# US 5,703,530 A · Radio frequency amplifier having improved CTB and cross modulation characteristics > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,703,530 A - Document ID: US5703530A - Status: Granted - Kind: A - Application number: 08/623,700 - Filed: 1996-03-29 - Granted: 1997-12-30 - Earliest claimed: 1995-10-06 - Assignees: Yagi Antenna Co., Ltd. - Inventors: Yuzo Sato; Katsumi Kaneko; Yasushi Saito - Web page: https://patentgrep.com/patent/US5703530A ## CPC - H03F 1/32: Modifications of amplifiers to reduce non-linear distortion (by negative feedback H03F1/34) - H03F 3/19: with semiconductor devices only - H03F 3/26: Push-pull amplifiers; Phase-splitters therefor (duplicated single-ended push-pull arrangements or phase-splitters therefor H03F3/30) - H03F: AMPLIFIERS ## Abstract A radio-frequency amplifier circuit of simple construction having low power consumption and low heat generation and which amplifies an input signal while maintaining composite triple beat (CTB) distortion, type cross modulation distortion at a minimum, is provided. The radio-frequency amplifier comprises a transformer which transforms an input signal from an unbalanced state to a balanced state. The amplifier further comprises at least one distortion generation circuit including a first circuit having a nonlinear element and a first delay line coupled in series, and a second circuit having an attenuation element and a second delay line coupled in series. The first and second circuits are coupled in parallel. At least one distortion generation circuit is coupled to an input, an output, and/or an intermediate point of a radio-frequency amplification stage of the radio-frequency amplifier. The first and second delay lines are configured to create a delay time change in a signal input level of a signal input to the radio-frequency amplification stage which opposes a delay time change in the signal input level caused by a delay time difference between the input and output of the radio-frequency amplification stage. A transformer transforms the amplified input signal from the balanced state back to an unbalanced state before outputting the amplified signal from the amplifier circuit. ## Claims ### Claim 1 A radio-frequency amplifier comprising: at least one distortion generation circuit including a first circuit having a nonlinear element and a first delay line coupled in series, and a second circuit having an attenuation element and a second delay line coupled in series, said first and second circuits being coupled in parallel; said at least one distortion generation circuit is coupled to at least one of an input and an output of a radio frequency amplification stage of said radio-frequency amplifier, and said first and second delay lines are configured to create a delay time change in a signal input level of a signal input to said radio-frequency amplification stage which opposes a delay time change in said signal input level caused by a delay time difference between said input and output of said radio-frequency amplification stage. ### Claim 2 (depends on 1) A radio-frequency amplifier as claimed in claim 1, comprising two of said distortion generation circuits, both of which being coupled to said input of said radio-frequency amplification stage. ### Claim 3 (depends on 1) A radio-frequency amplifier as claimed in claim 1, comprising two of said distortion generation circuits, both of which being coupled to said output of said radio-frequency amplification stage. ### Claim 4 (depends on 1) A radio-frequency amplifier as claimed in claim 1, comprising four of said distortion generation circuits, two of which being coupled to said input of said radio-frequency amplification stage and the other two of which being coupled to said output of said radio-frequency amplification stage. ### Claim 5 (depends on 1) A radio-frequency amplifier as claimed in claim 1, wherein said non-linear element is a diode and said attenuation element comprises a plurality of resistors arranged in a .pi.-type circuit. ### Claim 6 (depends on 1) A radio-frequency amplifier as claimed in claim 1, further comprising at least one of the following: a first transformer coupling said input of said radio-frequency amplification stage to said at least one distortion generation circuit; and a second transformer coupling said output of said radio-frequency amplification stage to said at least one distortion generation circuit. ### Claim 7 (depends on 1) A radio-frequency amplifier as claimed in claim 1, further comprising at least one of the following: a first transformer, said at least one distortion generation circuit coupling said input of said radio-frequency amplification stage to said first transformer; and a second transformer, said at least one distortion generation circuit coupling said output of said radio-frequency amplification stage to said second transformer. ### Claim 8 (depends on 1) A radio-frequency amplifier as claimed in claim 1, wherein said at least one distortion generation circuit is coupled to said at least one of said input and output in series with a signal propagation direction of said input signal through said radio-frequency amplification stage. ### Claim 9 (depends on 1) A radio-frequency amplifier as claimed in claim 1, wherein said at least one distortion