 100 kHz from the carrier and −128 dBc/Hz offset 1 MHz from the carrier. For a 1-GHz carrier, the phase noise is −111 dBc/Hz offset 100 Hz from the carrier and −147 dBc/Hz offset 1 MHz from the carrier.

Frequency can be programmed remotely via parallel TTL binary-coded-decimal (BCD) control signals. The synthesizers are available with a front-panel touch-screen display. Herley Communications Techniques, Inc., 9 Whippany Rd., Whippany, NJ 07981; (973) 884-2580, FAX: (973) 887-6245, e-mail: alalicata@cti-inc.com, Internet: www.cti-inc.com.