A new cable fault location method based on
wavelet reconstruction is proposed. In this method the
difference between the currents of faulty phase and sound
phase under the high voltage Pulse excitation is used as the
measured signal and is decomposed in multi-scale by wavelet
transform, then reconstructed in single scale. Comparing with
traditional fault location method by travelling wave, the
presented method will not be interfered by the reflected wave
from the branch joint of cables or from other positions where
the impedances are not matched and not be influenced by fault
types, otherwise, the reflected waves can be recognized even
the faulty position is near to the measuring terminal, at the
same time, the influence of the wave speed uncertainty can be
reduced. The correctness of the proposed method is proved by
simulation results.
A digital fi‘equeney meter designed with FPGA development software Q-~us 11 is introduced．The 1 Hz—l MHz input measured Pulse signals of the digital ii‘equency meter can be used for measuring frequency，period，Pulse width and duty ratio，etc．The test results stably display O71 3 seven—segment numeric tubes，and the measuring ranges may be switched over automatically．The measuring error is equal to or less than 0．1％．
This example demonstrates the use of the ADC block and PWM blocks. The generated DSP code produces the Pulse waveform whose duty cycle is changing as the voltage applied to ADC input changes. The waveform period is kept constant.
The PWM_1 project is a simple program for the STM32F103RBT6
using Keil MCBSTM32 Evaluation Board and demonstrating
the use of PWM (Pulse Width Modulation) with Timer TIM4.
This m file simulates a differential phase shift keyed (DPSK) ultra wide bandwidth(UWB) system using a fifth derivative waveform equation of a Gaussian Pulse.
Modify the Gray-coded modulation example (COMMDOC_GRAY)
so that it uses a pair of square root raised cosine filters
to perform Pulse shaping and matched filtering at the
transmitter and receiver, respectively.
Tiny Planet is small device connected to a GSM cell phone. When the mobile receives a predefined SMS (text message), like "Activate burglar alarm" or "Start backup pump", the circuit automatically recognizes it as a command, and switches the output port accordingly. Besides switching the port on or off, the user can Pulse it for a short period (e.g. 鈥淩eboot remote server鈥?.
