A frequency synthesizer is an electronic device that produce frequencies related to a reference frequency.

There are various techniques available for frequency synthesizers. They use phase-locked loops, electronic circuits that consist of a phase or frequency detector, low pass filter; and voltage-controlled oscillator. The selection of synthesizers depend on several factors such as cost, complexity, frequency step size, frequency range, settling time, switching rate, phase noise, and output power.
Additional factors like reference spurs, phase noise and lock time are also important in selecting frequency synthesizers.

Uses

These synthesizers are used in many modern devices like:

• Mobile Telephones
• Radio Receivers
• Radiotelephones
• CB Radios
• Walkie-Talkie
• GPS Systems
• Satellite Systems

Applications

These synthesizers are widely used in many fields. Some of the areas where they find their application are:

• Wireless base stations
• Personal Digital Assistants
• Broadband Wireless Access
• Satellite Communications
• Local Area Networks