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Transmitter leakage cancellation circuit with low power consumption

IP.com Disclosure Number: IPCOM000130311D
Original Publication Date: 2005-Nov-25
Included in the Prior Art Database: 2005-Nov-25
Document File: 2 page(s) / 64K

Publishing Venue

Siemens

Related People

Juergen Carstens: CONTACT

Abstract

The given application is directed to decrease an average power consumption of the full duplex transceiver chip with the cancellation circuit of the transmitter leakage signal that is especially actual in mobile devices (e.g. UMTS (Universal Mobile Telecommunications System) cellular telephones). Up to now, when output power of the transmitter is small (less than 0 dBm), cancellation is not required, and all cancellation circuits are switched into a sleeping mode with reduced power consumption. The disadvantage hereby is, when the output power of the transmitter is greater than 0 dBm, the cancellation circuit starts to work. After finishing of tuning and reaching a specific cancellation degree, the measuring part of the cancellation circuit (LO (Local Oscillator) divider, mixer, LPF (Low Pass Filter), detector and ADC (Analog to Digital Converter)) continues to work in a former mode with full power consumption to monitor any modification of an antenna mismatch, after which it will be necessary to begin a new tuning cycle.

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Transmitter leakage cancellation circuit with low power consumption

Idea: Dr. Grigory Itkin, DE-Munich; Dr. Oleg Varlamov, RU-Moskow; Nikolai Filimonov, RU-Moskow

The given application is directed to decrease an average power consumption of the full duplex transceiver chip with the cancellation circuit of the transmitter leakage signal that is especially actual in mobile devices (e.g. UMTS (Universal Mobile Telecommunications System) cellular telephones).

Up to now, when output power of the transmitter is small (less than 0 dBm), cancellation is not required, and all cancellation circuits are switched into a sleeping mode with reduced power consumption.

The disadvantage hereby is, when the output power of the transmitter is greater than 0 dBm, the cancellation circuit starts to work. After finishing of tuning and reaching a specific cancellation degree, the measuring part of the cancellation circuit (LO (Local Oscillator) divider, mixer, LPF (Low Pass Filter), detector and ADC (Analog to Digital Converter)) continues to work in a former mode with full power consumption to monitor any modification of an antenna mismatch, after which it will be necessary to begin a new tuning cycle.

During tuning procedure the measuring part of the cancellation circuit should work with a high precision and fast speed to reach convergence of tuning algorithm in specific time. Therefore, blocks of the measuring part of the cancellation circuit usually have high current consumption. After reaching a specific degree of cancellation, the cancellation circuit should monitor any modification of an antenna mismatch, after which it will be necessary to begin a new tuning cycle. The modification of an antenna mismatch happens much more slowly (tens of milliseconds), than the duration of tuning cycle of the cancellation circuit. Between tuning cycles the measuring part of the cancellation circuit can be switched off (transferred in the sleeping mode). To detect any modification of system parameters and to begin a new tuning cycle in the cancellation circuit, low power consumpting RF detector and comparator are added....