# US 2022/0286151 A1 · Linearizing narrowband carriers with low resolution predistorters > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2022/0286151 A1 - Document ID: US20220286151A1 - Status: Published application - Kind: A1 - Application number: 17/193,939 - Filed: 2021-03-05 - Published: 2022-09-08 - Earliest claimed: 2021-03-05 - Assignees: Motorola Solutions, Inc. - Applicants: Motorola Solutions, Inc. - Inventors: Rodney W. Hagen; Gregory J. Buchwald; Dennis M. Drees; In S. Kim; Arthur Christopher Leyh - Web page: https://patentgrep.com/patent/US20220286151A1 ## CPC - H04B 1/04: Circuits - H04B 1/0475: {with means for limiting noise, interference or distortion (H04B1/0483 takes precedence)} - H04B 1/1036: {with automatic suppression of narrow band noise or interference, e.g. by using tuneable notch filters (H04B1/123 takes precedence; filter circuits H03H)} - H04B 17/318: Received signal strength - H04B 2001/0425: {with linearisation using predistortion} - H04B 2001/0433: {with linearisation using feedback} - H04B 2001/0491: {with frequency synthesizers, frequency converters or modulators} - H04B: TRANSMISSION ## Abstract Apparatus and method for linearizing narrowband carriers with low resolution predistorters are provided. The method includes amplifying, using a power amplifier, one or more broadcast carriers and linearizing, using a predistorter coupled to the power amplifier, the one or more broadcast carriers. The method also includes determining, using an electronic processor, a composite bandwidth of the one or more broadcast carriers and determining, using the electronic processor, whether the composite bandwidth is below a modulation bandwidth of the predistorter. The method further includes controlling, using the electronic processor, a pacification carrier generator coupled to the electronic processor to combine a pacification carrier with the one or more broadcast carriers when the composite bandwidth is below the minimum modulation bandwidth of the predistorter. ## Claims ### Claim 1 A radio frequency (RF) system for linearizing narrowband carriers with low resolution predistorters, the system comprising: a power amplifier configured to amplify one or more broadcast carriers; a predistorter coupled to the power amplifier and configured to linearize the one or more broadcast carriers; and a pacification carrier generator configured to generate a pacification carrier, wherein the pacification carrier is combined with the one or more broadcast carriers to satisfy a minimum modulation bandwidth of the predistorter. ### Claim 2 (depends on 1) The RF system of claim 1, further comprising: an electronic processor coupled to the pacification carrier and configured to: determine a composite bandwidth of the one or more broadcast carriers, determine whether the composite bandwidth is below a minimum modulation bandwidth of the predistorter, and control the pacification carrier generator to combine the pacification carrier with the one or more broadcast carriers when the composite bandwidth is below the minimum modulation bandwidth of the predistorter. ### Claim 3 (depends on 2) The RF system of claim 2, wherein the electronic processor is configured to control the pacification carrier generator to stop generation of the pacification carrier when the composite bandwidth is above the minimum modulation bandwidth of the predistorter. ### Claim 4 (depends on 2) The RF system of claim 2, wherein the minimum modulation bandwidth of the predistorter is above 1 MHz and wherein the electronic processor is further configured to combine the pacification carrier with the one or more broadcast carriers resulting in a combined signal having a bandwidth greater than 1 MHz. ### Claim 5 (depends on 1) The RF system of claim 1, further comprising: a transmission post filter configured to filter an amplified signal received from the power amplifier, wherein the transmission post filter attenuates the pacification carrier from the amplified signal. ### Claim 6 (depends on 1) The RF system of claim 1, wherein the pacification carrier is generated at a power level 10 Decibels or more below a composite power of the one or more broadcast carriers. ### Claim 7 (depends on 2) The RF system of claim 2, wherein the electronic processor is further configured to scan through a plurality of frequencies of a transmission band of the RF system; measure a received signal strength indicator (RSSI) of signals detected at each of the plurality of frequencies; determine a number of the plurality of frequencies for which the RSSI exceeds a threshold RSSI; and determine whether the number of the plurality of frequencies exceeds a threshold number. ### Claim 8 (depends on 7) The RF system of claim 7, wherein the electronic processor is configured to: determine that the composite bandwidth is below the minimum modulation bandwidth when the number of the plurality of frequencies does not exceed the threshold number; and determine that the composite bandwidth exceeds the minimum modulation bandwidth when the number of the plurality of frequencies exceeds the threshold number. ### Claim 9 (depends on 7) The RF system of claim 7, further comprising a detection antenna coupled to the electronic processor and configured to detect the one or more broadcast carriers transmitted by the RF system, wherein the electronic processor is configured to measure the RSSI based on signals detected