30 results about "Carrier shift" patented technology

Disclosed herein is a signal processing apparatus including a processing block configured to perform a carrier shift amount detection process for detecting a carrier shift amount constituting a carrier error used for demodulating an orthogonal frequency division multiplexing signal known as the OFDM signal; and a correction block configured to correct the OFDM signal in accordance with the carrier shift amount. The OFDM signal includes a first preamble signal including subcarriers, and a second preamble signal including subcarriers of which the spacing is narrower than the spacing of the subcarriers included in the first preamble signal. The second preamble signal includes pilot signals which are known signals located at intervals of a predetermined number of subcarriers. The processing block detects the carrier shift amount using a correlation of the subcarriers included in one such second preamble signal.

A tuner selects a channel in a designated frequency band. An FFT circuit converts a received signal in the selected channel into a plurality of carrier signals. A carrier shift detection circuit calculates the correlation between the phase information of each carrier signal and reference phase information prepared in advance. If the correlation is larger than a given threshold, it is determined that an OFDM signal is present in the search target channel. A TMCC extraction circuit analyzes the TMCC of the received signal and determines whether or not digital broadcasts of the search target channel can be received.

The invention discloses a fast capturing method for a GNSS code. The fast capturing method mainly includes the steps that a code phase shift threshold and a carrier shift threshold are set in advance, a GNSS long code in a satellite signal and local pseudo code signals with different code phase shifts are subject to relevant processing, relevant results are subject to one-dimensional searching by a receiver, a correlation value is compared with the code phase shift threshold to acquire a code phase shift, and existence of a satellite is determined; then, one-dimensional carrier frequency searching is carried out, the correlation value is compared with the carrier shift threshold to acquire a carrier shift, and fast signal capturing is finished. The fast capturing method for the GNSS long code overcomes frequency shift accumulation brought by local crystal oscillators in the long code capturing process, and both sensitivity and speed are given consideration to finish fast long-code signal capturing without needing a large number of hardware resources.

A TMCC carrier is demodulated from a received OFDM signal having a TMCC carrier. A relative carrier position of the demodulated TMCC carrier is detected. A carrier shift amount is detected from the detected relative carrier position of the TMCC carrier and a normal TMCC carrier position. The received OFDM signal is corrected for the carrier frequency shift based on the detected carrier shift amount.

An optical homodyne communication system and method in which a side carrier is transmitted along with data bands in an optical data signal, and upon reception, the side carrier is boosted, shifted to the center of the data bands, and its polarization state is matched to the polarization state of the respective data bands to compensate for polarization mode dispersion during transmission. By shifting a boosted side carrier to the center of the data bands, and by simultaneously compensating for the effects of polarization mode dispersion, the provided system and method simulate the advantages of homodyne reception using a local oscillator. The deleterious effects of chromatic dispersion on the data signals within the data bands are also compensated for by applying a corrective function to the data signals which precisely counteracts the effects of chromatic dispersion.

The invention is concerned with the achieving project of the high dynamic mobile communication channel Doppler frequency-shift simulator, the project solves the Doppler frequency-shift simulating problem of the signal transmission at the high dynamic environment by the signal processing technology such as the time frequency domain transform, the interpolation fitting, the sampling.

Because data symbol is independent identically distributed random data symbol, if the sub-carrier is big enough, the phase difference to the number K sub-carrier caused by carrier shift and differential modulation is a random phase evenly distributed on (-pi,pi). If the value choice interval of carrier sequence number is supposed to be (-W,-W+1,...,-1,0,1,...,W-1,W), the carrier shift can be estimated by making a statistical average for all carriers. In order to improve estimation accuracy of theta z, a process for averaging multi continuing OFDM data symbols can be adopted.

The invention discloses an actual data packet restoration method based on 802.11ac. The aims of the invention are that incorrect signal state information feedback and identification of a low signal to noise ratio can be realized, CSI estimation errors are corrected, the signal to noise ratio is improved, an AP and all parallel transmission users of the AP are allowed to select a higher transmission rate at last, and the throughput of the network can also be improved. The adopted technical scheme is as follows: 1) the AP monitors CSI estimation containing errors after receiving a wrong data packet, and divides carriers into ''good'' carriers and ''bad'' carriers with an error rate as the standard, and the AP sends a training sequence to a plurality of users by using downlink beam forming to pass through the ''bad'' carriers; 2) based on the received training sequence, the users estimate the CSI again and report information to the AP to pass through the ''good'' carriers; 3) the AP judges factors causing the CSI errors, and then use different restoration mechanisms; and 4) CSI restoration includes CSI restoration of three factors of carrier shift, undersampled estimation and the low signal to noise ratio, and a composite factor of the three factors.

