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US 7,783,273 B2Granted
Method and system for calibrating frequencies-amplitude and phase mismatch in a receiver
AssigneeRenasas Electronics Corporation
InventorsKoji Maeda, Satoshi Tanaka, Yukinori Akamine, Manabu Kawabe
Life of this patent
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Abstract
The receiver, which enables rejection of image signals with higher accuracy over wider frequency band, can be provided as a low IF receiver by inputting a calibration signal of frequency fi (1≦i≦N) before reception of signals and determining the frequency response fa(z) to fd(z) of a calibrating filter in a filter mismatch calibrating circuit (FIL_CAL) 195 to make zero amplitude and phase mismatches between the I component and Q component of the quadrature demodulation signal at the frequency fIFi.
Claims20
A receiver comprising:
- a quadrature mixer for providing a pair of demodulation outputs of I component and Q component substantially quadrature from a received RF signal and
- a local signal for receiving;
- and
- a phase/amplitude calibrating unit for calibrating amplitude mismatch and phase mismatch between the pair of demodulation outputs, the phase/amplitude calibrating unit including a calibrating filter, wherein
- the phase/amplitude calibrating unit has a function to set image rejection ratios at the setting points of a plurality of frequencies in multiple channels of the received signal using the calibrating filter so that an image rejection ratio (IRR) of the image interfering signal for the plurality of frequencies in the multiple channels of the received signal within a frequency band of the quadrature mixer output satisfies the standards required for the receiver.
2 more elements
A receiver comprising:
- a quadrature mixer for generating a couple of demodulation outputs of I component and Q component substantially quadrature from a received RF signal and
- a local signal for receiving;
- an I component signal path;
- a Q component signal path;
- and
- a phase/amplitude calibrating unit for calibrating amplitude mismatch and phase mismatch of the I component and Q component, wherein
- the phase/amplitude calibrating unit includes a calibrating filter having a frequency response fi,(z), and has a function to determine the frequency response of the calibrating filter using calibration signals of a plurality of frequencies fi, in order to make zero, amplitude and phase mismatches of the I and Q components in the I component signal path and Q component signal path at a plurality of frequencies fIFi, within a desired frequency band satisfying a relevant standard of the receiver.
4 more elements
A receiver comprising:
- a quadrature mixer for generating a pair of demodulation outputs of I component and Q component substantially quadrature from a received RF signal and
- a local signal for receiving;
- a phase/amplitude calibrating unit for calibrating amplitude mismatch and phase mismatch of the I component and Q component, the phase/amplitude calibrating unit including a calibrating filter;
- and
- an image rejecting circuit for frequency-converting the received signal to the baseband from the IF band,
- wherein the phase/amplitude calibrating unit has a function to set image rejection ratios at the setting points of a plurality of frequencies in multiple channels of the received signal using the calibrating filter so that an image rejection ratio (IRR) of the image interfering signal for the plurality of frequencies in the multiple channels of the received signal in the frequency band in the input side of the image rejecting circuit satisfies the standards required for the receiver.
3 more elements
Dependencies are inferred from the claim text.