Base station oscillator tuned with received clock signal

摘要

To generate a carrier frequency, a base station needs an oscillator with a long-term stability better than 5x10-8. In the case of crystal oscillators it is therefore necessary to regularly adjust the frequency so as to compensate for frequency drift due to aging. The oscillator (OSC) of a base station (BTS) is automatically tuned with the pulse repetition frequency of the clock (CLK) of a digital communication signal (STM). To prevent variations in the pulse repetition frequency of the clock (CLK) from affecting the stability of the carrier frequency (CAR), the oscillator (OSC) is only tuned during times that a quality indicator contained in the digital communication signal (STM) guarantees a high frequency accuracy of 10-11.