A refill module for use with a plunger assembly and having a housing (30), a syringe subassembly (70), a carrier (120) and at least one latching element (170). The syringe subassembly is shiftable within the housing from a retracted position to an injecting position at which its injection tip projects beyond the housing end. The carrier has a passageway in which a plunger of a plunger assembly is insertable for advancement of a piston (80) of the syringe subassembly. The syringe subassembly is engagable by the carrier to be moved from its injecting position to a point at which the injection tip is retracted within the housing when the carrier shifts from a first axial position to a second axial position. The at least one latching element is shiftable relative to the carrier from a retracted arrangement to a latching arrangement such that a latch surface of the latching element restricts a size of the passageway to prevent plunger withdrawal. The carrier is liftable within the housing to retract the injection tip into the housing when the at least one plunger is retracted and a latch abutment surface of that plunger engages the latch surface. When the carrier reaches the second axial position, the at least one latching element is shiftable to move the latch surface clear of the latch abutment surface to allow withdrawal of the at least one plunger from the passageway without further lifting of the carrier.

A node and an access node and methods therein for handling random access are disclosed. A method in a node for random access in a wireless network comprises, determining a set of sub-carrier shifts, wherein each sub-carrier shift indicates a shift with respect to a starting position in frequency domain for transmitting a random access preamble. The method further comprises selecting a sub-carriershift from the set of sub-carrier shifts. The method further comprises transmitting a random access preamble to an access node, wherein the random access preamble is transmitted according to the selected sub-carrier shift.

The invention discloses a mounting frame for carrying an external unit of an air conditioner, belonging to the technical field of air conditioner installation, comprising a bottom plate, sliding rails located on the left and right sides of the bottom plate parallel to each other, a carrier plate located above the bottom plate, and two sliding rails fixed at the lower end of the carrier plate. shaft; the section of the slide rail is C-shaped, and the C-shaped openings of the two slide rails are opposite; the two shift shafts are perpendicular to the slide rails, and the two ends of the shift shaft extend into the slide rails on both sides; the two shift shafts Both ends are fixed with a rectangular block corresponding to the slide rail, and the surface of the rectangular block is provided with a plurality of steel balls that are respectively in contact with the inner walls of the slide rail opening; the middle of the front and rear ends of the bottom plate is provided with a limit block, and two shifting shafts The middle part of the lower end of each is provided with a positioning block corresponding to the limiting block; the top surface of the limiting block is higher than the bottom surface of the positioning block. Easy maintenance, stable and reliable installation, labor-saving operation, reducing labor consumption of the operator.

The invention discloses a dual-pilot frequency carrier resetting device for aviation wireless communication. The carrier resetting device comprises a multistage convolution cascading filtering module, a rough carrier resetting module and a fine carrier resetting module. The multistage convolution cascading filtering module performs multistage convolution cascading filtering, and obtains upper sideband pilot frequency information, lower sideband pilot frequency information and modulation data information containing pilot frequency information according to rough carrier resetting information provided by the rough carrier resetting module. The rough carrier resetting module performs frequency discrimination and analysis for the upper sideband pilot frequency information and the lower sideband pilot frequency information provided by the multistage convolution cascading filtering module, controls completion of rough carrier shift compensation of standard complex baseband signals and outputs the rough carrier shift compensation to the multistage convolution cascading filtering module. The fine carrier resetting module performs phase discrimination and analysis on the upper sideband pilot frequency information and the lower sideband pilot frequency information provided by the multistage convolution cascading filtering module, and completes fine carrier shift compensation for modulation data information provided by the multistage convolution cascading filtering module according to the results of the frequency discrimination and the analysis.

The invention discloses a carrier synchronization realizing method under a physical layer simulation mode of a DMR (Digital Mobile Radio) communication system. In the method, a DSP (Digital Signal Processor) reads an I value and a Q value from an intermediate-frequency digitalization processing chip; the DSP calculates carrier shift according to the I value and the Q value; the DSP adjusts a phaselocked loop parameter according to the carrier shift; and a phaselocked loop locks phases to achieve carrier synchronization. The invention can be applied to the carrier synchronization under the physical layer simulation mode of the DMR communication system, and can be further expanded to the field of communication products under all CPFSK (Continuous Phase Frequency Shift Keying) modulation modes. By adopting the invention, the problem of carrier synchronization tracking frequency offset can be solved, fast and accurate synchronization is realized on a DSP platform, and carrier synchronization can be fast and precisely realized within 6ms (which is relative to the locking time of a used phaselocked loop chip), wherein the synchronization precision is 16.02HZ.