WHAT IS PPM Encoder ?

About PPM Encoder

The PPM encoder allows to encode up to 8 PWM (pulse width modulated) signals into one PPM (pulse position modulation) signal.

The function of the PPM encoder is to encode the multi-channel PWM signal output by the receiver into a PPM composite signal output (up to 8 channels of PWM input) to connect the supported flight controllers in a single line.

PWM and PPM Introduction

PWM stands for Pulse Width Modulation and PPM stands for Pulse Position Modulation. PWM is a technique used to relay data in the form of a varying pulse width. In PPM (Pulse Position Modulation) the analogue sample values determine the position of a narrow pulse relative to the clocking time.

Advantages

The advantages of pulse position modulation include the following.

PPM has the most power efficiency as compared to other modulations.
This modulation has less stable amplitude noise interference.
This modulation separates the signal easily from a noisy signal.
It needs less power as compared to PAM.
Separation of signal & noise is extremely simple
It has constant transmitted power output.
It needs extremely less power as compared to PAM & PDM because of amplitude & short duration pulse.
Easy noise removal in this type of modulation.
Power utilization is also extremely low as compared to other modulations because of stable pulse amplitude & width.
PPM communicates only simple commands from a Tx to an Rx, so it is frequently used in lightweight applications because of its low system necessities.

Disadvantages

The disadvantages of pulse position modulation include the following.

PPM is very complex.
It needs more bandwidth for transmission as compared to PAM.
It is extremely sensitive to multi-pathway interference like echoing that can disturb a transmission by changing the difference in arrival times of every signal.
Synchronization is necessary between transmitter & receiver which is not feasible each time & we require a dedicated channel for it.
Special devices are required for this kind of modulation.

Applications

The applications of pulse position modulation include the following.

The PPM is mainly used in telecommunication systems & air traffic control systems.
This modulation is used in radio control, an optical communication system & military applications.
This technique is used in planes, remote-controlled cars, trains, etc.
PPM is used in noncoherent detection wherever a receiver does not require any Phase lock loop or PLL to track the carrier’s phase.
It is used in RF (radio frequency) communication.
It is also utilized in high-frequency, contactless smart cards, radio frequency ID tags, etc.

关于PPM编码器

PPM编码器允许将多达8个PWM(脉冲宽度调制)信号编码为一个PPM(脉冲位置调制)信号。

PPM编码器的功能是将接收机输出的多路PWM信号编码为PPM复合信号输出(最多8路PWM输入)，以单线连接所支持的飞行控制器。

PWM和PPM简介

PWM代表脉冲宽度调制，PPM代表脉冲位置调制。PWM是一种用于以变化脉冲宽度的形式传递数据的技术。在PPM(脉冲位置调制)中，模拟采样值确定相对于时钟时间的窄脉冲的位置。

优势

脉冲位置调制的优点包括以下方面。

与其他调制相比，PPM具有最高的电源效率。

这种调制具有较小的稳定振幅噪声干扰。

这种调制方式可以很容易地将信号从噪声信号中分离出来。

与PAM相比，它需要更少的能量。

信号和噪声的分离非常简单

它具有恒定的传输功率输出。

与PAM和PDM相比，它需要的功率非常少，因为它的振幅和脉冲持续时间短。

在这种类型的调制中容易去除噪声。

与其他调制相比，功率利用率也非常低，因为稳定的脉冲振幅和宽度。

PPM仅从Tx向Rx通信简单的命令，因此由于它对系统的需求较低，因此经常用于轻量级应用程序。

缺点

脉冲位置调制的缺点包括以下几个方面。

PPM非常复杂。

与PAM相比，它需要更多的带宽来传输。

它对回声等多路径干扰极其敏感，回声可以通过改变每个信号到达时间的差异来干扰传输。

发射机和接收机之间的同步是必要的，但不是每次都可行，我们需要一个专用的通道。

这种调制需要特殊的设备。

应用程序

脉冲位置调制的应用包括以下几个方面。

PPM主要用于电信系统和空中交通管制系统。

这种调制被用于无线电控制，光通信系统和军事应用。

这项技术用于飞机、遥控汽车、火车等。

PPM用于非相干检测，接收机不需要任何锁相环或锁相环来跟踪载波的相位。

它用于RF(射频)通信。

它还用于高频，非接触式智能卡，射频ID标签等。