Abstract: An automatic gain control method and system for use in signal processing of OFDM symbols at a receiver. Two stages of coarse and fine automatic gain control are implemented that adjust different gains in an analog RF processing stage of the receiver. Gain of a low noise amplifier and a mixer are adjusted during a first and coarse automatic gain control stage based on feedback from a digital baseband stage. During a subsequent fine gain control period, the gain of a programmable gain amplifier is adjusted separately for each frequency band used by the OFDM symbols based on a histogram bin that counts the number of output samples of an analog to digital converter whose magnitude falls within certain ranges. Coarse and fine gains are updated after each OFDM symbol.

Abstract: A receiver including a channel estimation function in which an initial channel estimate is filtered to increase receiver operation, particularly when the receiver may only have a limited number of channel estimation symbols with which to form the channel estimate. In some embodiments the filtering is performed by transforming the initial channel estimate to the time domain, zeroing some of the samples to filter the time domain channel estimate, and transforming the filtered time domain channel estimate to the frequency domain for use in channel compensation.

Abstract: Systems and methods for packet detection for frequency hopping networks. Multiple receiver chains are set to different frequencies to check for packets at the different frequencies, at least until receipt of a preamble sequence in a packet is received. After detection of a packet at least some of the receiver chains are used to process received signals according to a frequency hopping pattern.

Abstract: Pairs of parallel Viterbi decoders use windowed block data for decoding data at rates above 320 Mbps. Memory banks of the deinterleavers feeding the decoders operate such that some are receiving data while others are sending data to the decoders. Parallel input streams to every pair of decoders overlap for several traceback lengths of the decoder causing data input to a first decoder at the end of an input stream to be the same as the data input to a second decoder of the same pair at the beginning of an input stream. Then, the first decoder is able to post-synchronize its path metric with the second decoder and the second decoder is able to pre-synchronize its path metric with the first. Either, the deinterleaver data length is an integer multiple of the traceback length or the data input to only the first block of the first interleaver is padded.

Abstract: Frame synchronization methods and systems suited for packet communications systems, and particularly time frequency hopping packet communication systems, are disclosed. Frame synchronization is performed by performing a first correlation on information of received symbols and performing a second correlation on results of the first correlation. In systems with repeating synchronization information modulated by a cover sequence, the results of the second correlation may be used to determine symbol numbering of symbols in a packet.

Abstract: The invention provides a rotary joint device and a support frame and a camera apparatus therewith. The rotary joint device includes a first rotary member, a second rotary member, and a positioning device. The first rotary member includes a first positioning recess space and a second positioning recess space. The second rotary member is pivotally engaged to the first rotary member and includes a hole. The positioning device includes a body, a resilient, and a positioning part. The body includes an accommodating space. The resilient is accommodated in the accommodating space and is connected to the body and the positioning part respectively. The body is disposed in the hole and is connected to the second rotary member. The positioning part is urged against the first rotary member and is accommodated in the first positioning recess space or the second positioning recess space.

Abstract: An iodonium compound of formula (I): where RAR1 is a C5-6 aryl group, bearing at least one substituent selected from formyl, thionoacyl, acylamidocarboxy, thionoester, azo, C2-20 alkenyl, C2-20 alkynyl, and (CH2)nRC, where RC is selected from ether, amino, azo and thioether; RAR2 is a C5-10 aryl group, optionally substituted by one or more groups selected from C1-12 alkyl, C5-12 aryl, C3-12 heterocyclyl, ether, thioether, nitro, cyano and halo, and may be linked to a solid support or fluorous tag; and X is a counteranion.

Abstract: The present invention provides a process comprising substitution of an acceptor molecule comprising a group —XC(O)— wherein X is O, S or NR8, where R8 is C1-6 alkyl, C6-12 aryl or hydrogen, with a nucleophile, wherein the acceptor molecule is cyclised such that said nucleophilic substitution at —XC(O)— occurs without racemisation. This process has particular application for the production of a peptide by extension from the activated carboxy-terminus of an acyl amino acid residue without epimerisation.

