Circuit for data transmission in asynchronous mode with a free reception frequency locked on the transmission frequency

摘要

A circuit for transmitting data in asynchronous transfer mode includes two phase-locked loops associated with a transmission unit and a reception unit, respectively. Each PLL is provided with a voltage-controlled oscillator formed by an astable multivibrator. The reference current fixing the free oscillating frequency of the multivibrator that is associated with the reception unit corresponds to the frequency adjustment current of the multivibrator that is associated with the transmission unit. Each VCO includes a differential amplifier, connected as a voltage-to-current converter, receiving two voltages corresponding to the phase error of the loop with which it is associated, and providing a frequency adjustment current of its astable multivibrator.