Modulated carrier frequency sources

Claim 2

In an amplitude modulated carrier frequency source, the combination of: amplitude modulator means having a pair of input terminals and an output terminal for producing an output signal at said output terminal which is obtained by modulating the amplitude of a first carrier frequency signal at one input terminal in accordance with a signal at the other input terminal; a differential amplifier having an output terminal connected to said other input terminal of said amplitude modulator means, and having first and second input terminals; first detector means connected between the output terminal of said amplitude modulator means and said first input terminal of said differential amplifier for stabilizing the modulation level in said amplitude modulator means; and compensating means connected to said second input terminal of said differential amplifier for producing a signal at the output terminal thereof which compensates for non-linearity of said first detector means, and including second detector means for detecting the envelope of a stabilized level, amplitude modulated second carrier frequency.

Claim 3

In a source as claimed in claim 1 and wherein said compensating means also includes a second amplitude modulator, means for applying a relatively large amplitude second carrier frequEncy thereto, and a second differential amplifier adapted and arranged to stabilize the modulation level in said second modulator, said second differential amplifier having one input which is obtained by detecting the output from said second modulator and a second input constituted by the modulating frequency.

Claim 4

A signal generator equipment as claimed in claim 2 which also includes a generator proper adapted to generate a plurality of selectable high frequencies and modulating frequencies the two carrier inputs to the two amplitude modulators are two of the selectable frequencies produced by said generator proper and the modulating frequency is one of the selectable audio frequencies produced thereby.

Claim 5

Apparatus as claimed in claim 3 and wherein output from the first differential amplifier is applied as a stabilizing control signal to the first modulator.

Claim 6

Apparatus as claimed in claim 3 and wherein the output from the first differential amplifier is employed as one input to a synchronous rectifier the second input to which is of modulating frequency and the output from which is employed to vary the amplitude of a modulating frequency input to the first modulator.

Claim 7

Apparatus as claimed in claim 5 and wherein said modulating frequency is applied to said first modulator through an attenuator which is arranged to be varied by output from said synchronous rectifier.

Claim 8

Apparatus as claimed in claim 6 and wherein the modulating frequency input to the synchronous rectifier is a squared wave input.

Claim 9

In an amplitude modulated carrier frequency source, the combination of: amplitude modulator means having a pair of input terminals and an output terminal for producing an output signal at said output terminal which is obtained by modulating the amplitude of a first carrier frequency signal at one input terminal in accordance with a signal at the other input terminal; a differential amplifier having an output terminal connected to said other input terminal of said amplitude modulator means, and having first and second input terminals; first detector means connected between the output terminal of said amplitude modulator means and said first input terminal of said differential amplifier for stabilizing the modulation level in said amplitude modulator means; second amplitude modulator means having a pair of input terminals and an output terminal for producing a signal at its output terminal which is obtained by modulating the amplitude of a second carrier frequency signal at one of its input terminals in accordance with a modulating signal at its other input terminal; and second detector means connected between the output terminal of said second modulator means and the other input terminal of said differential amplifier for compensating non-linearity of said first detector means.

Claim 10

In an amplitude modulated carrier frequency source, the combination of: amplitude modulator means having a pair of input terminals and an output terminal for producing an output signal at said output terminal which is obtained by modulating the amplitude of a first carrier frequency signal at one input terminal in accordance with a signal at the other input terminal; a differential amplifier having an output terminal connected to said other input terminal of said amplitude modulator means, and having first and second input terminals; first detector means connected between the output terminal of said amplitude modulator means and said first input terminal of said differential amplifier for stabilizing the modulation level in said amplitude modulator means; second amplitude modulator means having a pair of input terminals and an output terminal for producing a signal at its output terminal which is obtained by modulating the amplitude of a second carrier frequency signal at one of its input terminals in accordance with a modulating signal at its other input terminal; and second detector means connected between the output terminal of said second modulator means and the other input terminal of said differential amplifier for compensating non-linearity of said first detector means.