Abstract: Some power architectures require the power supply sequencer (or system manager) to controldownstream power MOSFETs to allow power to flow into branch circuits. This application note explains howsystem power sequencing and level Shifting can be accomplished using a low-voltage system manager
以89S52單片機(jī)和EP1C6Q240C8型FPGA為控制核心的多功能計(jì)數(shù)器，是由峰值檢波、A/D轉(zhuǎn)換、程控放大、比較整形、移相網(wǎng)絡(luò)部分組成,可實(shí)現(xiàn)測(cè)量正弦信號(hào)的頻率、周期和相位差的功能。多功能計(jì)數(shù)器采用等精度的測(cè)量方法，可實(shí)現(xiàn)頻率為1Hz～10MHz、幅度為0.01～5Vrms的正弦信號(hào)的精確測(cè)頻，以及頻率為10Hz～100kHz、幅度為0.5～5Vrms的正弦信號(hào)精確測(cè)相。液晶顯示器能夠?qū)崟r(shí)顯示當(dāng)前信號(hào)的頻率、周期和相位差。該多功能計(jì)數(shù)器精度高，界面友好，實(shí)用性強(qiáng)。
Abstract:
A multi-function counter，which uses89S52MCU and EP1C6Q240C8FPGA as a control core，consists of peak detector，A/D conversion，program-controlled amplification，compared shaping and phase-Shifting network part.The counter measures the frequency，period and phase of sinusoidal signal.With the equal precision method,the multi-function counter achieves the precise frequency measurement of the sinusoidal signal which its frequency is from1Hz to10MHz，its amplitude is from0.01Vrms to5Vrms，as well as the accurate phase measurement of the sinusoidal signal which its frequency is from10Hz to100kHz，its amplitude is from0.5Vrms to5Vrms.The LCD monitor real-time displays the frequency，period and phase difference of current signal.The multi-function counter features high precision，friendly interface，and strong practical.
介紹一種以MSP430單片機(jī)為基礎(chǔ)的智能頻率測(cè)量系統(tǒng)，采用硬件邏輯與軟件指令相結(jié)合的方式控制閘門，實(shí)現(xiàn)0 MHz~10 MHz范圍內(nèi)無檔切換的等精度測(cè)量。
Abstract:
An intelligent frequency measurement system based on MSP430 singlechip is introduced. The system uses a way that can combine hardware logic and software instructions to contronl the strobe ,and completes the functions of equal precision in the range of 0MHz~10MHz without Shifting
The PCA9517 is a CMOS integrated circuit that provides level Shifting between lowvoltage (down to 0.9 V) and higher voltage (2.7 V to 5.5 V) I2C-bus or SMBus applications.While retaining all the operating modes and features of the I2C-bus system during thelevel shifts, it also permits extension of the I2C-bus by providing bidirectional buffering forboth the data (SDA) and the clock (SCL) lines, thus enabling two buses of 400 pF. Usingthe PCA9517 enables the system designer to isolate two halves of a bus for both voltageand capacitance. The SDA and SCL pins are over voltage tolerant and arehigh-impedance when the PCA9517 is unpowered.
In today’s world of modular networking and telecommunications design, it is becomingincreasingly difficult to keep alignment with the many different and often changing interfaces,both inter-board and intra-board. Each manufacturer has their own spin on the way in whichdevices are connected. To satisfy the needs of our customers, we must be able to support alltheir interface requirements. For us to be able to make products for many customers, we mustadopt a modular approach to the design. This modularity is the one issue that drives the majorproblem of Shifting our bits from one modular interface to another.
These routines model tropospheric radiowave propagation over variable terrain and calculates propagation loss vs. height and range. Propagation loss is displayed in dB contours on a height vs. range plot. TPEM is based on the split-step Fourier PE method and was originally developed from an early PE model called PEPC, written by Fred Tappert. Propagation loss over variable terrain is modeled by Shifting the field an appropriate number of bin widths correspondc ing to the height of the ground. The field is determined using the smooth earth PE method.
A combined space鈥搕ime block coding (STBC) and eigen-space tracking
(EST) scheme in multiple-input-multiple-output systems is
proposed. It is proved that the STBC-EST is capable of Shifting
hardware complexity from the receiver to the transmitter without
any bit error rate (BER) performance loss. A computation efficient
EST algorithm is also proposed, which makes the STBC-EST affordable.
Simulation results show that the STBC-EST with a modest
feedback requirement results in a negligible BER performance loss
compared with a dual system configuration.
