Pulse or digital communications – Receivers
Reexamination Certificate
1998-03-27
2001-07-03
Chin, Stephen (Department: 2631)
Pulse or digital communications
Receivers
C455S144000, C455S142000, C455S130000, C329S315000, C329S347000, C329S372000
Reexamination Certificate
active
06256358
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates in general to digital signal processor integrated circuits, and more specifically, to a processing architecture having reconfigurable blocks to minimize integrated circuit area required to process multi-band radio signals, such as AM and FM.
With the advent of high speed digital signal processing (DSP) components, radio receivers are being introduced using DSP integrated circuits to implement demodulation and various other functions in a radio receiver. In particular, it is becoming possible to digitally process the intermediate frequency (IF) signal or even the radio frequency (RF) signal, thus avoiding a large number of analog circuits and components with their associated costs and space requirements. In order to keep costs down for a particular audio system, DSP performance in terms of 1) chip area required for processing, and 2) execution time, each need to be minimized.
DSP components are typically organized into blocks, each block performing a particular function such as decimating, filtering, or signal detection. In a multi-band radio receiver, the exact functions which must be performed to reproduce each different type of broadcast may be significantly different. For example, AM and FM broadcast signals are transmitted using different types of modulation and different bandwidths. Consequently, separate chains of processing blocks have been used in prior art DSP components to separately process AM and FM signals. This inefficient use of DSP chip area results in higher costs both for the DSP integrated circuits themselves and the audio systems which use them.
SUMMARY OF THE INVENTION
The present invention has the advantage of using a single chain of processing blocks in a DSP architecture for processing multi-band radio signals.
In a preferred embodiment, the present invention provides a digital signal processor for a multi-band radio receiver that processes audio signals from a radio tuner including a narrowband IF signal from a first broadcast band and a wideband IF signal from a second broadcast band. A half-complex mixer block is selectively responsive to the narrowband IF signal when the processor is in a narrowband mode, or the wideband IF signal when the processor is in a wideband mode, and generates a digital complex IF signal at a predetermined IF frequency and at a first sample rate. The complex IF signal includes an in-phase component and a quadrature-phase component. A decimator block having dual sections coupled to the half-complex mixer block decimates the respective in-phase and quadrature-phase components of the complex IF signal by a predetermined ratio. This produces a sample-rate reduced complex IF signal at a second sample rate. A reconfigurable digital filter block has dual sections each having selectable sets of filter coefficients. A first set of coefficients corresponds to the narrowband mode and a second set corresponds to the wideband mode. The first set of filter coefficients configures the digital filter block as a decimator to further reduce the sample rate of the sample-rate reduced complex IF signal to a third sample rate when in the narrowband mode. The second set of filter coefficients configures the digital filter block as a channel lowpass filter to reject undesired signals from the sample-rate reduced complex IF signal without further sample rate reduction when in the wideband mode. A programmable processor block receives outputs from the dual sections of the digital filter block. The programmable processor block includes a program memory and a program sequencer. The program memory contains a first executable code block for use in the narrowband mode and a second executable code block for use in the wideband mode. The first executable code block performs a channel filtering and narrowband detection function at the third sample rate. The second executable code block performs a wideband detection function at the second sample rate.
REFERENCES:
patent: 3639848 (1972-02-01), Elliott
patent: 4470147 (1984-09-01), Goatcher
patent: 4592074 (1986-05-01), Whikehart
patent: 4731796 (1988-03-01), Masterton et al.
patent: 4893316 (1990-01-01), Janc et al.
patent: 5375146 (1994-12-01), Chalmers
patent: 5490173 (1996-02-01), Whikehart et al.
patent: 5640424 (1997-06-01), Banavong et al.
patent: 5640698 (1997-06-01), Shen et al.
patent: 5732337 (1998-03-01), Wargnier et al.
patent: 5859878 (1999-01-01), Phillips et al.
patent: 0 254 844 A2 (1987-06-01), None
patent: 0 924 864 A2 (1999-06-01), None
patent: 2 114 840 (1982-02-01), None
patent: 2 114 840 (1982-08-01), None
patent: 0 254 844 A2 (1986-06-01), None
patent: 86/05936 (1986-10-01), None
patent: 87/07099 (1987-11-01), None
Arthur G. Stephenson, “Digitizing Multiple RF Signals Requires an Optimum Sampling Rate” Electronics, Mar. 27, 1972.*
Hosking, Roger H., Digital Receivers: The New Wave for Signal Analysis, RF Design, Apr. 1997, Atlanta GA.*
Olmstead, Clay and Petrowski, Mike, Digital IF Processing, RF Design, Sep. 1994, Atlantia, GA*
Hosking, Rodger H, Digital receivers: The new wave for signal analysis, RF Design, Apr., 1997, Atlanta, GA.
Olmstead/Petrowski, Harris Semiconductor, Digital IF Processing, RF Design, Sep., 1994, Atlanta GA.
Entertainment and information merge in the automobile, William C. Spelman, IEEE Vehicular Technology Society News, Feb., 1996, pp. 49-55.
Ballard Bradley Anderson
Difiore Nicholas Lawrence
Hagan Christopher John
Wargnier James Alfred
Whikehart J. William
Chin Stephen
Mollon Mark
Rupert Paul N
Visteon Global Technologies Inc.
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