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AssigneeNokia Mobile Phones Ltd.
InventorsThomas J. Kenney, Ilkka Niva, Steven D. Gray, Joe Dowling
Estimating the term…
In the front end of a CDMA cellular or broadband PCS mobile phone receiver, a switched bypass connection is provided to bypass the low noise amplifier, sending the received signal through an amplifier bypass connection. The amplifier bypass connection may include an attenuator. The switched bypass is activated by a control signal generated by a digital signal processor. The digital signal processor analyzes the received signal to detect and determine the relative contribution of the IMD interference to the total received signal power and, when the IMD interference exceeds a predetermined level, sends a control signal to bypass the low noise amplifier. Identification of the presence of IMD interference is by spectral estimation to discern when the mobile phone is in the presence of large near-band signals from an AMPS or other narrow-band base station which causes in-band IMD. In a preferred embodiment, the spectral estimation is performed by collecting a series of data samples from the received signal and, using a digital signal processor (DSP), computing a Discrete Fourier Transform (DFT) to generate frequency domain data, passing the data through a filter bank, then using a decision algorithm to determine whether or not there is sufficient IMD present in the received signal to bypass the LNA. If the IMD level is high enough to warrant bypass of the LNA, the DSP will provide a signal to an automatic gain control (AGC) block for controlling a variable gain amplifier (VGA) to compensate for gain loss due to bypass of the LNA.
A device for detecting and reducing in-band intermodulation distortion in a broadband-based mobile phone comprising:
A method for detecting an in-band interfering signal within a broad bandwidth receive signal comprising:
In a mobile phone receiver having a low noise amplifier and a digital signal processor, a method for detecting and reducing distortion products resulting from a high level narrow-band interfering signal which produces in-band interference within a broad bandwidth receive signal, the method comprising:
In a conventional CDMA mobile phone receiver front end having a low noise amplifier, and at least one digital-to-analog converter for converting an analog received signal within a CDMA bandwidth to a digital signal which is passed to a digital signal processor, a method for detecting in-band intermodulation distortion comprising:
A method of detecting in-band intermodulation distortion in a CDMA receiver, the method comprising the steps of:
A method of reducing in-band intermodulation distortion in a CDMA receiver receiving a CDMA bandwidth at a low noise amplifier of the receiver, the method comprising the steps of:
A device for reducing in-band intermodulation distortion in an broadband receiver, the device comprising:
Dependencies are inferred from the claim text.