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Versatile Circuit

IP.com Disclosure Number: IPCOM000094115D
Original Publication Date: 1966-May-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

West, LP: AUTHOR

Abstract

This circuit, consisting of transformer 11, two resistors 12 and 14, and two tunnel diodes 13 and 15, is adaptable for many applications.

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Versatile Circuit

This circuit, consisting of transformer 11, two resistors 12 and 14, and two tunnel diodes 13 and 15, is adaptable for many applications.

If an oscillating signal 20 is applied to the input, the output 22 consists of pulses at twice the frequency of the input. Pulse width is inversely related to the amplitude of the input wave. If either tunnel diode is reversed, then the input and output is reversed. The phase splitting function can be performed by a active circuit rather than a transformer.

With an AM input, a variable pulse-width output is obtained. Linearity, with amplitude modulation depth of less than 50%, is within approximately 5%. Since the pulse-width modulation is twice the AM frequency, this technique allows, through filtering of the PWM output, demodulation of AM signals which had been modulated by signals with bandwidth approaching the AM center frequency.

An AM signal which is 100% modulated is easily converted at the receiver to one which is modulated 50% or less. The circuit is universally applicable for demodulation or conversion to pulse width modulation. Because of large demodulator bandwidths allowed compared to the AM bandwidth, this technique permits a fast AGC for use with a pilot frequency.

With either a single-frequency sine wave input or may other inputs, the circuit can be used as a frequency doubler with square-wave output. With limited FM signals as input, the circuit produces pulse-frequency-modulation output. Filt...