Code of Federal Regulations (alpha)

CFR /  Title 47  /  Part 24  /  Sec. 24.135 Frequency stability.

(a) The frequency stability of the transmitter shall be maintained within 0.0001 percent (1 ppm) of the center frequency over a temperature variation of -30 [deg]Celsius to + 50 [deg]Celsius at normal supply voltage, and over a variation in the primary supply voltage of 85 percent to 115 percent of the rated supply voltage at a temperature of 20 [deg]Celsius.

(b) For battery operated equipment, the equipment tests shall be performed using a new battery without any further requirement to vary supply voltage.

(c) It is acceptable for a transmitter to meet this frequency stability requirement over a narrower temperature range provided the transmitter ceases to function before it exceeds these frequency stability limits.