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AV amplifier Knowledge entry – Features – Category articles: AV amplifier described in detail the role and reception of image and sound signals and other functions of knowledge. The following order by the purchase shopping network, available to you for reference.

AV amplifier s role and specific functions

Home theater systems AV amplifier is the control center. It needs to do many things, from the selection you want to listen to audio and video sources, up to amplify the sound signal to speaker-6/">drive speakers. Its role is very familiar with our stereo is very similar, but quite a number of differences. Stereo and AV amplifier can source in the different programs to choose between, you can control the playback volume, you can amplify the sound signal to drive speakers, however, AV amplifier has three unique features, is the stereo power amplifier does not have:

1), the surround sound signal to some form of decoding;

2), dealing with multi-channel (stereo amplifier rather than as only handle two-channel);

3), with the image signal input ports and output ports. The diagram shown. Another major role of the AV amplifier, is from the LD discs, VHS tapes, DSS signal or a DVD disc pick up the sound signal to decode. The so-called decoding equipment is picked up from the original sound source signal, converting them to left, right and left surround and right surround several analog audio signal. Finally, AV amplifier is also equipped with a 5-channel power amplifier inside, to the analog audio signal amplification, to drive home theater speakers.

AV amplifier brands, they are in performance, features and flexibility of use are not on the same, but in order to complete the same tasks, have specific functions such as these:

● receiving equipment from various sources (LD, VCR, DSS, DVD) picture and sound signals, select the desired signal, the images are sent to the monitor and speakers (this function is called the program source switching);

● According to the sound signal encoding format is Dolby Surround, Dolby Digital or DTS, the sound signal corresponding to the original surround sound decoder;

● pick up AM and FM radio signals;

● Adjust the volume;

● Adjust the initial setting system performance, for example, fine-tune the level of each channel;

● the bass delivery to the appropriate speakers and subwoofer (called bass management);

● the THX processing (when dealing with this circuit);

● After the 5-way signal amplifier to send drive left, right, left surround and right surround speakers.

Now, we have the program source selection, input and output port, surround sound decoding and amplification, etc. are described below:

Select the program source

In the home AV system, AV amplifier from a variety of programs to receive the first source of sound and picture signals. In this way, you can freely choose one program source, the signal it sent to the monitor speakers and images, enjoy. To do this, you only need to press or click on the amplifier panel a button on the remote control. At this time, there are often displayed on the panel, telling you what is currently selected program source; in some machines, it may be appropriate selection key next to the occurrence of light.

AV amplifier has many different brands and models, different models, they are able to connect the program source is not the same number. For example, some AV amplifier can be connected to two AV sources (sound and picture signals) and an audio signal source (eg CD player), then there is a group used to connect recorder (VCR) program source. And some AV amplifier, AV source can be connected to four, plus two sets of two recorders can be connected to the AV program source, etc.

Input and output ports to connect any one AV amplifier, equipped with only two groups fed Tone frequency signal input port; a CD player for the same connection, the other is for connection with the recorder. If you intend to ordinary phonograph (LP) connection, then, AV amplifiers should have a labeled \"PHONO\" input jack of the word.

AV amplifier all the audio input and output ports, use the RCA jack (commonly known as plum socket). Video port, RCA jack be useful, but also useful for the newer S-Video socket; the former is used to input composite video signal, which is used to input chrominance signal and luminance information has been separated from the video signal. Use S-video cable, DSS is only when the program source decoder box, DVD player and with S-VHS (High Definition Video Recorder) playback high-definition video (relatively rare), you will have a better effect. If the program source is the DSS receiver, DVD player or high-definition video recorder, then buy it with S-Video input and output sockets for AV receiver, will be able to obtain a higher quality picture. Of course, if the advantages of S-video connection to play out, you must also have the image monitor S-video input jack. In many AV amplifier, equipped with both composite video and S-video signal socket outlet available to you.

There are five groups of AV amplifier output terminal, used to power amplified audio signal transmission to the speakers. These five groups corresponding to the output of the left, middle, right, left surround and right surround channels 5. There is also a group of sixth output terminal, next to the printed \"SUBWOOFER OUT\" logo, designed to connect a subwoofer (you can not answer). The other five groups speaker output terminals are connected strong signal, this group of output terminals of the subwoofer output is low-level signals, but also requires a separate amplifier to be amplified. Most subwoofers have been equipped with an internal amplifier, it can be this low level subwoofer signal is fed to it directly.

AV amplifier s video output port, marked \"MONITOR OUT\" (the monitor connector). It is the role of the input video signal fed to the amplifier s image monitor. Amplifier regardless of what video source is selected, video signals are output from this port. This monitor is connected with the image port, which can be composite video signal output jack, it can be S-Video output jack; in some of the AV amplifier, you also installed the two sockets.

