Process and arrangement for compensating adjacent-channel interference in a double-sideband amplitude modulation system

Claim 2

In an ensemble comprising a mixture of several double-sideband modulated signals including (a) an upper signal at the upper end of the ensemble, such upper signal having an interference-free upper sideband (b) a lower signal at the lower end of the ensemble, such lower signal having an interference-free lower sideband, and (c) an intermediate signal to be received between the upper and lower ends of the ensemble, and wherein: each modulated signal has a different carrier frequency; each of the sidebands of the intermediate signal is overlapped and being interfered with by a sideband of another signal; and it is desired, in order to receive by single-sideband reception the upper sideband of the intermediate signal, a method to eliminate interference with the upper sideband of the intermediate signal including the step of: applying an anti-interference compensation to the sideband interfering with the upper sideband of the intermediate signal, whereby the upper sideband of the intermediate signal is made substantially interference-free.

Claim 3

The method of claim 1 wherein the applying step includes the steps of: A. changing the upper sideband of the upper signal to an inverted position; B. changing the algebraic sign of the inverted upper sideband of the upper signal to provide the anti-interference compensation; C. combining the anti-interference compensation with a mixture of the upper sideband of the intermediate signal and the sideband interfering with the upper sideband of the intermediate signal, thereby obtaining another interference-free upper sideband; and D. repeating the steps of A, B and C to the extent necessary to make the upper sideband of the intermediate signal substantially interference-free.

Claim 4

The method of claim 2 wherein steps A, B, C and D are carried out sequentially in step-by-step fashion.

Claim 5

The method of claim 2 wherein steps A, B, C and D are carried out substantially simultaneously.

Claim 6

In an ensemble comprising a mixture of several double-sideband modulated signals including (a) an upper signal at the upper end of the ensemble, such upper signal having an interference-free upper sideband (b) a lower signal at the lower end of the ensemble, such lower signal having an interference-free lower sideband, and (c) an intermediate signal to be received between the upper and lower ends of the ensemble, and wherein: each modulated signal has a different carrier frequency; each of the sidebands of the intermediate signal is overlapped and being interfered with by a sideband of another signal; and it is desired, in order to receive by single-sideband reception the lower sideband of the intermediate signal, a method to eliminate interference with the lower sideband of the intermediate signal including the step of: applying an anti-interference compensation to the sideband interfering with the lower sideband of the intermediate signal, whereby the lower sideband of the intermediate signal is made substantially interference-free.

Claim 7

In an ensemble comprising a mixture of several double-sideband modulated signals including (a) an upper signal at the upper end of the ensemble, such upper signal having an interference-free upper sideband (b) a lower signal at the lower end of the ensemble, such lower signal having an interference-free lower sideband, and (c) an intermediate signal to be received between the upper and lower ends of the ensemble, and wherein: each modulated signal has a different carrier frequency; each of the sidebands of the intermediate signal is overlapped and being interfered with by a sideband of another signal; and it is desired, in order to receive by single-sideband reception the lower sideband of the intermediate signal, a method to eliminate interference with the lower sideband of the intermediate signal including the step of: applying an anti-interference compensation to the sideband interfering with the lower sideband of the intermediate signal, whereby the lower sideband of the intermediate signal is made substantially interference-free.

Claim 8

The method of claim 5 wherein the applying step includes the steps of: A. changing the lower sideband of the lower signal to an inverted position; B. changing the algebraic sign of the inverted lower sideband of the lower signal to provide the anti-interference compensation; C. combining the anti-interference compensation with a mixture of the lower sideband of the intermediate signal and the sideband interfering with the lower sideband of the intermediate signal, thereby obtaining another interference-free lower sideband; and D. repeating the steps of A, B and C to the extent necessary to make the lower sideband of the intermediate signal substantially interference-free.

Claim 9

The method of claim 6 wherein steps A, B, C and D are carried out sequentially in step-by-step fashion.

Claim 10

The method of claim 6 wherein steps A, B, C and D are carried out substantially simultaneously.

