The application of precision frequency control has played an important role in establishing SSB as a reliable means of radio communications. The crystal oscillator thus provides one of the vital links required for the implementation of SSB. As will be seen subsequently, the crystal oscillators used for SSB are often required to maintain a higher degree of accuracy than those used in many other applications. The material covered in this chapter deals primarily with crystal oscillators in the frequency stability range required for SSB equipment operating at HF or VHF bands. The design of higher-precision frequency standards that might be used for microwave SSB links is beyond the scope of this book, and the reader is referred to the references at the end of this chapter. Thus, both temperature-compensated crystal oscillators and crystal ovens of the type used to achieve a frequency stability in the ppm range are addressed. Since the quartz crystal itself plays such a vital role in determining the oscillator performance, a section is included discussing many of the characteristics of the crystal itself. A brief sketch is also included presenting a historical review of frequency control in SSB equipment.

Chapter Contents:

• 11.1 Historical Notes on Frequency Stability
• 11.2 Crystal Oscillator Design
• 11.3 Temperature Control
• 11.4 Temperature Compensation
• References

Inspec keywords: frequency standards; frequency stability; frequency control; crystal oscillators; microwave links

Other keywords: temperature-compensated quartz crystal oscillator; frequency stability; frequency standard; microwave SSB link equipment; radio communication; frequency control; crystal oven

Subjects: Measurement standards and calibration; Piezoelectric devices; Oscillators; Frequency measurement; Frequency control