generation circuit reduces at least one of composite triple beat (CTB) distortion, amplitude type cross modulation distortion, and phase type cross modulation distortion of said input signal propagating through said amplifier. ### Claim 10 A radio-frequency amplifier comprising: at least one distortion generation circuit including a first circuit having a nonlinear element and a first delay line coupled in series, and a second circuit having an attenuation element and a second delay line coupled in series, said first and second circuits being coupled in parallel; said at least one distortion generation circuit is coupled at an intermediate point between amplification devices of a radio-frequency amplification stage, and said first and second delay lines are configured to create a delay time change in a signal input level of a signal input to said radio-frequency amplification stage which opposes a delay time change in said signal input level caused by a delay time difference between said input and output of said radio-frequency amplification stage. ### Claim 11 (depends on 10) A radio-frequency amplifier as claimed in claim 10, comprising two of said distortion generation circuits, both of which being coupled to said intermediate point. ### Claim 12 (depends on 10) A radio-frequency amplifier as claimed in claim 10, wherein said at least one distortion generation circuit is coupled to at least one of an input and an output of a radio-frequency amplification stage of said radio-frequency amplifier. ### Claim 13 (depends on 10) A radio-frequency amplifier as claimed in claim 10, wherein said non-linear element is a diode and said attenuation element comprises a plurality of resistors arranged in a .pi.-type circuit. ### Claim 14 (depends on 10) A radio-frequency amplifier as claimed in claim 10, wherein said at least one distortion generation circuit is coupled at said intermediate point in series with a signal propagation direction of said input signal through said radio-frequency amplification stage. ### Claim 15 (depends on 10) A radio-frequency amplifier as claimed in claim 10, wherein said at least one distortion generation circuit reduces at least one of composite triple beat (CTB) distortion, amplitude type cross modulation distortion, and phase type cross modulation distortion of said input signal propagating through said amplifier. ### Claim 16 A distortion generation circuit, for use with a radio-frequency amplifier, comprising: a first circuit having a nonlinear element and a first delay line coupled in series; and a second circuit having an attenuation element and a second delay line coupled in series, said first and second circuits being coupled in parallel, wherein said first and second circuits have different delay times with respect to each other. ### Claim 17 (depends on 16) A distortion generation circuit as claimed in claim 16, wherein said non-linear element is a diode and said attenuation element comprises a plurality of resistors arranged in a .pi.-type circuit. ### Claim 18 A method for reducing at least one of amplitude type cross modulation distortion, phase type cross modulation distortion and composite triple beat (CTB) distortion of an input signal propagating through a radio-frequency amplifier, comprising the steps of: amplifying said input signal to create and amplified signal; generating a distortion in said input signal at least one of at time prior to amplifying said input signal, during amplification of said input signal, and after amplifying said input signal, to effect a delay time in a signal input level of said input signal to oppose a delay time change in said signal input level caused by a delay time difference between an input and output of said radio-frequency amplifier; and outputting said amplified signal from said radio-frequency amplifier. ### Claim 19 (depends on 18) A method as claimed in claim 18, further comprising the step of transforming said input signal from an unbalanced state into a balanced state at least one of prior to and after generating distortion in said input signal. ### Claim 20 (depends on 19) A method as claimed in claim 19, wherein said input signal is amplified during said amplification step in said balanced state, and further comprising the step of transforming said amplified signal from said balanced state to an unbalanced state prior to outputting said amplified signal. ### Claim 21 An integrated circuit comprising a radio-frequency amplifier circuit, said radio-frequency amplifier including: at least one distortion generation circuit including a first circuit having a nonlinear element and a first delay line coupled in series, and a second circuit having an attenuation element and a second delay line coupled in series, said first and second circuits being coupled in parallel; said at least one distortion generation circuit is coupled to at least one of an input and an output of a radio-frequency amplification stage of said radio-frequency amplifier, and said first and second delay lines are configured to create a delay time change in a signal input level of a signal input to said radio-frequency amplification stage which opposes a delay time change in said signal input level caused by a delay time difference between said input and output of said radio-frequency