Claim 11

In an ensemble comprising a mixture of several double-sideband modulated signals including (a) an upper signal at the upper end of the ensemble, such upper signal having an interference-free upper sideband (b) a lower signal at the lower end of the ensemble, such lower signal having an interference-free lower sideband, and (c) an intermediate signal to be received between the upper and lower ends of the ensemble, and wherein: each modulated signal has a different carrier frequency; each of the sidebands of the intermediate signal is overlapped and being interfered with by a sideband of another signal; and it is desired, in order to receive by double-sideband reception both sidebands of the intermediate signal, a method to eliminate interference with both sidebands of the intermediate signal including the steps of: A. changing the upper sideband of the upper signal to an inverted position; B. changing the algebraic sign of the inverted upper sideband of the upper signal to provide an anti-interference compensation; C. combining the anti-interference compensation with a mixture of the upper sideband of the intermediate signal and the sideband interfering with the upper sideband of the intermediate signal, thereby obtaining another interference-free upper sideband; D. repeating the steps of A, B and C to the extent necessary to make the upper sideband of the intermediate signal substantially interference-free; E. changing the lower sideband of the lower signal to an inverted position; F. changing the algebraic sign of the inverted lower sideband of the lower signal to provide a second anti-interference compensation; G. combining the second anti-interference compensation with a mixture of the lower sideband of the intermediate signal and the sideband interfering with the lower sideband of the intermediate signal, thereby obtaining another interference-free lower sideband; and H. repeating the steps of A, B and C to the extent necessary to make the lower sideband of the intermediate signal substantially interference-free; and I. adding the upper and lower sidebands of the intermediate signal.

Claim 12

In an ensemble comprising a mixture of several double-sideband modulated signals including (a) an upper signal at the upper end of the ensemble, such upper signal having an interference-free upper sideband (b) a lower signal at the lower end of the ensemble, such lower signal having an interference-free lower sideband, and (c) an intermediate signal to be received between the upper and lower ends of the ensemble, and wherein: each modulated signal has a different carrier frequency; each of the sidebands of the intermediate signal is overlapped and being interfered with by a sideband of another signal; and it is desired, in order to receive by double-sideband reception both sidebands of the intermediate signal, a method to eliminate interference with both sidebands of the intermediate signal including the steps of: A. changing the upper sideband of the upper signal to an inverted position; B. changing the algebraic sign of the inverted upper sideband of the upper signal to provide an anti-interference compensation; C. combining the anti-interference compensation with a mixture of the upper sideband of the intermediate signal and the sideband interfering with the upper sideband of the intermediate signal, thereby obtaining another interference-free upper sideband; D. repeating the steps of A, B and C to the extent necessary to make the upper sideband of the intermediate signal substantially interference-free; E. changing the lower sideband of the lower signal to an inverted position; F. changing the algebraic sign of the inverted lower sideband of the lower signal to provide a second anti-interference compensation; G. combining the second anti-interference compensation with a mixture of the lower sideband of the intermediate signal and the sideband interfering with the lower sideband of the intermediate signal, thereby obtaining another interference-free lower sideband; and H. repeating the steps of A, B and C to the extent necessary to make the lower sideband of the intermediate signal substantially interference-free; and I. adding the upper and lower sidebands of the intermediate signal.

Claim 13

The method of claim 9 wherein the steps are carried out sequentially in step-by-step fashion.

Claim 14

The method of claim 9 wherein steps A, B, C and D are carried out substantially simultaneously.

Claim 15

A circuit arrangement for carrying out the method of claim 3, i.e., for providing a substantially interference-free upper sideband of a double-sideband oscillation to be evaluated, the arrangement including: first, second, third and fourth mixer/filter sections in series, each mixer/filter section including a mixer preceded by a low-pass filter; and wherein: each mixer has a primary input line and first and second input lines; each mixer of each mixer/filter section has a separate attenuator connected to its first input line; each attenuator has one line of a separate frequency-separating network connected thereto; each mixer has another line of the respective separate frequency-separating network connected to its second input line; each frequency-separating network has a separate squarer connected thereto; each squarer has a separate phase shifter connected thereto; and wherein: the phase shifters feeding the first, second, third and fourth mixer/filter sections are identified as P1, P2, P3 and P4, respectively; the phase shifters P1, P2, P3, P4 have inputted thereto the carriers of double-sideband oscillations G, F, E and D, respectively; the oscillations G, F, E and D are in descending order of frequency and each oscillation G, F, E and D has a carrier frequency greater than the carrier frequency of the double-sideband oscillation to be evaluated; the low-pass filter of the first mixer/filter section has a critical frequency identical to the highest frequency of the upper sideband of the oscillation G; the low-pass filter of the second mixer/filter section has a critical frequency identical to the carrier frequency of the oscillation F; the low-pass filter of the third mixer/filter section has a critical frequency identical to the carrier frequency of the oscillation E; the low-pass filter of the fourth mixer/filter section has a critical frequency identical to the carrier frequency of the oscillation D; the low-pass filter of the first mixer/filter section has inputted thereto an ensemble of double-sideband oscillations, such ensemble including the double-sideband oscillation to be evaluated; each frequency-separating network is configured to filter out the DC component of the squared carrier inputted to that network and direct such component to that attenuator connected to such network; each attenuator is configured to reduce such component by about one-half and direct such reduced component to the first input line of the respective mixer connected thereto; and each frequency-separating network is further configured to direct the squared carrier received from its respective squarer to the second input line of the respective mixer connected to such network; and wherein: the mixer of the fourth mixer/filter section has an output line having available thereon the substantially interference-free upper sideband of the double-sideband oscillation to be evaluated.

