Pulse train generator
AssigneeInternational Standard Electric Corporation
InventorBjorn Ragnar Solberg
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Abstract
A circuit is disclosed for generating a periodic pulse train having any fixed desired duty cycle from a periodic input signal which may be either analog or digital. The input signal is fed to a transistor amplifier whose bias can be varied. The output of the transistor amplifier is coupled to an amplifying element whose possible voltage swing is limited to provide the desired pulse train. The desired pulse train from the amplifying element is coupled through a low-pass filter prior to comparison with a reference voltage in a differential amplifier. The voltage difference at the output of the differential amplifier adjusts the bias of the transistor amplifier such that the voltage of the low pass filtered desired pulse train is very close to the reference voltage.
Claims16
A system for generating a periodic pulse train with any fixed desired duty cycle from a periodic input signal comprising:
- a first source of said input signal;
- a transistor amplifier coupled to said first source, said transistor amplifier having a bias which can be varied;
- an amplifying element direct current coupled to an output of said transistor amplifier, said amplifying element having a voltage swing limited in a predetermined manner to provide said periodic pulse train;
- a first low pass filter coupled to said amplifying element to low pass filter said periodic pulse train;
- a second source of a reference voltage;
- and
- a comparison amplifier coupled to said first low pass filter, said second source and said transistor amplifier to compare the output voltage of said first low pass filter with said reference voltage to produce a difference voltage for coupling to said transistor amplifier to vary said bias of said transistor amplifier to render the value of the output voltage of said first low pass filter very close to the value of said reference voltage.
Dependencies are inferred from the claim text.