How To Minimize The Distortion (Linear/Nonlinear) In Pulse Modulation Signals?
Have you ever encountered such a situation: video calls suddenly lag, data transmission frequently malfunctions, and the device occasionally “goes on strike”? Don’t think this is just a minor problem. It’s very likely that the pulse modulation signal distortion is causing trouble! Distortion is like a “roadblock” on the signal transmission path, not only slowing down work efficiency but also potentially causing considerable economic losses. Today let’s talk together about how to solve this problem.
Signal Distortion: Why Is your device malfunctioning?
1. Troubles caused by distortion
Imagine that the message you sent was delivered to the other party by the signal “Courier”, but it turned out to be completely different content. Isn’t that frustrating? In practical work, signal distortion can lead to a soaring communication bit error rate and continuous data transmission errors. In the industrial field, distortion may throw automated equipment into disarray and even cause safety accidents. These problems not only waste time but may also cause additional costs such as equipment maintenance and data loss.
2. The “ideal state” of the signal you want
We all hope that pulse modulation signals can be as stable as Mount Tai: when communicating, the sound is clear and the picture is smooth. When the equipment is in operation, it accurately executes instructions without any errors. Only by solving the distortion problem can the maintenance cost be reduced, the risk of failure be decreased, and work and life be more worry-free.
Where Does Distortion Come From?
Distortion does not occur for no reason. It mainly falls into two categories: linear distortion and nonlinear distortion. Let’s take a look at how they “cause trouble”.
Linear Distortion
A channel is like a “highway” for transmitting signals, but this “road” is not always smooth. In linear distortion, channel “eccentricity” is a common cause. It shows signals of different frequencies differently. Some frequency signals run fast while others run slow, eventually leading to the “deformation and distortion” of the signal waveform, just like vehicles at different speeds driving on a bumpy road, with their formation disrupted. The “time difference” of group delay is like the members of a signal team having inconsistent paces, some fast and some slow. Over time, the entire signal “team” becomes chaotic, and the signal naturally becomes distorted.
Nonlinear Distortion
The components in the equipment also have their own “little quirks”. Take the “out-of-control” power amplifier as an example. It is like the engine of a car. When it is working normally, it has great power, but once it is overloaded, it will produce abnormal “noise” – nonlinear distortion. This kind of distortion will generate harmonics and intermodulation distortion, interfering with normal signals. Apart from power amplifiers, some other devices may also interfere with signals due to their own characteristics or unstable working conditions, leading to nonlinear distortion.
How To Solve Distortion In Pulse Modulation Signals
Having identified the root cause of the problem, let’s now see how to “cure it with a quick fix”.
Linear Distortion
To solve the problem of linear distortion, it is necessary to renovate the “path” of signal transmission. Channel “pavement leveling” can adopt time-domain and frequency-domain equalization techniques. Time-domain equalization is like using a “magic broom” to reorganize the deformed signal waveform neatly. Frequency-domain equalization is achieved by using a transverse filter to specifically “fix” the “eccentricity” problem of the channel for signals of different frequencies. By using the least mean square error algorithm, the signal transmission path becomes flat and smooth. In actual cases, after many communication systems adopted this method, the signal quality was significantly improved.
As for the “time difference” problem of group delay, to “adjust the time difference” of group delay, a group delay compensation network needs to be built. It is like a precise “clock regulator”, adjusting the “pace” of different frequency components in the signal to keep them consistent again, so that the signal can be transmitted in the correct form. During the adjustment process, we can evaluate the compensation effect through simple tests and continuously optimize until the signal returns to normal.
Nonlinear Distortion
In the face of nonlinear distortion, the key is to tame the devices. For power amplifiers that are prone to “getting out of control”, a “coolant” for power amplifiers is indispensable. Predistortion technology is like giving a “preventive injection” to a power amplifier in advance. Before the signal enters the amplifier, it first performs reverse processing on the signal to counteract the possible nonlinear distortion generated by the amplifier. Post-distortion technology is to correct the signal after it has been distorted by the amplifier. Feedforward technology is more like finding a “helper” for the amplifier, monitoring and correcting distortion in real time. These several technologies each have their own advantages and disadvantages. For instance, predistortion has a relatively low cost but limited accuracy, while feedforward technology works well but has a complex structure. We can make flexible choices based on actual needs.
In addition to power amplifiers, the “selection and optimization” of devices are also very important. When choosing devices, try to select those with low nonlinearity and stability, just as you should choose reliable ones when selecting employees. At the same time, reasonable layout of devices and design of circuits to avoid their “mutual interference” can also greatly reduce the generation of nonlinear distortion.
Let’s See How The Effect Is
After solving the distortion problem, how can one determine whether the effect is good or not? We can make use of some evaluation indicators, such as the error vector amplitude. It is like a “precise scale” to measure the difference between the actual value and the ideal value of the signal. The power ratio of adjacent channels can reflect the degree of interference of the signal to the surrounding channels. Through simple testing tools and methods, these data can be obtained. Then, based on the data results, see if further improvements are needed to enhance the signal quality to a higher level.
Summary
With the rapid development of technology, there are new “weapons” to solve signal distortion. Artificial intelligence technology is emerging. It can learn a large amount of signal data, intelligently identify distortion patterns, and automatically adjust parameters for compensation, just like having a “super intelligent assistant” to help. In the future, these new technologies may make signal distortion suppression simpler and more efficient.
If you have any special needs in solving the distortion problem of pulse modulation signals or encounter any difficult problems, please feel free to share at any time! We can discuss together and customize a customized solution for you to ensure smooth signal transmission!
