Non-retriggerable one-shot circuit

A non-retriggerable one-shot circuit for extracting information representative of a clock having a period T from a sequence of input pulses such that the interval between two consecutive input pulses is either T or T/2, said circuit having an input terminal for receiving said input pulses and comprising:

• a frequency detector connected to said input terminal for developing a reference voltage dependent on T, the frequency detector comprising a first ramp generator for generating a voltage that increases monotonically with passage of time after occurrence of an input pulse in said sequence, and a hold circuit for holding the peak voltage of the ramp,
• an interval measurement circuit,
• a comparator for comparing the voltage developed by the interval measurement circuit with the reference voltage and providing an output pulse when a predetermined relationship exists therebetween, and
• enabling means connected between the input terminal and the interval measurement circuit and responsive to said output pulse for allowing an input pulse received at the input terminal to be communicated to the interval measurement circuit,
• said interval measurement circuit developing a voltage dependent on the time that has elapsed since receiving the input pulse communicated from said enabling means and comprising a second ramp generator for generating a voltage that increases monotonically with the passage of time after receiving the input pulse communicated from said enabling means.

A circuit for extracting information representative of a clock having a period T from a sequence of input transitions such that the interval between two consecutive input transitions is either T or T/2, said circuit comprising:

• a differentiator connected to receive the sequence of input transitions and providing a sliver pulse in response to each input transition,
• a retriggerable frequency detector for receiving the sliver pulses and developing a reference voltage dependent on T,
• an interval measurement circuit connected to receive sliver pulses for developing a voltage dependent on the time that has elapsed since receiving a sliver pulse,
• a comparator for comparing the voltage developed by the interval measurement circuit with the reference voltage and providing an output pulse when a predetermined relationship exists therebetween, and
• enabling means connected between the differentiator and the interval measurement circuit and responsive to said output pulse for allowing a sliver pulse provided by the differentiator to be communicated to the interval measurement circuit.

A non-retriggerable one-shot circuit for extracting information representative of a clock having a period T from a sequence of input pulses such that the interval between two consecutive input pulses is either T or T/2, said circuit having an input terminal for receiving said input pulses and comprising:

• a frequency detector connected to said input terminal for developing a reference voltage dependent on T, said frequency detector comprising a first ramp generator for generating a voltage ramp of which the amplitude depends on the time that has elapsed since occurrence of an input pulse in said sequence,
• a comparator means for comparing the voltage developed by the interval measurement circuit with the reference voltage and providing an output pulse when a predetermined relationship exists therebetween, and
• enabling means connected between the input terminal and the interval measurement circuit and responsive to said output pulse for allowing a pulse received at the input terminal to be communicated to the interval measurement circuit,
• said interval measurement circuit developing a voltage dependent on the time that has elapsed since receiving the input pulse communicated from said enabling means and comprising a second ramp generator, substantially identical to the first ramp generator, for generating a voltage dependent on the time that has elapsed since receiving the input pulse communicated from said enabling means.