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US 5,465,410 AGranted
Method and apparatus for automatic frequency and bandwidth control
AssigneeMotorola, Inc.
InventorsBradley M. Hiben, Donald G. Newberg, Robert D. Logalbo
Life of this patent
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Abstract
An FM receiver (100) that includes a plurality of filtering elements (120-124) that have various center frequencies and bandwidths that adjust to maximize the signal quality of a desired signal (104) recovers the desired signal (104) by inputting the desired signal (104) to each of the plurality of filtering elements (120-124). Signal recovery is performed on an output of each of the filtering elements (120-124) to obtain a plurality of recovered signals. The recovered signals are then measured to obtain a plurality of signal quality metrics for the desired signal.
Claims33
In an FM receiver configured to receive a desired signal at a frequency f1, the FM receiver including a plurality of filtering elements that each apply a filter response to an inputted signal, the plurality of filtering elements including:
- a nominal filter response having a center frequency f1 and a bandwidth B1;
- a higher frequency filter response having a center frequency f2 and a bandwidth B2, wherein f2 is substantially equal to (f1+X2), wherein X2 is a variable frequency offset and wherein B2 is substantially equal to B1;
- a lower frequency filter response having a center frequency f3 and a bandwidth B3, wherein f3 is substantially equal to (f1-X3), wherein X3 is a variable frequency offset and wherein B3 is substantially equal to B1;
- a larger bandwidth filter response having a center frequency f4 and a bandwidth B4, wherein f4 is substantially equal to f1, and wherein B4 is substantially equal to (B1+Y4), and wherein Y4 is a variable bandwidth offset;
- a smaller bandwidth filter response having a center frequency f5 and a bandwidth B5, wherein f5 is substantially equal to f1, and wherein B5 is substantially equal to (B1-Y5), and wherein Y5 is a variable bandwidth offset;
- wherein the center frequency and bandwidth for each of the plurality of filtering elements are adjustable;
- a method for recovering the desired signal, the method comprising the steps of:
- A) inputting, to each of the plurality of filtering elements, the desired signal;
- B) performing a signal recovery of the desired signal on an output of each of the plurality of filtering elements to obtain a plurality of recovered signals;
- and
- C) measuring the plurality of recovered signals to obtain a plurality of signal quality metrics for the desired signal.
8 more elements
An FM receiver configured to receive a desired signal at a frequency f1, the FM receiver comprising:
- a plurality of filters including;
- a nominal filter with a center frequency f1 and a bandwidth B1;
- a higher frequency filter with a center frequency f2 and a bandwidth B2, wherein f2 is substantially equal to (f1+X2), wherein X2 is a variable frequency offset, and wherein B2 is substantially equal to B1;
- a lower frequency filter with a center frequency f3 and a bandwidth B3, wherein f3 is substantially equal to (f1-X3), wherein X3 is a variable frequency offset, and wherein B3 is substantially equal to B1;
- a larger bandwidth filter with a center frequency f4 and a bandwidth B4, wherein f4 is substantially equal to f1, wherein B4 is substantially equal to (B1+Y4), and wherein Y4 is a variable bandwidth offset;
- a smaller bandwidth filter with a center frequency f5 and a bandwidth B5, wherein f5 is substantially equal to f1, wherein B5 is substantially equal to (B1-Y5), and wherein Y5 is a variable bandwidth offset;
- wherein the center frequency and bandwidth for each of the plurality of filters is adjustable;
- an antenna, operably coupled to an input for each of the plurality of filters;
- a plurality of signal decoders operably coupled to receive a filtered signal from at least a corresponding one of the plurality of filters;
- and
- a quality metric generator, operably coupled to receive at least a portion of the filtered signal, thereby producing at least one of a plurality of signal quality metrics.
