We address the problem of blind carrier frequency-offset (CFO) estimation in quadrature amplitude modulation, phase-shift keying, and pulse amplitude modulation communications systems.We study the performance of a standard CFO estimate, which consists of first raising the received signal to the Mth power, where M is an integer depending on the type and size of the symbol constellation, and then applying the nonlinear least squares (NLLS) estimation approach. At low signal-to noise ratio (SNR), the NLLS method fails to provide an accurate CFO estimate because of the presence of outliers. In this letter, we derive an approximate closed-form expression for the outlier probability. This enables us to predict the mean-square error (MSE) on CFO estimation for all SNR values. For a given SNR, the new results also give insight into the minimum number of samples required in the CFO estimation procedure, in order to ensure that the MSE on estimation is not significantly affected by the outliers.
標簽： frequency-offset estimation quadrature amplitude
上傳時間： 2014-01-22
上傳用戶：牛布牛
In recent years large scientific interest has been devoted to joint data decoding and parameter estimation techniques. In this paper, iterative turbo decoding joint to channel frequency and phase estimation is proposed. The phase and frequency estimator is embedded into the structure of the turbo decoder itself, taking into consideration both turbo interleaving and puncturing. Results show that the proposed technique outperforms conventional approaches both in terms of detection capabilities and implementation complexity.
標簽： scientific parameter interest decoding
上傳時間： 2015-12-30
上傳用戶：894898248
This paper investigates the design of joint frequency offset and carrier phase estimation of a multi-frequency time division multiple access (MF-TDMA) demodulator that is applied to a digital video broadcasting—return channel system via satellite (DVB-RCS). The proposed joint estimation algorithm is based on the interpolation technique for two correlation values in the frequency and phase domains. This simple interpolation technique can significantly improve frequency and phase resolution capabilities of the proposed technique without increasing the number of the correlation values. In addition, the overall block diagram of a digital communications receiver for DVB-RCS is presented, which was designed using the proposed estimation algorithms. Index Terms—Carrier phase estimation, DVB-RCS, frequency offset estimation, interpolation, joint estimation, MF-TDMA.
標簽： investigates estimation frequency carrier
上傳時間： 2015-12-30
上傳用戶：ls530720646
16 relay output channels and 16 isolated digital input channels LED indicators to show activated relays Jumper selectable Form A/Form B-type relay output channel Output status read-back Keep relay output values when hot system reset High-voltage isolation on input channels(2,500 VDC) Hi ESD protection(2,00VDC) High over-voltage protection(70VDC) Wide input range(10~50VDC) Interrupt handling capability High-density DB-62 connector Board ID
標簽： channels indicators activated isolated
上傳時間： 2016-02-15
上傳用戶：dongbaobao
RFID標準：iso18000-6（英文版）。 Information technology — Radio-frequency identification for item management — Part 6: Parameters for air interface communications at 860 MHz to 960 MHz
標簽： Radio-frequency identification Information technology
上傳時間： 2014-01-17
上傳用戶：cainaifa
This project aim was to build wireless software modem for data communication between two computers using an acoustic interface in the voice frequency range (20Hz– 20,000Hz). The transmitting antenna is a speaker (frequency response of: 90Hz – 20,000Hz) and the receiving antenna is a microphone (frequency response of: 100Hz – 16,000Hz). The test files used as information files were text files. This goal was attained both in an incoherent scheme and in a coherent scheme. Build under Matlab code, our modem uses OFDM (orthogonal frequency division multiplexing) modulation, synchronization by LMS sequence, channel estimation (no equalizer) via pilot tones. The symbols are either PSK or ASK for a constellation size of 2 or 4. To optimize the probability of error, these symbols were mapped using Gray mapping. Report
標簽： communication computers software wireless
上傳時間： 2014-05-29
上傳用戶：wangdean1101
// // Histogram Sample // This sample shows how to use the Sample Grabber filter for video image processing. // Conceptual background: // A histogram is just a frequency count of every pixel value in the image. // There are various well-known mathematical operations that you can perform on an image // using histograms, to enhance the image, etc. // Histogram stretch (aka automatic gain control): // Stretches the image histogram to fill the entire range of values. This is a "point operation," // meaning each pixel is scaled to a new value, without examining the neighboring pixels. The // histogram stretch does not actually require you to calculate the full histogram. The scaling factor // is calculated from the minimum and maximum values in the image.
標簽： Sample Histogram Grabber sample
上傳時間： 2013-12-15
上傳用戶：ryb
：介紹了一種基于數字信號處理器（DSP）的移相調頻（Phase-Shifted and Frequency-Varied，PSFV）PWM控制 逆變電源，給出了主電路拓撲結構，分析了其控制原理并設計了其控制程序流程圖。新穎的PSFV 控制能夠實現輸出 電壓90％的調整率，輸出電流波動小于單純移相調功PWM方式，并在輕載時保持連續。功率開關器件零電壓零電流 通斷（Zero-Voltage-Zero-Current Switching，ZVZCS）軟開關的實現，有利于進一步提高開關頻率和降低開關損耗。采用 高性能的專用DSP 芯片TMS320F2812 實現了系統的數字控制，滿足了系統控制的靈活性和實時性，減小了系統的 體積和生產成本。仿真分析和實驗結果證明了此控制模式的可行性與合理性。
標簽： Frequency-Varied Phase-Shifted DSP and
上傳時間： 2013-12-04
上傳用戶：kristycreasy
Using LabVIEW 8.5 Language to control Tektronix AWG3102. This program can select output waveform, frequency and amplitude.
標簽： Tektronix Language waveform LabVIEW
上傳時間： 2016-05-17
上傳用戶：xlcky
Using LabVIEW to control Tektronix AWG2021 via GPIB. This program can select output waveform, frequency and amplitude.
標簽： Tektronix waveform LabVIEW control
上傳時間： 2014-10-13
上傳用戶：66666
