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Class Information
Number: 375/281
Name: Pulse or digital communications > Systems using alternating or pulsating current > Angle modulation > Phase shift keying > More than two phases > Quaternary
Description: Subject matter where the phases are 90 degrees apart.
Patents under this class:
| Patent Number |
Title Of Patent |
Date Issued |
| 7606321 |
System and method for simplifying analog processing in a transmitter incorporating a randomization circuit |
Oct. 20, 2009 |
| 7515645 |
Method for dividing the bit rate of QPSK signals into two or several subchannels |
Apr. 7, 2009 |
| 7426246 |
Dual layer signal processing in a layered modulation digital signal system |
Sep. 16, 2008 |
| 7412006 |
Method and apparatus for RF carrier feedthrough suppression |
Aug. 12, 2008 |
| 7409012 |
Modulator and signaling method |
Aug. 5, 2008 |
| 7356089 |
Phase offset spatial multiplexing |
Apr. 8, 2008 |
| 7319716 |
Transmitter image suppression in TDD transceivers |
Jan. 15, 2008 |
| RE39983 |
Carrier injecting waveform-based modulation scheme for reducing satellite transponder power requirements and earth terminal antenna size |
Jan. 1, 2008 |
| 7305042 |
T1 radio having coding gain adjustable for number of channels |
Dec. 4, 2007 |
| 7260159 |
Method and apparatus for providing higher order modulation that is backwards compatible with quaternary phase shift keying (QPSK) or offset quaternary phase shift keying (OQPSK) |
Aug. 21, 2007 |
| 7206417 |
Wireless digital transmission system for loudspeakers |
Apr. 17, 2007 |
| 7173981 |
Dual layer signal processing in a layered modulation digital signal system |
Feb. 6, 2007 |
| 7062228 |
Cellular communications system using baseband carrier injection and related methods |
Jun. 13, 2006 |
| 7057538 |
1/N-rate encoder circuit topology |
Jun. 6, 2006 |
| 7016425 |
Quasi-differential modulation/demodulation method for multi-amplitude digital modulated signals and OFDM system |
Mar. 21, 2006 |
| 6980774 |
Radio frequency integrated circuit |
Dec. 27, 2005 |
| 6973141 |
Flexible multimode QAM modulator |
Dec. 6, 2005 |
| 6836484 |
Wireless packet communication method and system for transmitting packets between base station and radio terminal station |
Dec. 28, 2004 |
| 6801564 |
Reverse link correlation filter in wireless communication systems |
Oct. 5, 2004 |
| 6763072 |
Method and apparatus for modulation and demodulation related to orthogonal frequency division multiplexing |
Jul. 13, 2004 |
| 6707860 |
DC offset correction for direct-conversion receiver |
Mar. 16, 2004 |
| 6690945 |
Method for suppressing transients using a pulse shaping look-up table |
Feb. 10, 2004 |
| 6683917 |
Base band signal processing circuit capable of improving both noise characteristic and distortion characteristic |
Jan. 27, 2004 |
| 6628727 |
Apparatus and method for performing .pi./4-DQPSK baseband modulation based on a signal mapping to be simplified |
Sep. 30, 2003 |
| 6621426 |
Method and apparatus for modulating a signal |
Sep. 16, 2003 |
| 6606357 |
Carrier injecting waveform-based modulation scheme for reducing satellite transponder power requirements and earth terminal antenna size |
Aug. 12, 2003 |
| 6594320 |
Orthogonal Frequency Division Multiplexed (OFDM) carrier acquisition method |
Jul. 15, 2003 |
| 6590945 |
Method and apparatus for frequency offset compensation |
Jul. 8, 2003 |
| 6496542 |
Digital communication system |
Dec. 17, 2002 |
| 6477153 |
Method and apparatus for using the sidelobe of a long range antenna for a short range communication link |
Nov. 5, 2002 |
| 6470056 |
Offset QPSK modulation analytic system |
Oct. 22, 2002 |
| 6462679 |
Method and apparatus for modulating a signal |
Oct. 8, 2002 |
| 6445745 |
Phase encoding methods for handling multiple phase modulated signals on a single channel |
Sep. 3, 2002 |
| 6445746 |
IS-136+ slot formation |
Sep. 3, 2002 |
| 6366622 |
Apparatus and method for wireless communications |
Apr. 2, 2002 |
| 6351503 |
Threshold extension block phase estimator for quasi-coherent communications systems |
Feb. 26, 2002 |
| 6332208 |
Data transmitting apparatus and data transmitting method |
Dec. 18, 2001 |
| 6301291 |
Pilot symbol assisted modulation and demodulation in wireless communication systems |
Oct. 9, 2001 |
| 6285721 |
Method for assisting simple synchronization to the carrier of a dispersed-energy QPSK signal |
Sep. 4, 2001 |
| 6243427 |
Multichannel radio frequency transmission system to deliver wideband digital data into independent sectorized service areas |
Jun. 5, 2001 |
| 6222878 |
Communication system with end-to-end quadrature balance control |
Apr. 24, 2001 |
| 6157679 |
Method of adding encryption/encoding element to the modulation/demodulation process |
Dec. 5, 2000 |
| 6125148 |
Method for demodulating information in a communication system that supports multiple modulation schemes |
Sep. 26, 2000 |
| 5999570 |
Transmission apparatus, sending apparatus, and receiving apparatus, and transmission method |
Dec. 7, 1999 |
| 5987068 |
Method and apparatus for enhanced communication capability while maintaining standard channel modulation compatibility |
Nov. 16, 1999 |
| 5950124 |
Cellular communication system with dynamically modified data transmission parameters |
Sep. 7, 1999 |
| 5933448 |
Automatic tuning of a radio transceiver |
Aug. 3, 1999 |
| 5930299 |
Digital modulator with compensation and method therefor |
Jul. 27, 1999 |
| 5847622 |
Quadrature phase shift keying modulating apparatus |
Dec. 8, 1998 |
| 5832044 |
Transmitter antenna diversity and fading-resistant modulation for wireless communication systems |
Nov. 3, 1998 |
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