Digital demodulator using boxcar filters and boxcar filter sections
This invention relates in general to electronic circuits and more specifically to a digital demodulator and a communication device having said digital demodulator. A digital demodulator () includes a differentiate and cross multiply stage () and a plurality of filter/decimator stages (and and ) that...
Saved in:
| Main Authors | , , |
|---|---|
| Format | Patent |
| Language | English |
| Published |
27.08.2002
|
| Online Access | Get full text |
Cover
Loading…
| Summary: | This invention relates in general to electronic circuits and more specifically to a digital demodulator and a communication device having said digital demodulator.
A digital demodulator () includes a differentiate and cross multiply stage () and a plurality of filter/decimator stages (and and ) that accept both multiple baud rates and multiple modulation deviation frequencies, and that provide a common frequency data stream at their respective outputs. One of said filter/decimator stages is coupled to a primary filter () which is followed by a box filter (). The box filter () improves the overall filter response and provides notches at a specified frequency (e.g., 4800 Hz) and its harmonics. Demodulator () provides improved sensitivity without the need for any circuit trimming. The filter stages (e.g., and ) used in demodulator () have been optimized to eliminate the need for costly multipliers. |
|---|