With more than seventy years of design and development expertise in frequency control and timing, Valpey Fisher has developed an extensive knowledge base that today is leveraged to bring innovative custom solutions to demanding frequency control applications. The company is intensely focused on bringing to its customers the most innovative, value-added solutions to meet all precision timing needs, from military communications to high precision commercial applications.

The new 100 MHz High Frequency Reference Module provides +20 dBm of RF output power with extremely low phase noise, –90 dBc/Hz at 10 Hz offset from the carrier and –170 dBc/Hz at 100 kHz offset. Its temperature stability is approximately 0.1 ppm over a 50°C range. Its frequency range can be extended in both directions and the supply voltage can be specified from 5 to 15 VDC, while maintaining the same performance.

Design and Construction

The High Frequency Reference Module consists of a motherboard with a single chip power amplifier, a voltage regulator, an output SMA connector and feed-throughs. The frequency reference is obtained from an oven-controlled crystal oscillator (OCXO). The OCXO is part of Valpey Fisher’s new product line to meet the demands for sources at ultra-high frequency (up to 1 GHz), with extremely low phase noise and phase jitter, and offers output choices of CMOS, sine wave and PECL. The oscillator utilizes low cost AT-cut crystals for both the oscillator circuit and a noise-reducing filter. The precision 100 MHz OCXO, in a 20 × 20 mm SMD package, is placed on the motherboard as a separate pre-tested module. The OCXO can also be used as a separate device when the output power level of +13 dBm is sufficient and EMI requirements are not very stringent. The High Frequency Reference Module is encapsulated in a 2" × 2" × 0.75" metal can.

Table 1 shows typical measured results taken on the device, compared with the design goals. Typical phase noise characteristics are shown in Figure 1. Figure 2 shows the frequency stability versus temperature.

Fig. 1 Typical phase noise.

Fig. 2 Temperature stability.

Conclusion

Valpey Fisher has developed a 100 MHz High Frequency Reference Module that provides a high RF output power (20 dBm), extremely low phase noise (–90 dBc/Hz at 10 Hz offset, 170 dBc/Hz noise floor), low EMI radiation and good temperature stability, all at low cost.

Valpey Fisher Corp.,
Hopkinton, MA
(800) 982-5737 or (508) 435-6831,
www.valpeyfisher.com