Claim 16

The circuit arrangement of claim 12 wherein each mixer of the first, second, third and fourth mixer/filter sections is embodied as a multiplier.

Claim 17

A circuit arrangement for carrying out the method of claim 3, i.e., for providing a substantially interference-free upper sideband of a double-sideband oscillation to be evaluated, the arrangement including: first, second, third and fourth filter/summing sections connected in series, each filter/summing section including a low-pass filter and a summing device connected in series, each summing device having an output line, each filter/summing section also including a junction between the low-pass filter and the summing device; a separate input circuit connected to each filter/summing section, each input circuit including a separate squarer Q1, Q2, Q3 and Q4, respectively, the squarers Q1, Q2, Q3 and Q4 having inputted thereto the carriers of double-sideband oscillations G, F, E and D, respectively; a separate amplitude stabilizer connected to each of the respective squarers, a separate attenuator connected to each of the respective amplitude stabilizers and a separate mixer connected to each of the respective attenuators; each mixer receiving a signal from the junction of its respective filter/summing section, each mixer outputting a signal to the respective summing device; and wherein: the low-pass filter of the first filter/summing section has a critical frequency identical to the highest frequency of the upper sideband of the oscillation G; the low-pass filter of the second filter/summing section has a critical frequency identical to the carrier frequency of the oscillation F; the low-pass filter of the third filter/summing section has a critical frequency identical to the carrier frequency of the oscillation E; the low-pass filter of the fourth filter/summing section has a critical frequency identical to the carrier frequency of the oscillation D; the low-pass filter of the first filter/summing section has inputted thereto an ensemble of double-sideband oscillations, such ensemble including the double-sideband oscillation to be evaluated; and wherein: the output line of the summing device of the fourth filter/summing section has available thereon the substantially interference-free upper sideband of the double-sideband oscillation to be evaluated.

Claim 18

A circuit arrangement for carrying out the method of claim 3, i.e., for providing a substantially interference-free upper sideband of a double-sideband oscillation to be evaluated, the arrangement including: first, second, third and fourth filter/summing sections connected in series, each filter/summing section including a low-pass filter and a summing device connected in series, each summing device having an output line, each filter/summing section also including a junction between the low-pass filter and the summing device; a separate input circuit connected to each filter/summing section, each input circuit including (a) a separate regulator Re1, Re2, Re3 and Re4, respectively, and (b) a separate variable-gain amplifier RV1, RV2, RV3 and RV4, respectively; each amplifier RV1, RV2, RV3 and RV4 is connected to a separate squarer Q1, Q2, Q3 and Q4, respectively, and is also connected to a separate mixer Mi1, Mi2, Mi3 and Mi4, respectively; the squarers Q1, Q2, Q3 and Q4 which have inputted thereto the carriers of double-sideband oscillations G, F, E and D, respectively; and wherein: each regulator Re1, Re2, Re3 and Re4 is connected (a) to the output line of a separate summing device, (b) to the input line of such separate summing device and (c) to a separate amplifier; and wherein: the low-pass filter of the first filter/summing section has a critical frequency identical to the highest frequency of the upper sideband of the oscillation G; the low-pass filter of the second filter/summing section has a critical frequency identical to the carrier frequency of the oscillation F; the low-pass filter of the third filter/summing section has a critical frequency identical to the carrier frequency of the oscillation E; the low-pass filter of the fourth filter/summing section has a critical frequency identical to the carrier frequency of the oscillation D; the low-pass filter of the first filter/summing section has inputted thereto an ensemble of double-sideband oscillations, such ensemble including the double-sideband oscillation to be evaluated; and wherein: the output line of the summing device of the fourth filter/summing section has available thereon the substantially interference-free upper sideband of the double-sideband oscillation to be evaluated.

Claim 19

The circuit arrangement of claim 15 wherein: each of the regulators Re1, Re2, Re3 and Re4 includes two multiplying devices Mu2, Mu1; the multiplying devices Mu2, Mu1 receive signals available, respectively, preceding and following a respective summing device, each such multiplying device demodulating such signals and providing an output signal; each regulator Re1, Re2, Re3 and Re4 also including a third multiplying device Mu3 accepting signals from the multiplying devices Mu2 and Mu1 and multiplying such accepted signals together to produce a multiplied output; a low-pass filter receiving the multiplied output from the device Mu3; and a time function element PI receiving the output of the low-pass filter and providing an actuating value for use in the arrangement.