What Are Pulse Signals?
This section provides an overview of pulse signals, which are used for various types of measurement and detection.
“Waves” of electrical signals—pulse signals
The “frequency” is the number of electrical signal vibrations that are repeated per unit of time, and “Hz (hertz)” is a unit that indicates the number of vibrations per second. The (square) waves of electrical signals that occur in such a short period of time and have a certain width are called “pulses” or “pulse signals.”
脉冲信号的分类
有各种类型的脉冲信号，它们根据其特征进行分类。下面介绍了分类脉冲的主要方法。
1. Classification by count
单个脉冲是指在发生事件时仅产生一次的脉冲，而连续脉冲是指在连续中重复产生的脉冲。单个脉冲的应用包括通道检测，而连续脉冲的应用包括电动机速度测量。
- 一种
- Successive pulses
- B.
- Single pulse
2. Classification by duration (width)
从一半点之间的时间间隔rising edge of a pulse and the peak to the half point between the peak and the falling edge is called the pulse duration. There are a wide variety of pulses—from those having an extremely short pulse duration like 0.1 μs to those having a duration of several seconds.
- 一种
- Pulse duration
3.间隔分类
This classification is based on the time interval between when repeated pulses are turned on and off. While the pulse duration refers to the period when pulses are turned on, this classification indicates the period when pulses are turned off. To increase the bit rate for optical communication or the like, it is necessary to put as many pulses as possible within a unit of time. In turn, this condition requires that the interval between output pulse signals be reduced.
- 一种
- Pulses on
- B.
- 脉冲
4. Classification by regularity
Pulses are classified according to whether they occur with a certain regularity or completely irregularly. Typical regular pulses include “serial communication signals,” whereas “human detection” is a typical example of irregular pulses.
脉冲的应用和调制方法
脉冲的应用主要被分类为“使用输入信号的测量”和“通过输出信号控制某些东西”。基本测量应用包括通过使用旋转编码器或类似装置来检测电动机速度，以基于脉冲信号显示和分析速度。另一方面，使用脉冲驾驶的典型系统包括各种类型的电动机，例如步进电机（脉冲电机）和伺服电动机。
Pulse modulation that controls motors
为了控制这些系统，在信息传输方面，它是“根据传输介质的特征调制”电信号“调制”电信号。特别地，根据脉冲变化传输和生成电信号的方法称为“脉冲调制”。使用的调制方法，特别是电机控制常见，是“脉冲宽度调制（PWM）”和“脉冲幅度调制（PAM）”。
脉冲宽度调制（PWM）
This method controls the current and voltage to pass depending on the pulse width (duration of continuous transmission) and the interval (time between pulses). The rate of “the period when pulses are on” in a certain period is called the “duty ratio (duty cycle),” and the optimal voltage is obtained by changing this rate. One feature of this method is its high efficiency because the voltage proportional to the pulse on duration can be obtained by shortening the on/off cycle. Another feature of this method is its fine control.
Pulse amplitude modulation (PAM)
Contrary to the pulse width modulation method, this method controls the current and voltage to pass depending on the pulse strength (amplitude). A pulse amplitude modulation inverter used for air-conditioning and similar systems changes the pulse voltage amplitude by controlling the voltage of the rectifier.
其他脉冲调制
脉冲代码调制（PCM）
该脉冲调制方法通过在特定周期中采样模拟信号并将其转换为二进制数（量化）来将输入模拟信号转换为数字信号（脉冲列车）。该方法也称为模数转换，用于传输模拟信号，例如声音，作为数字信号。其应用包括CD（CD-DAS），PCM录像机和蓝光（BDMV）。
Pulse density modulation (PDM)
This modulation generates waveforms on the basis of the pulse density within a time period divided into a specific width. This is one of the methods to convert analog signals such as sound and video to digital signals by replacing them with pulse trains. This method enables conversion with a higher sound quality than the PCM—a conventionally used method. This method is used for a new CD standard called “Super Audio CD (SACD).”
脉冲位置调制（PPM）
该脉冲调制方法将信号转换为具有一定宽度的时间脉冲相位差（位置）。该方法具有良好的噪声阻力，因为可以基于脉冲位置来确定脉冲信息。该方法通过在每个AC循环中更换脉冲时通过改变比率来控制电压，并用作应用于照明调整的“晶闸管驱动器”的控制脉冲，热源的温度调节等。
