Calibration of transmit signals in FDD-transceivers
First Claim
1. A method of calibration of a transmit signal to be transmitted in a device simultaneously receiving and transmitting signals in a communication system, which device comprises a receiving path for a receive signal (RXS), a transmit path for the transmit signal (TXS), a calibration path for a correction signal (CS), the transmit signal being also received in the receiving path and the transmit signal and the receive signal being separated by a predetermined frequency band gap, wherein the transmit signal (TXS) is inserted or leaks into the receiving path as a received transmit signal, the method comprising:
- down-converting the received transmit signal to an intermediate frequency by mixing the received transmit signal with a first local oscillator frequency in the receiving path, wherein the intermediate frequency substantially corresponds to the frequency band gap reduced by the intermediate frequency of the receive signal;
deriving an analog correction signal from the received transmit signal converted down in the down-converting step, wherein the deriving step is performed in the calibration path; and
calibrating the transmit signal by a one of acting with the analog correction signal on the transmit path upon the transmit signal and converting the analog correction signal into a digital correction signal and calibrating the transmit signal by acting with the digital correction signal on the transmit path in the digital domain upon the digital transmit signal to be transmitted.
4 Assignments
0 Petitions
Accused Products
Abstract
By the present invention a calibration and/or correction of transmit signals in a communication system using Frequency Division Duplex has been disclosed, in particular a method of calibration of a transmit signal to be transmitted in a device simultaneously receiving and transmitting signals in the communication system, wherein the transmit signal and the receive signal are separated by a predetermined frequency band gap. A down-conversion of the transmit signal received in the receiving path to an intermediate frequency is performed, whereby the intermediate frequency corresponds to the frequency band gap reduced by the intermediate frequency of the receive signal. A correction signal is derived from the intermediate received transmit signal and used to calibrate the transmit signal such that non-linearity effects caused by power amplifiers in the transmit path are effectively reduced. The present invention provides the advantages of an improved and simplified architecture and simultaneously of a clearly improved quality of transmit signals.
-
Citations
14 Claims
-
1. A method of calibration of a transmit signal to be transmitted in a device simultaneously receiving and transmitting signals in a communication system, which device comprises a receiving path for a receive signal (RXS), a transmit path for the transmit signal (TXS), a calibration path for a correction signal (CS), the transmit signal being also received in the receiving path and the transmit signal and the receive signal being separated by a predetermined frequency band gap, wherein the transmit signal (TXS) is inserted or leaks into the receiving path as a received transmit signal, the method comprising:
-
down-converting the received transmit signal to an intermediate frequency by mixing the received transmit signal with a first local oscillator frequency in the receiving path, wherein the intermediate frequency substantially corresponds to the frequency band gap reduced by the intermediate frequency of the receive signal; deriving an analog correction signal from the received transmit signal converted down in the down-converting step, wherein the deriving step is performed in the calibration path; and calibrating the transmit signal by a one of acting with the analog correction signal on the transmit path upon the transmit signal and converting the analog correction signal into a digital correction signal and calibrating the transmit signal by acting with the digital correction signal on the transmit path in the digital domain upon the digital transmit signal to be transmitted. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. A transceiver simultaneously receiving and transmitting signals in a communication system, wherein the transceiver comprises a receiving path for a receive signal;
- a transmit path for a transmit signal; and
a calibration path for a correction signal, wherein the transmit signal and the receive signal being separated by a predetermined frequency band gap and the transmit signal being also received in the receiving path, which device comprises;down-conversion means arranged to down convert the received transmit signal to an intermediate frequency by mixing the received transmit signal with a first local oscillator frequency in the receiving path, wherein the intermediate frequency corresponds substantially to the frequency band gap reduced by the intermediate frequency of the receive signal; deriving means arranged to derive an analog correction signal as the correction signal in the conversion path from the received transmit signal converted down by the down-conversion means; calibrating means arranged to calibrate the transmit signal by acting with the analog correction signal on the transmit path upon the transmit signal; means arranged to convert the analog correction signal into a digital signal; and means arranged to calibrate the transmit signal to be transmitted by acting upon the transmit signal to be transmitted with the digital correction signal on the transmit path in the digital domain. - View Dependent Claims (10, 11, 12, 13, 14)
- a transmit path for a transmit signal; and
Specification