Abstract: An oscillator circuit for providing an output clock signal is described. The oscillator circuit comprising a voltage reference, a first current source, first capacitor, first capacitor switch, second current source, second capacitor, second capacitor switch, first comparator, second comparator and flip-flop. The first comparator comprises a first chopper-stabilized comparator switchable between a compare phase and a zeroing phase in dependence on the output clock signal and arranged to operate in the compare phase in a first half-phase of the output clock signal to provide a first comparator output from comparing the first capacitor voltage to the reference voltage and in the zeroing phase in the second half-phase.

Abstract: An oscillator circuit for providing an output clock signal is described. The oscillator circuit comprising a voltage reference, a first current source, first capacitor, first capacitor switch, second current source, second capacitor, second capacitor switch, first comparator, second comparator and flip-flop. The first comparator comprises a first chopper-stabilized comparator switchable between a compare phase and a zeroing phase in dependence on the output clock signal and arranged to operate in the compare phase in a first half-phase of the output clock signal to provide a first comparator output from comparing the first capacitor voltage to the reference voltage and in the zeroing phase in the second half-phase.

Abstract: A signalling circuit for a signal channel of a communication network comprises a communication network terminal connectable to the signal channel and to a voltage supply; an input terminal connectable to receive a transmit signal; a driver device comprising a first driver terminal connected to the communication network terminal, a second driver terminal connected to ground, and a driver control terminal connected to the input terminal; wherein the driver device is arranged to connect the communication network terminal to ground in response to a transition from a low to a high voltage driver control signal state of a driver control signal received at the driver control terminal.

Abstract: A signalling circuit for a signal channel of a communication network comprises a communication network terminal connectable to the signal channel and to a voltage supply; an input terminal connectable to receive a transmit signal; a driver device comprising a first driver terminal connected to the communication network terminal, a second driver terminal connected to ground, and a driver control terminal connected to the input terminal; wherein the driver device is arranged to connect the communication network terminal to ground in response to a transition from a low to a high voltage driver control signal state of a driver control signal received at the driver control terminal.