Abstract: A receiver including a channel estimation function in which an initial channel estimate is filtered to increase receiver operation, particularly when the receiver may only have a limited number of channel estimation symbols with which to form the channel estimate. In some embodiments the filtering is performed by transforming the initial channel estimate to the time domain, zeroing some of the samples to filter the time domain channel estimate, and transforming the filtered time domain channel estimate to the frequency domain for use in channel compensation.

Abstract: Frame synchronization methods and systems suited for packet communications systems, and particularly time frequency hopping packet communication systems, are disclosed. Frame synchronization is performed by performing a first correlation on information of received symbols and performing a second correlation on results of the first correlation. In systems with repeating synchronization information modulated by a cover sequence, the results of the second correlation may be used to determine symbol numbering of symbols in a packet.

Abstract: Pairs of parallel Viterbi decoders use windowed block data for decoding data at rates above 320 Mbps. Memory banks of the deinterleavers feeding the decoders operate such that some are receiving data while others are sending data to the decoders. Parallel input streams to every pair of decoders overlap for several traceback lengths of the decoder causing data input to a first decoder at the end of an input stream to be the same as the data input to a second decoder of the same pair at the beginning of an input stream. Then, the first decoder is able to post-synchronize its path metric with the second decoder and the second decoder is able to pre-synchronize its path metric with the first. Either, the deinterleaver data length is an integer multiple of the traceback length or the data input to only the first block of the first interleaver is padded.

Abstract: A method and system for removing frequencies interfering with a UWB OFDM receiver from transmission frequencies of the UWB communication. A sensing mechanism is added to the receiver that develops an energy histogram for the frequencies in a received signal and develops a tone mask for masking the interfering frequencies. The tone mask is applied after a mapping stage in the transmitter of the UWB communication and removes the interfering frequencies from the transmitted signal. Various criteria based on energy averaging are used to identify and null and remove the interfering frequencies.

Abstract: An automatic gain control method and system for use in signal processing of OFDM symbols at a receiver. Two stages of coarse and fine automatic gain control are implemented that adjust different gains in an analog RF processing stage of the receiver. Gain of a low noise amplifier and a mixer are adjusted during a first and coarse automatic gain control stage based on feedback from a digital baseband stage. During a subsequent fine gain control period, the gain of a programmable gain amplifier is adjusted separately for each frequency band used by the OFDM symbols based on a histogram bin that counts the number of output samples of an analog to digital converter whose magnitude falls within certain ranges. Coarse and fine gains are updated after each OFDM symbol.

Abstract: An apparatus for and a method of performing packet detection in a receiver is provided. The apparatus is configured to determine a measure of a correlation between information of one or more received symbols and synchronization information. The apparatus is also configured to determine a measure of an energy value of one or more of the received symbols. The apparatus is also configured to determine if a packet has been detected based on the measure of the correlation and the measure of the energy value of the one or more received symbols.

Abstract: Architectures for ultrawideband transmitters and receivers including parallel processing chains. Some embodiments include a two byte interface with a MAC, and some embodiments include mappers mapping I-channel and Q-channel information from separate encoders.

Abstract: A direct conversion ultrawideband transceiver employing three phase locked loops (PLLs). The PLLs are preferably fixed-frequency PLLs that operate continuously, at different frequencies, with a selected frequency determined by selecting the output of one of the three PLLs. The use of three PLLs is suitable for use in a communication system employing frequency hopping across three bands or sub-bands.

Abstract: Systems and methods for packet detection for frequency hopping networks. Multiple receiver chains are set to different frequencies to check for packets at the different frequencies, at least until receipt of a preamble sequence in a packet is received. After detection of a packet at least some of the receiver chains are used to process received signals according to a frequency hopping pattern.

Abstract: Methods and systems using information derived during a signaling period of a scheduling-based Medium Access Control protocol to adjust operation effective during data transmission periods. For example, channel estimation and transmission power adjustments are made based on indications provided by received signals.