Question

Calculate the frequency for maximum drift of crystal if The crystal has a stability of 6300 ppm and an output frequency of 268.2MHz and frequency multiplier chain with factors of 2, 3, and 3.

(a) 123.5MHz

(b) 423.2MHz

(c) 269.65MHz

(d) 235.1MHz

I have been asked this question in class test.

I'm obligated to ask this question of Radio Transmitters topic in section Radio Transmitters, Communication Receivers, Multiplexing and Demultiplexing of Avionics

Answer 1

Correct choice is (c) 269.65MHz

The best explanation: Variation = 300ppm = 0.03%

This variation is multiplied by the frequency multiplier chain, yielding

0.03 percent x 18 =60.54 percent. Now, 268.2 MHz x 0.0054 = 1.45 MHz.

Thus, the frequency of the transmitter output is 268.2 + 1.45 MHz. The maximum frequency is

268.2 + 1.45 = 269.65 MHz.