Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
172 words
A frequency shift modulator, comprising a source of an audio frequency band of tone signals, means for deriving from said audio frequency band of tone signals three corresponding bands of tone signals phase separated from each other by 120*, a three phase oscillator for generating three sub-audio modulation signals separated in phase from each other by 120* , three differential amplifiers, each of said differential amplifiers including first and second differentially connected transistors having respectively first and second differential signal input terminals and a common output terminal, means for ac grounding said second differential input terminals of said three differential amplifiers, means applying each of said corresponding bands of tone signals to a different one of said first input terminals of said three differential amplifiers, means For varying the current flow in each pair of said first and second transistors in response to current flow in a different one of the phases of said three-phase oscillator, and means for summing the signals appearing at said output terminals of said three differential amplifiers.
Claim 2
Dependent Claim
172 words
A frequency shift modulator, comprising a source of an audio frequency band of tone signals, means for deriving from said audio frequency band of tone signals three corresponding bands of tone signals phase separated from each other by 120*, a three phase oscillator for generating three sub-audio modulation signals separated in phase from each other by 120* , three differential amplifiers, each of said differential amplifiers including first and second differentially connected transistors having respectively first and second differential signal input terminals and a common output terminal, means for ac grounding said second differential input terminals of said three differential amplifiers, means applying each of said corresponding bands of tone signals to a different one of said first input terminals of said three differential amplifiers, means For varying the current flow in each pair of said first and second transistors in response to current flow in a different one of the phases of said three-phase oscillator, and means for summing the signals appearing at said output terminals of said three differential amplifiers.
Claim 3
Dependent Claim
79 words
The combination according to claim 1, wherein each phase of said three-phase oscillator includes a transistor having a separate RC phase shift feedback circuit and means connecting said feedback circuits in cascade in a closed loop, whereby said three-phase oscillator oscillates at a frequency such that the total phase shift around said closed loop provided by said RC phase shift feedback circuits is 360* and each of said RC phase shift feedback circuits supports a phase shift of 120*.
Claim 4
Dependent Claim
76 words
The combination according to claim 2, wherein each of said RC phase shift feedback circuits includes a separate control transistor connected collector to emitter as an element of that RC phase shift circuit, each of said control transistors having a base, means connecting each of said control transistors in series with a different one of said differential amplifiers to control current flow jointly in the first and second transistors included in each of said differential amplifiers.
Claim 5
Dependent Claim
35 words
The combination according to claim 3, wherein is provided a source of control voltage selective in value, and means for connecting said control voltage commonly to said bases to vary the frequency of said oscillator.
Claim 6
Dependent Claim
21 words
The combination according to claim 4, wherein is provided means for at will disabling only two phases of said three-phase oscillator.
Claim 7
Dependent Claim
176 words
A frequency shift modulator, comprising a source of an aduio frequency band of tone signals, means for deriving from said audio frequency band of tone signals three identical bands of tone signals, corresponding frequencies of which are phase separated from each other by 120*, a three-phase RC ring oscillator including three transistors arranged for generating three sub-audio modulation signals separated in phase from each other by 120* , three amplifiers each including at least one transistor, each of said amplifiers including a signal input terminal and a signal output terminal, means applying each of said three identical bands of tone signals to a different one of said signal input terminals, means for varying current flow through each of said amplifiers to said output terminals in response to current flow in a different one of said three transistors of said three-phase oscillator, said last means including a series connection of each of said three amplifiers with a different one of said transistors, and means for summing the signals appearing at said output terminals of said three amplifiers.
Claim 8
Dependent Claim
176 words
A frequency shift modulator, comprising a source of an aduio frequency band of tone signals, means for deriving from said audio frequency band of tone signals three identical bands of tone signals, corresponding frequencies of which are phase separated from each other by 120*, a three-phase RC ring oscillator including three transistors arranged for generating three sub-audio modulation signals separated in phase from each other by 120* , three amplifiers each including at least one transistor, each of said amplifiers including a signal input terminal and a signal output terminal, means applying each of said three identical bands of tone signals to a different one of said signal input terminals, means for varying current flow through each of said amplifiers to said output terminals in response to current flow in a different one of said three transistors of said three-phase oscillator, said last means including a series connection of each of said three amplifiers with a different one of said transistors, and means for summing the signals appearing at said output terminals of said three amplifiers.