8 more elements
An FM receiver configured to receive a desired signal at a frequency f1, the FM receiver comprising:
- a plurality of filters, including;
- a nominal filter with a center frequency f1 and a bandwidth B1;
- a higher frequency filter with a center frequency f2 and a bandwidth B2, wherein f2 is substantially equal to (f1+X2), wherein X2 is a variable frequency offset, and wherein B2 is substantially equal to B1;
- and
- a lower frequency filter with a center frequency f3 and a bandwidth B3, wherein f3 is substantially equal to (f1-X3), wherein X3 is a variable frequency offset, and wherein B3 is substantially equal to B1;
- wherein the center frequency and bandwidth for each of the plurality of filters is adjustable;
- means for performing a signal recovery of the desired signal on an output of each of the plurality of filters to obtain a plurality of recovered signals;
- and
- means for measuring the plurality of recovered signals to obtain a plurality of signal quality metrics, wherein each of the plurality of signal quality metrics corresponds to one of the plurality of filters.
6 more elements
An FM receiver configured to receive a desired signal at a frequency f1, the FM receiver comprising:
- a plurality of filters, including;
- a nominal filter with a center frequency f1 and a bandwidth B1;
- a larger bandwidth filter with a center frequency f4 and a bandwidth B4, wherein f4 is substantially equal to f1, wherein B4 is substantially equal to (B1+Y4), and wherein Y4 is a variable bandwidth offset;
- and
- a smaller bandwidth filter with a center frequency f5 and a bandwidth B5, wherein f5 is substantially equal to f1, wherein B5 is substantially equal to (B1-Y5), and wherein Y5 is a variable bandwidth offset;
- wherein the center frequency and bandwidth for each of the plurality of filters is adjustable;
- means for performing a signal recovery of the desired signal on an output of each of the plurality of filters to obtain a plurality of recovered signals;
- and
- means for measuring the plurality of recovered signals to obtain a plurality of signal quality metrics, wherein each of the plurality of signal quality metrics corresponds to one of the plurality of filters.
6 more elements
In an FM receiver configured to receive a desired signal at a frequency f1, the FM receiver including an encoder, a multiplexer, and a plurality of filtering elements that each apply a filter response to an inputted signal, the plurality of filtering elements including:
- a nominal filter response having a center frequency f1 and a bandwidth B1;
- a higher frequency filter response having a center frequency f2 and a bandwidth B2, wherein f2 is substantially equal to (f1+X2), wherein B2 is substantially equal to B1, and wherein X2 is based, at least in part, on a frequency offset sensitivity level for the FM receiver;
- a lower frequency filter response having a center frequency f3 and a bandwidth B3, wherein f3 is substantially equal to (f1-X3), wherein B3 is substantially equal to B1, and wherein X3 is based, at least in part, on a frequency offset sensitivity level for the FM receiver;
- a larger bandwidth filter response having a center frequency f4 and a bandwidth B4, wherein f4 is substantially equal to f1, wherein B4 is substantially equal to (B1+Y4), and Y4 is based, at least in part, on a channel bandwidth level for the FM receiver;
- a smaller bandwidth filter response having a center frequency f5 and a bandwidth B5, wherein f5 is substantially equal to f1, wherein B5 is substantially equal to (B1-Y5), and Y5 is based, at least in part, on a channel bandwidth level for the FM receiver;
- wherein the center frequency and bandwidth for each of the plurality of filtering elements are adjustable;
- a method for recovering the desired signal, the method comprising the steps of:
- A) inputting, to each of the plurality of filtering elements, the desired signal;
- B) performing a signal recovery of the desired signal on an output of each of the plurality of filtering elements to obtain a plurality of recovered signals;
- C) measuring the plurality of recovered signals to obtain a plurality of signal quality metrics for the desired signal;
- D) evaluating, at the encoder, each of the plurality of signal quality metrics for the desired signal to identify a recovered signal having a favorable signal quality metric;
- E) selecting, via the multiplexer, a corresponding one of the plurality of filtering elements, wherein a selected filtering element produces the recovered signal having the favorable signal quality metric;
- F) adjusting the center frequency and the bandwidth of at least some of the plurality of filtering elements, based on the center frequency and bandwidth of the selected filtering element;
- G) forming a usable output signal based on the selected filtering element;
- H) determining whether a communication remains in progress;
- and
- I) while the communication remains in progress, continuously repeating the step of inputting, to the plurality of filtering elements, the desired signal.
14 more elements
Dependencies are inferred from the claim text.