Constant gain bandwidth product communication satellite repeater

Claim 2

A circuit for optimizing transmission of an input signal wherein said input signal has a frequency bandwidth which is variable over a predetermined range of frequencies, said circuit comprising: a plurality of signal transmission channels arranged to receive said input signal in parallel, each channel including a filter and a variable-gain amplifier connected in circuit and providing a channel output signal, said filter having a bandwidth differing from the bandwidths of the filters in each of the other channels and encompassing a preselected portion of said range of frequencies, said amplifier having a nominal gain differing from the nominal gains of the amplifiers in each of the other channels, wherein the product of the filter bandwidth amplifier gain same in each channel, each channel additionally including means for deriving a detected signal having an amplitude which is a function of the amplitude of said channel output signal; means for mutually comparing said detected signals and providing a control signal having an amplitude at least equal to the highest detected signal amplitude; and control means for each channel for reducing the gain of the amplifier in that channel as a function of the amplitude difference between said control signal and the detected signal from that channel.

Claim 3

The circuit according to claim 1 further comprising means for combining the output signals from all of said channels to provide an output signal for said circuit.

Claim 4

The circuit according to claim 1 wherein said means for mutually comparing comprises means for summing the amplitudes of all of said detected signals, and wherein said control means for each channel includes a subtractor circuit for providing a gain control signal having an amplitude proportional to the difference between the sum of the amplitudes of all of said detected signals and the amplitude of the detected signal from that channel, said control means further including means for applying said gain control signal to the amplifier of that channel to control the gain thereof such that the larger the gain control signal amplitude the greater the reduction of amplifier gain.

Claim 5

The circuit according to claim 1 wherein said means for mutually comparing comprises a peak detector circuit for providing a further signal with an amplitude equal to the highest-amplitude detected signal, and wherein said control means for each channel includes a subtractor circuit for providing a gain control signal having an amplitude proportional to the difference between the amplitude of said further signal and the amplitude of the detected signal from that channel, said control means further including means for applying said gain control signal to the amplifier of that channel for controlling the gain thereof such that the greater the gain control signal amplitude the greater the reduction of amplifier gain.

Claim 6

A circuit for optimizing transmission of an input signal wherein said input signal has a frequency bandwidth which is variable over a predetermined range of frequencies said circuit comprising: a plurality of signal transmission channels arranged to receive said input signal in parallel, each channel including a filter for receiving and filtering said input signal and an amplifier for receiving said input signal after filtering and providing an amplified output signal, said channels being arranged in a sequence wherein the bandwidths of said filters increase in geometric progression and are centered about a common frequency in said predetermined range of frequencies, the gains of said amplifiers being such that the product of filter bandwidth and amplifier gain is the same for each channel, and rectifier-filter means for providing a dc signal at an amplitude representative of the amplitude of said amplified output signal; a first plurality of subtractor means, each for comparing a respective pair of said dc signals from resPective adjacent channels in said sequence and providing a difference signal having an amplitude representative of the amplitude difference between said pair of dc signals, said difference signals being arranged in a further sequence wherein each succeeding difference signal is derived from an adjacent channel pair in which the filter bandwidths are of increasing size; a second plurality of subtractor means, each for comparing a respective pair of said successive difference signals in said further sequence and providing a gating signal only when the amplitudes of said pair of successive difference signals are substantially different; and a plurality of transmission gates, each responsive to a respective gating signal applied thereto for transmitting a corresponding one of said amplified output signals.

Claim 7

A circuit for optimizing transmission of an input signal wherein said input signal has a frequency bandwidth which is variable over a predetermined range of frequencies said circuit comprising: a plurality of signal transmission channels arranged to receive said input signal in parallel, each channel including a filter for receiving and filtering said input signal and an amplifier for receiving said input signal after filtering and providing an amplified output signal, said channels being arranged in a sequence wherein the bandwidths of said filters increase in geometric progression and are centered about a common frequency in said predetermined range of frequencies, the gains of said amplifiers being such that the product of filter bandwidth and amplifier gain is the same for each channel, and rectifier-filter means for providing a dc signal at an amplitude representative of the amplitude of said amplified output signal; a first plurality of subtractor means, each for comparing a respective pair of said dc signals from resPective adjacent channels in said sequence and providing a difference signal having an amplitude representative of the amplitude difference between said pair of dc signals, said difference signals being arranged in a further sequence wherein each succeeding difference signal is derived from an adjacent channel pair in which the filter bandwidths are of increasing size; a second plurality of subtractor means, each for comparing a respective pair of said successive difference signals in said further sequence and providing a gating signal only when the amplitudes of said pair of successive difference signals are substantially different; and a plurality of transmission gates, each responsive to a respective gating signal applied thereto for transmitting a corresponding one of said amplified output signals.

