# US 2013/0156083 A1 · Adaptive Compensation of Nonlinear Frequency Distortion in Polar Transmitters Based on a Least Squares Estimation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0156083 A1 - Document ID: US20130156083A1 - Status: Published application - Kind: A1 - Application number: 13/326,749 - Filed: 2011-12-15 - Published: 2013-06-20 - Earliest claimed: 2011-12-15 - Assignees: Intel Mobile Communications GmbH - Inventors: Bruno Jechoux; Giuseppe Li Puma; Yanzhong Dai - Web page: https://patentgrep.com/patent/US20130156083A1 ## CPC - H04L 27/3809: {Amplitude regulation arrangements} - H04L 27/3872: {Compensation for phase rotation in the demodulated signal} - H04L 27/389: {with separate demodulation for the phase and amplitude components} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract The present invention relates to a communication system having a digital to analog converter, a first input, a summation component, and a compensation unit. The converter is configured to receive a first. The first input is configured to receive a phase modulation signal. The compensation unit includes one or more inputs and is configured to measure amplitude samples of the first signal at a first of the one or more inputs and to generate a correction signal according to the one or more inputs. The correction signal at least partially accounts for estimated distortions of the phase modulation signal from the amplitude modulation path. The summation component is configured to receive the phase modulation signal and the correction signal and to generate a corrected phase modulation signal as a result. ## Claims ### Claim 1 A communication system comprising: a digital to analog converter configured to receive a first signal; a first input configured to receive a phase modulation signal; a compensation unit having one or more inputs, the compensation unit configured to obtain amplitude samples of first signal at a first input of the one or more inputs and generate a correction signal according to the one or more inputs, wherein the correction signal accounts for distortions from an amplitude modulation path; and a summation component configured to receive the phase modulation signal and the correction signal and to generate a corrected phase modulation signal there from. ### Claim 2 (depends on 1) The system of claim 1, further comprising digital phase locked loop circuit configured to generate a carrier phase modulation signal from the corrected phase modulation signal. ### Claim 3 (depends on 2) The system of claim 2, wherein the digital phase locked loop circuit is further configured to provide a frequency deviation signal to a second input of the one or more inputs of the compensation unit. ### Claim 4 (depends on 3) The system of claim 3, wherein the frequency deviation signal represents an instantaneous frequency deviation of the phase modulation signal. ### Claim 5 (depends on 3) The system of claim 3, wherein the compensation unit is configured to receive a transmission power signal at a third input of the one or more inputs, and the compensation unit scales the correction signal according to the transmission power. ### Claim 6 (depends on 1) The system of claim 1, wherein the first signal and the phase modulation signal are of a communication sequence having a first portion and a second portion, wherein the compensation unit is configured to develop a frequency distortion estimate during a first portion of communication sequence and utilizes the distortion estimate during a second portion of the communication sequence to generate the correction signal. ### Claim 7 (depends on 6) The system of claim 6, wherein the first portion is a magnitude ramping portion and the second portion is a data transfer portion. ### Claim 8 (depends on 6) The system of claim 6, wherein the compensation unit is configured to utilize a least squares estimation to develop the frequency distortion estimate. ### Claim 9 (depends on 6) The system of claim 6, wherein the compensation unit is configured to include a lookup table and to utilize the lookup table to develop the frequency distortion estimate. ### Claim 10 (depends on 9) The system of claim 9, wherein the first signal is an amplitude modulation signal and a current amplitude sample of the amplitude modulation signal identifies an entry in the lookup table and the identified entry is utilized to generate the distortion estimate. ### Claim 11 (depends on 6) The system of claim 6, wherein the compensation unit includes a coefficient calculation component configured to develop second and third order coefficients utilized by the compensation unit to develop the amplitude distortion estimate. ### Claim 12 A communication system comprising: a converter configured to provide a phase components signal and an amplitude components signal; an interpolation component configured to generate an amplitude modulation signal from the amplitude components signal; a digital to analog converter configured to generate an amplitude carrier modulation signal from the amplitude modulation signal; a phase to frequency converter configured to generate a phase modulation signal from the phase components signal; a compensation unit having one or more inputs, the configured to receive one or more input signals and generate a correction signal according to the one or more input signals, wherein the one or more input signals include amplitude samples of the amplitude modulation signal and wherein the correction signal accounts for distortions from the amplitude modulation signal; a summation component configured to receive the phase modulation signal and the correction signal and to generate a corrected phase modulation signal there from; a digital phase locked loop configured to receive the corrected phase modulation signal and to generate a phase carrier modulation signal; and a mixer to mix the phase carrier modulation signal and the amplitude carrier modulation signal into an output transmit signal. ### Claim 13 (depends on 12) The system of claim 12, wherein the compensation unit is configured to utilize a least squares estimation to develop a distortion estimate. ### Claim 14 (depends on 13) The system of claim 13, wherein the compensation unit is configured to generate the correction signal at least partly according to the distortion estimate. ### Claim 15 (depends on 12) The system of claim 12, further comprising a coefficient estimator that generates coefficients based on ramp samples of the amplitude modulation signal and frequency deviation samples of the phase modulation signal. ### Claim 16 (depends on 15) The system of claim 15, wherein the coefficients are provided as a second input to the one or more inputs of the compensation unit. ### Claim 17 A method of estimating distortion in a communication system, the method comprising: obtaining ramp samples of a first portion of a communication sequence; obtaining frequency deviation samples of the first portion of the communication sequence; developing a distortion estimate according to the ramp samples and the deviation samples, wherein the distortion estimate estimates phase distortion resulting from an amplitude modulation path; and generating a correction signal according to the distortion estimate and magnitude samples of a data portion of the communication sequence. ### Claim 18 (depends on 17) The method of claim 17, further comprising applying the correction signal to the communication sequence to mitigate unwanted distortions. ### Claim 19 (depends on 18) The method of claim 18, wherein applying the correction signal comprises combining the correction signal with an uncorrected phase modulated signal to yield a corrected phase modulated signal. ### Claim 20 (depends on 17) The method of claim 17, wherein the first portion is a training sequence and includes a smooth, controlled increase of transmission power.