DFT(Discrete Fourier Transformation)是數字信號分析與處理如圖形、語音及圖像等領域的重要變換工具，直接計算DFT的計算量與變換區間長度N的平方成正比。當N較大時，因計算量太大，直接用DFT算法進行譜分析和信號的實時處理是不切實際的。快速傅立葉變換(Fast Fourier Transformation，簡稱FFT)使DFT運算效率提高1～2個數量級。其原因是當N較大時，對DFT進行了基4和基2分解運算。FFT算法除了必需的數據存儲器ram和旋轉因子rom外，仍需較復雜的運算和控制電路單元，即使現在,實現長點數的FFT仍然是很困難。本文提出的FFT實現算法是基于FPGA之上的，算法完成對一個序列的FFT計算，完全由脈沖觸發，外部只輸入一脈沖頭和輸入數據，便可以得到該脈沖頭作為起始標志的N點FFT輸出結果。由于使用了雙ram，該算法是流型(Pipelined)的，可以連續計算N點復數輸入FFT，即輸入可以是分段N點連續復數數據流。采用DIF(Decimation In Frequency)-FFT和DIT(Decimation In Time)-FFT對于算法本身來說是無關緊要的，因為兩種情況下只是存儲器的讀寫地址有所變動而已，不影響算法的結構和流程，也不會對算法復雜度有何影響。
This example demonstrates how the C8051F06x SMBus interface can communicate
// with a 256 byte I2C Serial EEPROM (Microchip 24LC02B).
// - Interrupt-driven SMBus implementation
// - Only master states defined (no slave or arbitration)
// - Timer4 used by SMBus for SCL low timeout detection
// - SCL frequency defined by <SMB_FREQUENCY> constant
//
// 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.
Squaring circuits are an important building block for impulse-radio UWB non-coherent receivers. This work proposes a squarer, based on the quadratic law of saturated transistors. Such a circuit has already been proposed for lower frequency applications, therefore this work focuses on the extension to ultra wide bandwidth, with particular care to the consequences related to the deviation from the ideal quadratic law of 0.18μm CMOS transistors.
This paper presents the key circuits of a 1MHz bandwidth, 750kb/s GMSK transmitter. The fractional-N synthesizer forming the basis of the transmitter uses a combined phasefrequency
detector (PFD) and digital-to-analog converter (DAC) circuit element to obtain >28dB high frequency noise reduction when compared to classicalfrequency synthesis.
This manual describes Freescale’s IEEE™ 802.15.4 Standard compliant MAC/PHY software. The Freescale 802.15.4 MAC/PHY software is designed for use with the Freescale MC1319x and MC1320x, family of short range, low power, 2.4 GHz Industrial, Scientific, and Medical (ISM) band transceivers, designed for use with the HCS08 Family of MCUs. The MAC/PHY software also works with the MC1321x family of short range, low power, 2.4 GHz ISM band transceivers that incorporate a low power 2.4 GHz radio frequency transceiver and an 8-bit microcontroller into a single LGA package.
Throughout this manual, the term transceiver refers to either the MC1319x, MC1320x, or the internal counterpart inside the MC1321x System in a Package (SiP).
JLAB is a set of Matlab functions I have written or co-written over the past fifteen years for the purpose of analyzing data. It consists of four hundred m-files spanning thirty thousand lines of code. JLAB includes functions ranging in complexity from one-line aliases to high-level algorithms for certain specialized tasks. These have been collected together and made publicly available for you to use, modify, and --- subject to certain very reasonable constraints --- to redistribute.
Some of the highlights are: a suite of functions for the rapid manipulation of multi-component, potentially multi-dimensional datasets a systematic way of dealing with datasets having components of non-uniform length tools for fine-tuning figures using compact, straightforward statements and specialized functions for spectral and time / frequency analysis, including advanced wavelet algorithms developed by myself and collaborators.
This program is used to measure the temperature sensor on an F330
device. It uses 1-point calibration and stores the offset value
in FLASH memory. The program outputs temperature values in 100ths
of a degree Celsius with UART.
