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PCM audio, commonly known as pulse modulation, is a way of representing sampled analog signals in digital form. It’s the most common type of digital audio found in computers, CDs, digital telephony, and other digital audio devices. The amplitude of the analog signal is sampled at even intervals in a PCM stream, and each sample is quantized to the nearest value in a range of digital steps.

Why PCM is important to your A/V installation?

The technique of transforming an analog audio signal (represented by a waveform) into a digital audio signal (represented by 1s and 0s) without compression is known as PCM (Pulse Code Modulation). This method allows for the virtual and actual recording of musical performances, film scores, and other audio samples in a more compact space. Compare the size of a vinyl record (analog) to the size of a CD to get a sense of how much space analog and digital music take up (digital).

Raw Digital Audio

Raw digital audio samples are used in PCM audio recordings. Because they don’t discriminate between recorded information and don’t employ any sort of compression to wipe out unneeded and less significant audio content to minimize file size, high-quality PCM recordings can be lossless. The sample rate and word length are two elements that determine PCM’s performance. The audio waveform is sampled between 8 and 192 thousand times per second by PCM. In 8 to 24 bits, the word length measures the signal-to-noise ratio or available bandwidth. For transmitting various feeds to different speakers, PCM also supports mono, stereo, and multi-channel recordings. The raw PCM data is stored in WAV, AIFF, and AU recording files.

The History of PCM

PCM dates back to 1937 when British engineer Alec Reeves created the technology. In the 1960s, telephone companies began to use the technology to more efficiently send phone calls over large distances between cities. PCM files are much larger than compressed audio files like MP3 files, yet they consume significantly less bandwidth than analog audio. Mu-Law, a PCM telephony technique, is extensively used by telecoms to transfer audio in 64 Kbps PCM data streams. Since the 1960s, many videos and audio recording formats have routinely used or incorporated PCM as an audio recording option.

Devices That Use PCM

The PCM format is commonly used in devices such as audio/video equipment and computers. PCM technology can be found in formats such as 8mm, Hi8, VHS, S-VHS, audio CDs, DVD video, and Blu-ray video. For recording audio via the microphone jack, computer sound cards use the PCM format, and compressed audio can be converted to PCM for playback. PCM-labeled ports are commonly found on TV sets and audio/video equipment for transferring uncompressed audio from the playback device to the TV or receiver.

Alternative Technologies

Instead of PCM, modern telephones can send audio from the microphone to the signal processor using Pulse Density Modulation. Although PCM is simpler to manipulate, PDM has the advantage of picking up less noise and interference from other signals at a low cost. PCM competes with encoded formats such as Dolby Digital, TrueHD, DTS, and DTS-HD in the audio/video arena. Audio/video technology frequently supports many playback formats. Instead of the PCM range of values, Sony’s Super Audio CD technology uses a distinct recording technique called “Direct Stream Digital,” which only records if the audio wave is traveling up or down at sample points.

Pros And Cons Of PCM audio


The increased interference tolerance of digital signal coding, as employed by PCM audio, over a continuous-time transmission. The receiver’s binary coding must only discriminate between high and low signals (0 and 1). Pulse-amplitude modulation, pulse width modulation, pulse phase modulation, pulse frequency modulation, and digital modulation (apart from PCM audio) all have differing “resistance” to systematic and random mistakes. In contrast to other types of modulation, sinusoidal interference (such as Mains hum) can be reduced by regeneration amplifiers with PCM audio-modulated signals. As a result, this strategy has become entrenched not just in communications technology, but also in traditional analog technology ( high fidelity ).


The disadvantage of PCM audio coding is that it necessitates a high data transfer rate (about 1.4 Mbit/s for an audio CD), which is why adapted and enlarged PCM audio methods are employed in various applications and the digital information is decreased by source coding.

PCM basics

Depending on what is being converted, the required quality, and how the information is stored, communicated, and delivered, converting analog audio to digital PCM audio can be difficult.

PCM audio files are essentially digital representations of analog sound waves. The goal is to get as near as feasible to the characteristics of an analog audio signal.

The process of converting from analog to PCM is known as sampling. Unlike PCM, which is a series of 1s and 0s, the emulated sound moves in waves. You must sample precise points in the sound wave from a microphone or other analog audio source to capture analog sound using PCM.

An analog waveform is sampled 44.1 thousand times per second (or 44.1 kHz) on an audio CD, for example, and the point size (bit depth) is 16 bits. In other words, 44.1 kHz/16 bits is the digital audio standard for CD audio.

Home Theater and PCM Audio

PCM audio is utilized in CDs, DVDs, Blu-ray discs, and other digital audio applications. Linear Pulse Code Modulation is the name given to it when it is employed in surround sound applications (LPCM).

CD, DVD, and Blu-ray Disc players read PCM or LPCM signals from discs and can transmit them in two ways: 

By preserving the digital form of the signal and sending it to a home theater receiver via a digital optical, digital coaxial, or HDMI connection; or by sending the signal to a home theater receiver via a digital optical, digital coaxial, or The PCM stream is then converted to an analog signal via the home theater receiver, which may subsequently be sent through the amplifier and speakers. Because the human ear can only hear analog audio signals, PCM transmissions must be converted to analog.

Internally converting the PCM signal to analog format, then sending the rebuilt analog signal over a conventional analog audio connection to a home theater or stereo receiver. In this situation, the sound can be heard by the stereo or home theater receiver without any additional conversion.

Because most CD players only have an analog audio output, the player must convert the PCM signal on the disc to analog internally. Some CD players (and practically all DVD and Blu-ray Disc players) can, however, directly transmit PCM audio signals via digital optical or digital coaxial connections.

Furthermore, most DVD and Blu-ray players can send PCM signals over an HDMI connection. Check your stereo or home theater player’s and receiver’s connection choices.


Knowing what Is Pcm Audio, then High-quality audio files won’t matter if your playing equipment can’t correctly duplicate those sounds, so people who desire the highest quality in their music playback should keep that in mind. Thank you for your time and consideration.

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