Installation of two video input and output sockets of the AV amplifier, the use must pay attention to a problem. If you put a program source with an S-video cable to connect your AV receiver, but the monitor is connected AV amplifier with image Shique using the composite video cable, then you will not see on the monitor image. In the program source and AV amplifier using S-Video connection between the AV amplifier and an image monitor must be used between the S-Video connection.

AV amplifier there are different types of the other three ports. Although they are used to input digital audio signals, but require different types of signals. This connection is to be careful, do not mistake. The first digital input port for receiving Dolby surround sound. This is a two-channel digital audio signal encoding, almost all of the LD disk are loaded with these signals, called PCM (pulse code modulation, a digital audio signal encoding) channel. Many laser disc player is equipped with a digital output terminal, if the laser disc player s digital output directly to the AV amplifier is connected to the digital input, this time due to the laser disc player around in the digital-analog conversion circuit and AV in The analog-digital conversion circuit, the resulting sound quality is better. In good quality AV receiver, most are in the digital domain Dolby Pro Logic decoding, that is, dealing with 1 and 0 signals. Digital connection, you can make the laser disc player and AV amplifier connected between the more direct. The other two digital audio signal input port, not to accept the PCM digital audio signal. One, next to the can labeled \"AC-3 RF\" word is used to input read from the LD drive the RF modulation, \"Dolby Digital\" signal. What kind of rest, without modulation is used to enter the \"Dolby Digital\" bit stream, such as the DVD player to output such a signal. In some AV receivers, the two \"Dolby Digital\" input ports into one, the machine can be modulated signal is sent, \"Dolby Digital\" or non-modulated signal, \"Dolby Digital\" signal, automatic conversion to complete the corresponding decoder. In some models, that enter the non-modulated \"Dolby Digital\" signal port can accept PCM signals, the machine will automatically signal in between these two forms of conversion.

It should be noted that the Dolby Digital surround sound signal RF modulation, is only a transitional measure, in order to facilitate the Dolby Digital surround sound recording in LD disk. However, the use of Dolby Digital surround sound audio and video sources (such as DVD and DSS), the output of all \"non-modulated\" or \"bit stream\" Dolby Digital surround sound signal.

Surround decoding

AV amplifier In addition to selecting the video source you want to enjoy, but also to decode the surround sound signal. Where almost all of the AV amplifier are installed Dolby Pro Logic decoding circuit; relatively new machine, you also have a separate channel Dolby Digital and DTS decoding. Typically, the universal AV receiver can only decode Dolby Pro Logic surround sound; in higher-priced products, the separation was equipped with digital surround sound format decoder. However, the low-cost receivers are now starting to have this decoder.

Dolby Pro Logic surround sound decoding signals, there are two ways: one is to decode the analog signal, a digital signal is decoded. If your AV amplifier is digitally Pro Logic decoder, a digital input jack, you can put player s digital output to your AV receiver in Pro Logic decoder is directly connected.

Power amplifier

AV amplifier has better amplifier to amplify the sound signal, the final drive home theater speakers. It is only with the two amplification stereo amplifier (left and right) of different, usually has 5 amplified channels (Left, Center, Right, Left Surround, Right Surround). Amplifier rated output power is the wattage per channel to represent, varies widely between different machines, low-only about 25 watts, high 150 watts.

Most of the AV amplifier, the power available for the front channels for the surround channels available than the larger. For example, a marked in the front three channels each provide 70 watts of power, AV amplifier, two surround channels to each one may provide only 35 watts. Reduced to two channels provide the power behind the possible reason is that home theater sound in the total output, two surround speakers emit sound is supposed to be released than the previous three speakers sound small. In addition, when using the Dolby Surround format, the surround sound box of the drive signal frequency response has been compressed, only from 100Hz to 7000Hz, 20Hz to 20,000 Hz, not from the entire audio bandwidth; surround speakers do not have to replay the bass, So you can use less power amplifier to drive.

Since Dolby Surround format products sold in the market has been dominant, manufacturers of power designed to surround the smaller, it seems nothing wrong. However, when the Dolby Digital and DTS surround sound formats since the advent of surround sound formats, because they are full-bandwidth surround channels, manufacturers have started a new product to the AV amplifier 5 channel all offer the same great power . For example, high-quality AV receiver including Dolby Digital decoding, surround speakers to provide their power, usually with the front three speakers to provide power as large.

In addition, some AV amplifier manufacturers in the design of the central channel when the power is also very stingy. They mistakenly believe that, through the central channel of the signal than the left or right channel by a small signal. So they reduce the power of the center channel amplifier. However, as consumers become more knowledgeable, these manufacturers were forced to change practices, has been provided for the front three channels of the same size, or roughly the same power. In fact, home theater systems, the role of the central channel of the largest, almost all of the dialogue to be replayed by it, in addition to some of the music and many sound effects.