A frequency synthesizer is designed and implemented by using a phase - locked loop in the band from 435 MHz to 440 MHz with 12.5 KHz steps. Off the shelf items such as a crystal oscillator (10.000000MHz), a phase detector ,a programmable frequency divider, and a dual - modulus prescaler are used for the loop. The voltage controlled oscillator (VCO) using a dieletric resonator of high Q is designed and fabricated which yields output power of 10 dBm with a flat frequency response over 10 MHz band with a slope of 2.15 MHz/V. The frequency stability of the synthesizer is measured less than 100 Hz (0.25 ppm) and the power of harmonic components less than 30 dB of the fundamental frequency signal.