amplification stage. ### Claim 22 (depends on 21) An integrated circuit as claimed in claim 21, comprising two of said distortion generation circuits, both of which being coupled to said input of said radio-frequency amplification stage. ### Claim 23 (depends on 21) An integrated circuit as claimed in claim 21, comprising two of said distortion generation circuits, both of which being coupled to said output of said radio-frequency amplification stage. ### Claim 24 (depends on 21) An integrated circuit as claimed in claim 21, comprising four of said distortion generation circuits, two of which being coupled to said input of said radio-frequency amplification stage and the other two of which being coupled to said output of said radio-frequency amplification stage. ### Claim 25 (depends on 21) An integrated circuit as claimed in claim 21, wherein said non-linear element is a diode and said attenuation element comprises a plurality of resistors arranged in a .pi.-type circuit. ### Claim 26 (depends on 21) An integrated circuit as claimed in claim 21, further comprising at least one of the following: a first transformer coupling said input of said radio-frequency amplification stage to said at least one distortion generation circuit; and a second transformer coupling said output of said radio-frequency amplification stage to said at least one distortion generation circuit. ### Claim 27 (depends on 21) An integrated circuit as claimed in claim 21, further comprising at least one of the following: a first transformer, said at least one distortion generation circuit coupling said input of said radio-frequency amplification stage to said first transformer; and a second transformer, said at least one distortion generation circuit coupling said output of said radio-frequency amplification stage to said second transformer. ### Claim 28 (depends on 21) An integrated circuit as claimed in claim 21, wherein said at least one distortion generation circuit is coupled to said at least one of said input and output in series with a signal propagation direction of said input signal through said radio-frequency amplification stage. ### Claim 29 (depends on 21) An integrated circuit as claimed in claim 21, wherein said at least one distortion generation circuit reduces at least one of composite triple beat (CTB) distortion, amplitude type cross modulation distortion, and phase type cross modulation distortion of said input signal propagating through said amplifier. ### Claim 30 An integrated circuit comprising a radio-frequency amplifier circuit, said radio-frequency amplifier including: at least one distortion generation circuit including a first circuit having a nonlinear element and a first delay line coupled in series, and a second circuit having an attenuation element and a second delay line coupled in series, said first and second circuits being coupled in parallel; said at least one distortion generation circuit is coupled at an intermediate point between amplification devices of a radio-frequency amplification stage, and said first and second delay lines are configured to create a delay time change in a signal input level of a signal input to said radio-frequency amplification stage which opposes a delay time change in said signal input level caused by a delay time difference between said input and output of said radio-frequency amplification stage. ### Claim 31 (depends on 30) An integrated circuit as claimed in claim 30, comprising two of said distortion generation circuits, both of which being coupled to said intermediate point. ### Claim 32 (depends on 30) An integrated circuit as claimed in claim 30, wherein said at least one distortion generation circuit is coupled to at least one of an input and an output of a radio-frequency amplification stage of said radio-frequency amplifier. ### Claim 33 (depends on 30) An integrated circuit as claimed in claim 30, wherein said non-linear element is a diode and said attenuation element comprises a plurality of resistors arranged in a .pi.-type circuit. ### Claim 34 (depends on 30) An integrated circuit as claimed in claim 30, wherein said at least one distortion generation circuit is coupled at said intermediate point in series with a signal propagation direction of said input signal through said radio-frequency amplification stage. ### Claim 35 (depends on 30) An integrated circuit as claimed in claim 30, wherein said at least one distortion generation circuit reduces at least one of composite triple beat (CTB) distortion, amplitude type cross modulation distortion, and phase type cross modulation distortion of said input signal propagating through said amplifier. ### Claim 36 An integrated circuit comprising a distortion generation circuit, said distortion circuit comprising: a first circuit having a nonlinear element and a first delay lined coupled in series; and a second circuit having an attenuation element and a second delay line coupled in series, said first and second circuits being coupled in parallel, wherein said first and second circuits have different delay times with respect to each other. ### Claim 37 (depends on 36) An integrated circuit as claimed in claim 36, wherein said non-linear element is a diode and said attenuation element comprises a plurality of resistors arranged in a K-type circuit.