Claim 8

A signal transponder capable of automatically narrowing its own frequency bandwidth in accordance with the bandwidth of a received input signal, said transponder comprising: n signal transmission channels arranged to receive said input signal in parallel, said channels each including a filter for receiving and filtering said input signal, an amplifier for receiving and amplifying the filtered input signal to provide a channel output, and detector means for providing a detected signal having an amplitude representative of the amplitude of said channel output signal, said channels being arranged in a sequence wherein the frequency bandwidths of said filters form a geometric progression and are centered about a common frequency within the bandwidth of said input signal, the gains of said amplifiers being adjusted such that the product of filter bandwidth and amplifier gain is the same for each channel; n- 1 subtractor means, each responsive to application of a respective pair of said detected signals thereto for providing a difference signal having an amplitude representative of the amplitude difference between said pair of detected signals, said n- 1 subtractor means being arranged such the jth subtractor means receives its pair of detected signals from the jth and (j+ 1)st channel; n- 2 further subtractor means, each responsive to application of a respective pair of said difference signals thereto for providing a gating signal only when there is a difference in amplitude between said difference signals, said further subtractor means being arranged such that the jth further subtractor means receives its pair of difference signals from the jth and (j+ 1)st of said n- 1 subtractor means; and n- 2 transmission gates, each responsive to a respective one of said gating signals applied thereto for transmitting a respective one of said channel output signals, said transmission gates being arranged such that the jth transmission gate has applied thereto the gating signal from the jth further subtractor means and the channel output signal from the (j+ 2)nd channel.

Claim 9

A signal transponder capable of automatically narrowing its own frequency bandwidth in accordance with the bandwidth of a received input signal, said transponder comprising: n signal transmission channels arranged to receive said input signal in parallel, said channels each including a filter for receiving and filtering said input signal, an amplifier for receiving and amplifying the filtered input signal to provide a channel output, and detector means for providing a detected signal having an amplitude representative of the amplitude of said channel output signal, said channels being arranged in a sequence wherein the frequency bandwidths of said filters form a geometric progression and are centered about a common frequency within the bandwidth of said input signal, the gains of said amplifiers being adjusted such that the product of filter bandwidth and amplifier gain is the same for each channel; n- 1 subtractor means, each responsive to application of a respective pair of said detected signals thereto for providing a difference signal having an amplitude representative of the amplitude difference between said pair of detected signals, said n- 1 subtractor means being arranged such the jth subtractor means receives its pair of detected signals from the jth and (j+ 1)st channel; n- 2 further subtractor means, each responsive to application of a respective pair of said difference signals thereto for providing a gating signal only when there is a difference in amplitude between said difference signals, said further subtractor means being arranged such that the jth further subtractor means receives its pair of difference signals from the jth and (j+ 1)st of said n- 1 subtractor means; and n- 2 transmission gates, each responsive to a respective one of said gating signals applied thereto for transmitting a respective one of said channel output signals, said transmission gates being arranged such that the jth transmission gate has applied thereto the gating signal from the jth further subtractor means and the channel output signal from the (j+ 2)nd channel.

Claim 10

A circuit for optimizing transmission of an input signal wherein said input signal has a frequency bandwidth which is subject to change over a predetermined frequency range, said circuit comprising: a plurality of signal transmission channels arranged to receive said input signal in parallel, each channel including a filter of preselected bandwidth differing from the bandwidths of the filters in each of the other channels and encompassing a portion of said predetermined frequency range; control means for controlling passage of said input signal through each channel in accordance with the amplitude of the output signal provided by that channel; and wherein said channels are arranged in a sequence in which the bandwidths of said filters are related in accordance with a predetermined geometric progression and are centered about a common frequency; said control means comprising a plurality of transmission gates, one each connected to receIve the output signal from a respective one of said channels, means for monitoring the difference in amplitude between output signals of adjacent pairs of channels in said sequence, and means for inhibiting all but that transmission gate receiving the output signal from the channel having the smallest bandwidth and an output signal which differs in amplitude from the output signals in both adjacent channels in said sequence.

