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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:
1 2 3

Patent Number Title Of Patent Date Issued
8548105 Joint time-frequency automatic gain control for wireless communication Oct. 1, 2013
8467461 Data transfer system Jun. 18, 2013
8385457 Methods and systems to compensate IQ imbalance in wideband zero-if tuners Feb. 26, 2013
8315586 Signal receiving device and signal receiving method using same, and signal supplying unit and signal supplying method using same Nov. 20, 2012
8199864 Quadrature phase shift keying demodulator of digital broadcast reception system and demodulation method thereof Jun. 12, 2012
8199847 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) Jun. 12, 2012
8189708 System and method for accurate downlink power control of composite QPSK modulated signals May. 29, 2012
8190163 Methods and apparatus of enhanced coding in multi-user communication systems May. 29, 2012
8155250 Receiver with frequency offset compensation for M-state phase modulation Apr. 10, 2012
8139688 Differential receiver with frequency offset compensation Mar. 20, 2012
8121214 Local oscillator with non-harmonic ratio between oscillator and RF frequencies using XOR operation Feb. 21, 2012
8065586 Radio communication apparatus Nov. 22, 2011
8050368 Nonlinear adaptive phase domain equalization for multilevel phase coded demodulators Nov. 1, 2011
8050350 Receiver I-Q balance calibration Nov. 1, 2011
7995678 System and method for communicating data using weighted bit soft decisions for differentially encoded phase shift keying Aug. 9, 2011
7983235 High speed overlay mode for burst data and real time streaming (audio) applications Jul. 19, 2011
7953033 Method of signalling, a communication system and a communication equipment May. 31, 2011
7940639 Interference suppressing OFDM system for wireless communications May. 10, 2011
7933354 Encoding and decoding architecture and method for pipelining encoded data or pipelining with a look-ahead strategy Apr. 26, 2011
7869533 Communication system and method for receiving high priority and low priority signals Jan. 11, 2011
7844011 Apparatus and method for improving symbol error rate performance of M-ary phase shift keying system having quadrature error Nov. 30, 2010
7809083 Differential receiver with frequency offset compensation Oct. 5, 2010
7769096 QM-CPM modems with higher order signaling Aug. 3, 2010
7646825 Impulse generating device, communication device, and a computer-readable recording medium recording an impulse control program thereon Jan. 12, 2010
7630290 Interference suppressing OFDM system for wireless communications Dec. 8, 2009
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

1 2 3

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