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US 2007/0080835 A1Published application
Receiver
AssigneeRenasas Electronics Corporation
InventorsKoji Maeda, Satoshi Tanaka, Yukinori Akamine, Manabu Kawabe
Life of this patent
Estimating the term…
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 couple 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 a couple of the demodulation outputs, wherein
- the phase/amplitude calibrating unit has a function to set image rejection ratios at the setting points of a plurality of frequencies in a desired frequency band so that an image rejection ratio (IRR) of the image interfering signal for the desired received signal within the frequency band of the quadrature mixer output satisfies the standards required for the receiver.
1 more element
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.
3 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;
- a phase/amplitude calibrating unit for calibrating amplitude mismatch and phase mismatch of the I component and Q component;
- 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 a desired frequency band so that an image rejection ratio (IRR) of the image interfering signal for the desired received signal in the frequency band in the input side of the image rejecting circuit satisfies the standards required for the receiver.
2 more elements
Dependencies are inferred from the claim text.