In the present invention, an all digital, multi channel RF transmitter is utilized for a parallel magnetic resonance imaging (MRI) device, MRI signal generation, modulation and amplification are employed entirely digitally in the proposed RF transmitter, which enables each transmit channel to be easily and individually reconfigured in both amplitude and phase. Individual channel control ensures a homogeneous magnetic field in the multi channel RF coil in MRI. Besides the homogeneous magnetic field generation, multi-frequency MRI signal generation is made easy by the present invention with very high frequency resolution. Multi-frequency enables faster image acquisition which reduces MRI operation time. Digital Weaver Single Side Band (SSB) modulation is also incorporated into the all digital transmitter to suppress unwanted bands of Double Side Band (DSB) MRI signals. The power amplifier in the MRI transmitter does not amplify the unwanted band so that SSB modulation leads to higher power efficiency.

A robust frequency drift tracking receiver. The received signal is translated to an intermediate frequency in the RF stage by a quadrature demodulator, and is then brought into the base band by a digital mixer made by a CORDIC. A base band processing stage allows for a synchronization of the receiver relative to the data frame, to estimate data and to output a counter-reaction signal to the CORDIC, obtained by integration of successive frequency corrections, with a predetermined step.

A method of transmitting a Physical Layer Convergence Procedure (PLCP) frame in a Very High Throughput (VHT) Wireless Local Area Network (WLAN) system includes generating a MAC Protocol Data Unit (MPDU) to be transmitted to a destination station (STA), generating a PLCP Protocol Data Unit (PPDU) by adding a PLCP header, including an L-SIG field containing control information for a legacy STA and a VHT-SIG field containing control information for a VHT STA, to the MPDU, and transmitting the PPDU to the destination STA. A constellation applied to some of Orthogonal Frequency Division Multiplex (OFDM) symbols of the VHT-SIG field is obtained by rotating a constellation applied to an OFDM symbol of the L-SIG field.

In the present invention, an all digital, multi channel RF transmitter is utilized for a parallel magnetic resonance imaging (MRI) device, MRI signal generation, modulation and amplification are employed entirely digitally in the proposed RF transmitter, which enables each transmit channel to be easily and individually reconfigured in both amplitude and phase. Individual channel control ensures a homogeneous magnetic field in the multi channel RF coil in MRI Besides the homogeneous magnetic field generation, multi-frequency MRI signal generation is made easy by the present invention with very high frequency resolution. Multi-frequency enables faster image acquisition which reduces MRI operation time. Digital Weaver Single Side Band (SSB) modulation is also incorporated into the all digital transmitter to suppress unwanted bands of Double Side Band (DSB) MRI signals. The power amplifier in the MRI transmitter does not amplify the unwanted band so that SSB modulation leads to higher power efficiency.

Systems and methods for efficient estimation of a most likely sequence are provided. In one embodiment, an electronic device includes most likely receiver circuitry that receives a convolutional encoded signal, generates a linearized representation of the convolutional encoded Gaussian minimum-shift keying signal, resulting in a pseudo-symbol stream, estimates a most likely sequence for the pseudo-symbol stream, and decodes the pseudo-symbol stream based upon the most likely sequence.

A method of transmitting a Physical Layer Convergence Procedure (PLCP) frame in a Very High Throughput (VHT) Wireless Local Area Network (WLAN) system includes generating a MAC Protocol Data Unit (MPDU) to be transmitted to a destination station (STA), generating a PLCP Protocol Data Unit (PPDU) by adding a PLCP header, including an L-SIG field containing control information for a legacy STA and a VHT-SIG field containing control information for a VHT STA, to the MPDU, and transmitting the PPDU to the destination STA. A constellation applied to some of Orthogonal Frequency Division Multiplex (OFDM) symbols of the VHT-SIG field is obtained by rotating a constellation applied to an OFDM symbol of the L-SIG field.

An apparatus for estimating carrier frequency offset includes an M.sup.th power circuit, a spectrum generating circuit, a peak frequency determining circuit and a frequency offset determining circuit. The M.sup.th power circuit performs an M.sup.th power calculation on an input signal to generate an M.sup.th power calculation result. The spectrum generating circuit generates an M.sup.th power spectrum according to the M.sup.th power calculation result. The peak frequency determining circuit determines a peak frequency corresponding to an amplitude peak from the M.sup.th power spectrum. The frequency offset determining circuit determines an estimated carrier frequency offset according to the peak frequency.

Techniques herein support enhanced multi-rate encoding and decoding of signals in multiple formats. In one embodiment, input data is received at a first device at one of a plurality of data rates. Encoder units are activated to produce streams of encoded input data. The encoder units are configured to operate at the same data rate. Differential encoding operations are performed to produce an encoded output stream. The encoded output stream is modulated for transmission to a second device. In another embodiment, a first device receives an encoded data stream that is transmitted from a second device. The modulated data stream includes encoded data at one of a plurality of data rates. Differential decoding is performed on the encoded data by activating one or more of a plurality of decoder units, where each of the plurality of decoder units is configured to operate at the same rate.

Techniques herein support enhanced multi-rate encoding and decoding of signals in multiple formats. In one embodiment, input data is received at a first device at one of a plurality of data rates. Encoder units are activated to produce streams of encoded input data. The encoder units are configured to operate at the same data rate. Differential encoding operations are performed to produce an encoded output stream. The encoded output stream is modulated for transmission to a second device. In another embodiment, a first device receives an encoded data stream that is transmitted from a second device. The modulated data stream includes encoded data at one of a plurality of data rates. Differential decoding is performed on the encoded data by activating one or more of a plurality of decoder units, where each of the plurality of decoder units is configured to operate at the same rate.

A robust frequency drift tracking receiver. The received signal is translated to an intermediate frequency in the RF stage by a quadrature demodulator, and is then brought into the base band by a digital mixer made by a CORDIC. A base band processing, stage allows for a synchronisation of the receiver relative to the data frame, to estimate data and to output a counter-reaction signal to the CORDIC, obtained by integration of successive frequency corrections with a predetermined step.