Resources Contact Us Home
Browse by: INVENTOR PATENT HOLDER PATENT NUMBER DATE
 
 
Digital FSK demodulator










Image Number 14 for United States Patent #4825452.

The present invention provides a digital frequency shift keying (FSK) demodulator circuit which receives a hard-limited FSK input signal and recovers the modulating baseband signal at 300 baud or less. The FSK demodulator includes a digital phase locked loop demodulator section which receives the FSK input signal and generates a pulse width modulated output the frequency of which is a function of the input signal frequency. The output of the PLL demodulator section is provided to a quantizer which generates a set of parallel numbers. A translating means, for example a code linearizer, converts the parallel numbers into corresponding parallel outputs which are representative of the frequency of the FSK input signal. The parallel outputs are processed by a digital filter which emulates a second-order, low-pass filter. The filter processes the parallel outputs utilizing pulse density modulation. A deglitcher removes noise from the filter output to provide the demodulated data output.








 
 
  Recently Added Patents
Selecting one of a plurality of print modes based on pixel coverage of a document
Detachably integrated battery charger for mobile cell phones and like devices
Cucumber plants with a compact growing habit
Digital rights management for media streams
Drive and startup for a switched capacitor divider
Methods and systems for automated backups and recovery on multi-os platforms using controller-based snapshots
Authenticating and off-loading IPTV operations from mobile devices to fixed rendering viewing devices
  Randomly Featured Patents
Hydrogen storage alloy and hydride electrodes having C15 crystal structure
Pedicure slipper
Semiconductor device having at least a pixel unit and a driver circuit unit over a same substrate
Color cathode-ray tube (CRT) and method of producing the same
Device method and computer program product for sharing web feeds
Helmet bracket
Secure data entry device
Flexible sheating for connecting corridors
Anti-runout device and conveyor apparatus
Garment carrying electronic devices