Claim 11

A circuit for optimizing transmission of an input signal wherein said input signal has a frequency bandwidth which is subject to change over a predetermined frequency range, said circuit comprising: a plurality of signal transmission channels arranged to receive said input signal in parallel, each channel including a filter of preselected bandwidth differing from the bandwidths of the filters in each of the other channels and encompassing a portion of said predetermined frequency range; control means for controlling passage of said input signal through each channel in accordance with the amplitude of the output signal provided by that channel; and wherein said channels are arranged in a sequence in which the bandwidths of said filters are related in accordance with a predetermined geometric progression and are centered about a common frequency; said control means comprising a plurality of transmission gates, one each connected to receIve the output signal from a respective one of said channels, means for monitoring the difference in amplitude between output signals of adjacent pairs of channels in said sequence, and means for inhibiting all but that transmission gate receiving the output signal from the channel having the smallest bandwidth and an output signal which differs in amplitude from the output signals in both adjacent channels in said sequence.

Claim 12

A repeater for selectively passing signal in accordance with the signal bandwidth, comprising: a plurality of signal transmission channels; means for applying said signal in parallel to each of said channels; each channel including a filter of preselected bandwidth differing from the bandwidths of the filters in each of the other channels, and an amplifier for amplifying the output signal of the filter in the respective channel, the gain of said amplifier being such that the product of amplifier gain and filter bandwidth is the same for each channel; means for deriving from the output signals of the amplifiers dc voltages which have respective magnitudes proportional to the amplitudes of the respective amplifier output signal, and thereby, to the relative correspondence between respective filter bandwidths and the bandwidth of said signal; means for combining the derived dc voltages in preselected combinations to develop control voltages; and means for applying said control voltages to respective channels to inhibit the passage of said signal therethrough in accordance with the amplitude of said control voltages.

Claim 13

A repeater for selectively passing signal in accordance with the signal bandwidth, comprising: a plurality of signal transmission channels; means for applying said signal in parallel to each of said channels; each channel including a filter of preselected bandwidth differing from the bandwidths of the filters in each of the other channels, and an amplifier for amplifying the output signal of the filter in the respective channel, the gain of said amplifier being such that the product of amplifier gain and filter bandwidth is the same for each channel; means for deriving from the output signals of the amplifiers dc voltages which have respective magnitudes proportional to the amplitudes of the respective amplifier output signal, and thereby, to the relative correspondence between respective filter bandwidths and the bandwidth of said signal; means for combining the derived dc voltages in preselected combinations to develop control voltages; and means for applying said control voltages to respective channels to inhibit the passage of said signal therethrough in accordance with the amplitude of said control voltages.

Claim 16

In a system having a plurality of signal transmission channels, each having a filter and an amplifier arranged in sequence, the method of automatically adjusting the transmission bandwidth of said system in accordance with the bandwidth of an input signal applied to the system, said method comprising the steps of: adjusting the bandwidths of said filters in geometric progression about a common frequency; adjusting the gains of said amplifiers such that the product of amplifier gain and filter bandwidth is the same for each channel; applying said input signal in parallel to each of said channels; comparing the output signals from all of said channels to determine the channel of narrowest bandwidth which provides an output signal differing in amplitude from all channels of narrower bandwidths; and inhibiting signal transmission from all but the channel so determined.

Claim 17

In a system having a plurality of signal transmission channels, each having a filter and an amplifier arranged in sequence, the method of automatically adjusting the transmission bandwidth of said system in accordance with the bandwidth of an input signal applied to the system, said method comprising the steps of: adjusting the bandwidths of said filters in geometric progression about a common frequency; adjusting the gains of said amplifiers such that the product of amplifier gain and filter bandwidth is the same for each channel; applying said input signal in parallel to each of said channels; comparing the output signals from all of said channels to determine the channel of narrowest bandwidth which provides an output signal differing in amplitude from all channels of narrower bandwidths; and inhibiting signal transmission from all but the channel so determined.