at the detection antenna. ### Claim 10 (depends on 7) The RF system of claim 7, further comprising a detection coupler coupled to the electronic processor and configured to detect the one or more broadcast carriers transmitted by the RF system, wherein the electronic processor is configured to measure the RSSI based on signals detected at the detection coupler. ### Claim 11 (depends on 2) The RF system of claim 2, wherein the electronic processor is further configured to measure a characteristic of the one or more broadcast carriers; compare the characteristic to a predetermined characteristic threshold; determine that the composite bandwidth is below the minimum modulation bandwidth when the characteristic does not satisfy the predetermined characteristic threshold; and determine that the composite bandwidth is above the minimum modulation bandwidth when the characteristic satisfies the predetermined characteristic threshold. ### Claim 12 (depends on 1) The RF system of claim 1, wherein the narrowband carriers include 200 kHz internet of things (IoT) carriers. ### Claim 13 A method for linearizing narrowband carriers with low resolution predistorters, the method comprising: amplifying, using a power amplifier, one or more broadcast carriers; linearizing, using a predistorter coupled to the power amplifier, the one or more broadcast carriers; and generating, using a pacification carrier generator, a pacification carrier, wherein the pacification carrier is combined with the one or more broadcast carriers to satisfy a minimum modulation bandwidth of the predistorter. ### Claim 14 (depends on 13) The method of claim 13, further comprising: determining, using an electronic processor, a composite bandwidth of the one or more broadcast carriers; determining, using the electronic processor, whether the composite bandwidth is below a minimum modulation bandwidth of the predistorter; and controlling, using the electronic processor, the pacification carrier generator coupled to the electronic processor to combine the pacification carrier with the one or more broadcast carriers when the composite bandwidth is below the minimum modulation bandwidth of the predistorter. ### Claim 15 (depends on 14) The method of claim 14, further comprising controlling, using the electronic processor, the pacification carrier generator to stop generation of the pacification carrier when the composite bandwidth is above the minimum modulation bandwidth of the predistorter. ### Claim 16 (depends on 14) The method of claim 14, wherein the minimum modulation bandwidth of the predistorter is above 1 MHz, the method further comprising: combining, using the electronic processor, the pacification carrier with the one or more broadcast carriers resulting in a combined signal having a bandwidth greater than 1 MHz. ### Claim 17 (depends on 13) The method of claim 13, further comprising: attenuating, using a transmission post filter, the pacification carrier from an amplified signal. ### Claim 18 (depends on 13) The method of claim 13, wherein the pacification carrier is generated at a power level 10 Decibels or more below a composite power of the one or more broadcast carriers. ### Claim 19 (depends on 14) The method of claim 14, further comprising: scanning, using the electronic processor, through a plurality of frequencies of a transmission band of the RF system; measuring, using the electronic processor, a received signal strength indicator (RSSI) of signals detected at each of the plurality of frequencies; determining, using the electronic processor, a number of the plurality of frequencies for which the RSSI exceeds a threshold RSSI; and determining, using the electronic processor, whether the number of the plurality of frequencies exceeds a threshold number. ### Claim 20 (depends on 19) The method of claim 19, further comprising: determining, using the electronic processor, that the composite bandwidth is below the minimum modulation bandwidth when the number of the plurality of frequencies does not exceed the threshold number; and determining, using the electronic processor that the composite bandwidth exceeds the minimum modulation bandwidth when the number of the plurality of frequencies exceeds the threshold number. ### Claim 21 (depends on 19) The method of claim 19, further comprising: measuring, using a detection antenna coupled to the electronic processor, the RSSI based on signals detected at the detection antenna. ### Claim 22 (depends on 19) The method of claim 19, further comprising: measuring, using a detection coupler, the RSSI based on signals detected at the detection coupler. ### Claim 23 (depends on 14) The method of claim 14, further comprising: measuring, using the electronic processor, a characteristic of the one or more broadcast carriers; comparing, using the electronic processor, the characteristic to a predetermined characteristic threshold; determining, using the electronic processor, that the composite bandwidth is below the minimum modulation bandwidth when the characteristic does not satisfy the predetermined characteristic threshold; and determining, using the electronic processor, that the composite bandwidth is above the minimum modulation bandwidth when the characteristic satisfies the predetermined characteristic threshold. ### Claim 24 (depends on 13) The method of claim 13, wherein the narrowband carriers include 200 kHz internet of things (IoT) carriers.