With the development of electronic technology and chip manufacturing technology, a new type of power amplifier has matured into the field of professional audio and has become a powerful challenger for traditional simulation.
This paper introduces the principle and composition of the digital amplifier, then compares the digital amplifier with the simulation amplifier, and expects everyone to make a reasonable choice in the work.
As the name implies, digital amplification is the use of digital technology. The author summarizes the following six aspects, and adopts digital technology, which is the highlight of digital amplifier.
1. Digital switching power supply is used in the power supply.
Digital switching power supply is a digital stabilized power supply with PWM (pulse width modulation) technology. Its principle is to simulate sine wave voltage after rectifying filtering the pulsating dc, after the switch tube control, forming a series of different changes of pulse width, through the pulse transformer coupling transmission to subprime, forming a set or more sets of pulse voltage output, after filtering, the dc output work need.
Because the pulse wave is modulated and the frequency is high, the pulse transformer is small in volume and high in transmission efficiency. With the change of pulse wave duty ratio, different voltage values can be obtained.
Due to the PWM technology is very mature, components reliability is higher, so its application is very broad, such as color TV sets, all kinds of electronic equipment are used, compared with the traditional tandem manostat, have to adapt to the wide input voltage (90 ~ 250 v), high efficiency (90%), light weight, small volume (save ordinary power transformer), high reliability (save by load current of the power adjusting pipe), and many other advantages, is the first selection of all kinds of power converter.
2. A/D and D/A converters are adopted.
The so-called A/D and D/A are analog to digital and digital simulation. The input and output of the digital amplifier is usually the analog signal, and the digital amplifier is all digital signals, so the input and output must be converted by A/D and D/A.
3. The amplifier generally increases DSP.
DSP digital signal processing, because many DSP chip, function contains various effects: delay, pressure limit, balanced, filtering, etc, if you need to add, greatly enriched the effect and function of the power amplifier, and due to the is digital signal processing, no distortion, no background noise, large dynamic range, power amplifier quality is high, the scale can be easily done.
4. D-type amplifier circuit is adopted in the final stage.
Digital power amplifier of the large signal processing type D amplifier circuit is adopted, the equivalent of PWM circuit, the conversion efficiency is very high (> 90%), the requirement to the power amplifier tube: quantity, such as power, voltage is reduced greatly, the modulation frequency is five times as many as 20 KHZ audio, 100 KHZ, the requirements for the work frequency of the power amplifier tube is a piece of cake.
5. Easy to add network functions.
As audio network technology matures, multichannel audio signal transmission through Ethernet, control become very convenient, digital power amplifier generally increased access to the RJ45 Ethernet interface, thus bring network audio amplification, monitoring, management convenience.
6. Use PC to set the digital amplifier and monitor the working status.
Due to the application of digital technology and the popularization of computer application, it is easy to use the management software to realize remote control, monitoring and other functions.