Data set employing a commutating capacitor, tracking, notch filter

Claim 2

In combination, a signal receiver operable for signals in a predetermined frequency range, a commutating capacitor band-rejection filter connected in an input of said receiver and having a principal band-rejection frequency at the frequency of commutation of capacitor connections in said filter, such filter including an input connection and an output connection, a plurality of capacitors connected with one another in a circuit having a predetermined number, greater than two, of terminals, and means for coupling the terminals of different paired combinations of said terminals between said input connection and said output connection in series in the input of said receiver, and means for coupling to said filter a signal for commutating capacitor connections in said filter in a predetermined frequency range for causing said principal band-rejection frequency to track the frequency of said signal in the lastmentioned range.

Claim 3

In combination, a signal receiver operable for signals in a predetermined frequency range, a commutating capacitor band-rejection filter connected in an input of said receiver and having a principal band-rejection frequency at the frequency of commutation of capacitor connections in said filter, and means for coupling to said filter a signal for commutating capacitor connections in said filter in a predetermined frequency range for causing said principal band-rejection frequency to track the frequency of said signal in the last-mentioned range, said coupling means comprising means for producing data signals modulated so that said signals include at least oNe principal frequency component f0 in said last-mentioned range and which component is at a frequency which is substantially higher than the information bit rate of said data signals, and means for coupling to said filter a signal for commutating capacitor connections therein at said principal frequency component.

Claim 4

In combination, a signal receiver operable for signals in a predetermined frequency range, a commutating capacitor band-rejection filter connected in an input of said receiver and having a principal band-rejection frequency at the frequency of commutation of capacitor connections in said filter, and means for coupling to said filter a signal for commutating capacitor connections in said filter in a predetermined frequency range for causing said principal band-rejection frequency to track the frequency of said signal in the last-mentioned range, said coupling means comprising means for producing data signals modulated so that said signals include at least oNe principal frequency component f0 in said last-mentioned range and which component is at a frequency which is substantially higher than the information bit rate of said data signals, and means for coupling to said filter a signal for commutating capacitor connections therein at said principal frequency component.

Claim 5

The combination in accordance with claim 1 in which said coupling means comprises a circuit for coupling, as said commutating signal, a signal for commutating capacitor connections at a frequency f0 above said receiver signal range.

Claim 6

The combination in accordance with claim 1 in which said coupling means comprises a circuit for coupling, as said commutating signal, a signal for commutating capacitor connections at a frequency f0 below said receiver signal range.

Claim 7

The combination in accordance with claim 1 which further comprises a bidirectional signal coupling connection, means for coupling data signals to said coupling connection, and means for coupling an input of said receiver to receive signals from said coupling connection through said filter.

Claim 8

The combination in accordance with claim 2 in which said data signals comprise a frequency shift keyed signal wave including at least first and second principal signal frequency components in said last-mentioned range for representing said data signals, and said coupling means includes means for applying a predetermined harmonic of each of said first and second components to said filter for commutating capacitor connections therein.

Claim 9

In combination, a signal receiver operable for signals in a predetermined frequency range, a commutatable capacitor band-rejection filter connected in an input of said receiver and having a principal band-rejection frequency at the frequency of commutation of capacitor connections in said filter, and means for coupling to said filter a signal for commutating capacitor connections in said filter in a predetermined frequency range for causing said principal band-rejection frequency to track the frequency of said signal in the last-mentioned range, said filter comprising a plurality of commutatable capacitor units, means for connecting said units in parallel-connected branch paths which are connected in series in the input of said receiver, all of said units having a common principal band-rejection frequency which is below said range for said receiver, and each of said units individually further having harmonic effects in said range of said receiver, and said commutating signal coupling means includes means for driving said units in predetermined different phases.

Claim 10

In combination, a signal receiver operable for signals in a predetermined frequency range, a commutatable capacitor band-rejection filter connected in an input of said receiver and having a principal band-rejection frequency at the frequency of commutation of capacitor connections in said filter, and means for coupling to said filter a signal for commutating capacitor connections in said filter in a predetermined frequency range for causing said principal band-rejection frequency to track the frequency of said signal in the last-mentioned range, said filter comprising a plurality of commutatable capacitor units, means for connecting said units in parallel-connected branch paths which are connected in series in the input of said receiver, all of said units having a common principal band-rejection frequency which is below said range for said receiver, and each of said units individually further having harmonic effects in said range of said receiver, and said commutating signal coupling means includes means for driving said units in predetermined different phases.

Claim 11

In combination, a signal receiver operable for signals in a predetermined frequency range, a commutatable capacitor band-rejection filter connected in an input of said receiver and having a principal band-rejection frequency at the frequency of commutation of capacitor connections in said filter, and means for coupling to said filter a signal for commutating capacitor connections in said filter in a predetermined frequency range for causing said principal band-rejection frequency to track the frequency of said signal in the last-mentioned range, said coupling means comprising means for generating a signal in said last-mentioned range, said signal comprising an on-off-modulated signal wave wherein the signal frequency during an on interval is in said last-mentioned range, and said generating means includes means for applying a predetermined harmonic of said on-interval frequency to said filter as said commutating signal.

Claim 12

In combination, a signal receiver operable for signals in a predetermined frequency range, a commutatable capacitor band-rejection filter connected in an input of said receiver and having a principal band-rejection frequency at the frequency of commutation of capacitor connections in said filter, and means for coupling to said filter a signal for commutating capacitor connections in said filter in a predetermined frequency range for causing said principal band-rejection frequency to track the frequency of said signal in the last-mentioned range, said coupling means comprising means for generating a signal in said last-mentioned range, said signal comprising an on-off-modulated signal wave wherein the signal frequency during an on interval is in said last-mentioned range, and said generating means includes means for applying a predetermined harmonic of said on-interval frequency to said filter as said commutating signal.

Claim 13

The combination in accordance with claim 8 in which said generating means includes means, operative during an off-interval of said generating means signal, for disabling said filter.

Claim 14

The combination in accordance with claim 9 in which said disabling means comprises means for selectably bypassing any commutatable capacitor unit of said filter, means for selectively isolating capacitors of any commutatable capacitor unit of said filter from the remainder of said filter, and means for selectably inhibiting said harmonic applying means.

Claim 15

A data set comprising a transmitter operatable on at least one predetermined frequency produced by a clock source within the transmitter, a receiver operable for receiving signals over a predetermined frequency band which substantially excludes frequencies produced by said transmitter, a commutatable capacitor band-rejection filter connected in an input of said receiver, said filter including an input connection and an output connection, a plurality of capacitors connected with one another in a circuit having a predetermined number, greater than two, of terminals, and means for coupling the terminals of different paired combinations of said terminals between said input connection and said output connection in series in the input of said receiver, and means for driving said filter in response to an output signal from said clock source for causing the rejection band of said filter to track said frequency of said transmitter.

Claim 16

A data set comprising a transmitter operatable on at least one predetermined frequency produced by a clock source within the transmitter, a receiver operable for receiving signals over a predetermined frequency band which substantially excludes frequencies produced by said transmitter, a commutatable capacitor band-rejection filter connected in an input of said receiver, said filter including an input connection and an output connection, a plurality of capacitors connected with one another in a circuit having a predetermined number, greater than two, of terminals, and means for coupling the terminals of different paired combinations of said terminals between said input connection and said output connection in series in the input of said receiver, and means for driving said filter in response to an output signal from said clock source for causing the rejection band of said filter to track said frequency of said transmitter.