Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [pcm]

Pulse-code modulation

Pulse-Code Modulation is a technique used to digitally represent analog signals.

The amplitude of an analog signal is sampled at uniform intervals (at a constant frequency), and each sample is quantized to a numerical value.

Both the sampling frequency and the bit depth (maximum size) of the numerical value determine the fidelity of the stored PCM stream, i.e. how accurately the original analog signal can be reconstructed.

PCM Wikipedia Article

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Audio using PWM, what is the principle behind it?

I have seen a schematic of a PIC board which uses filtered PWM to provide audio output signal to an audio jack. It shows PWM output filtered using 3 stages of passive RC filter followed by an LM386 stage. I have the following questions: Usually an…
quantum231
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PWM, PAM, PCM sine generation and usage confusion

I am confused about something fundamental regarding PWM, PAM and PCM. I am going to be using a speaker's driver analogy to explain my point. As far as I know motors use PWM for power input, I don't know if my scenario with the speaker is any…
Shibalicious
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Why is Pulse Code Modulation called 'modulation' and not 'conversion'?

Since all that a pcm accomplishes is analog to digital conversion, why is it called a modulation technique? There is a message signal but no carrier. According to my knowledge, modulation requires a carrier.
Maxsash
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AKM DAC problem

I’ve been developing the basis for a granular synth and general digital development platform for the past few months. I was using STM32 chips at first, but I’ve switched to bare metal Raspberry Pi for development because it’s faster and…
fredyeah
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Oscilloscope trace shows two voltages at the same time

Sorry if I worded the question strangely, I'm just not exactly sure what's going on. I'm analyzing a PCM audio stream coming out of an ESP32. I've got the DOUT pin connected through a 10x probe to channel one of my scope, and CLK connected to…
nkizz
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I2S TDM channels maximum bandwidth

Does I2S support sending multiple mic (around 20) channel data? If no, what is the limiting factor in supporting multiple mics? Also, is there any way to send multiple channel data from different MICs in any other format other than TDM, if TDM on…
user3053970
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Li-ion BMS/PCM Use Cases

I am building a portable bluetooth speaker. I am using 4 18650 Li-Ion batteries and using 4S 14.8v BMS/PCM charge/discharge protection board with balancing. This board works great, but the challenge is when the board goes into "protection" mode you…
vladiator
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What audible difference will an audio op amp make in an audio ADC

If I were making an audio ADC based upon the PCM1804 for example , what would be the impact on the output audio from the PCM1804 if I used an audio op amp like the OPA1632? What exactly does the op amp do to the audio signal ? I realise it will…
RenegadeAndy
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Interfacting a device's PCM output with a RPi?

I am planning to use a SIM7080G for a future project. However, I am facing an issue with the way it handles audio. The SIM7080G has a PCM interface, which, according to the hardware design guide, is recommended to be used with a NAU88C10. In my…
satyamedh
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How to interpret this PCM audio data?

I am attempting to write a program to get an ATmega328P to play audio. I first tried to use this library but I could not get it to work so I am now attempting to program my own. The problem is that I don't know how to interpret the audio data that I…
luek baja
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Can I use three PDM MEMS microphones with an ESP32, even though it already uses an I2S DAC?

For my design, I need stereo audio output (2 MAX98361 ICs work best imo) and three microphone inputs. I figured, the easiest way to do this was to use 3 digital MEMS microphones, but i don't know if the ESP32-C3FN4 (which is the main MCU of the…
laust0rm
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Interface PCM module SIM800 , SIM808

I am planning to use a SIM800 or SIM808 GSM/GPRS module's PCM interface. I configured the circuit according to the datasheet. I send the 256 kHz clock from the micro to the PCM_CLK pin of the module and apply the following commands to set the PCM to…
ASHKAN
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Customising audio on an arcade game with U6295 audio IC

I have an arcade redemption game that has a U6295 audio IC that plays 4 different soundtracks which are stored on a ST M27C801 EPROM. I would like to flash my own audio onto that EPROM with one of those universal EPROM programmers so the machine can…
Ramsom
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What is the bandwidth formula for pulse code modulation (PCM)?

The image below shows the formula for the bandwidth of pulse code modulation (PCM.) There are two questions I want to ask: Bandwidth of the PCM signal waveform is bounded by \$ B_{PCM} = \frac{1}{2}(R) =\frac{1}{2}(nf_s) \$ R is the bitrate and…
hontou_
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Audio amplifier : how to combine stereo output to mono input

In the following schematic, I would like to decode PCM audio from my Raspberry Pi and output the signal to a 3W speaker. The PAM8302 datasheet is quite light. I don't understand what the input levels are. On the other hand, the PCM5100A PCM decoder…
nowox
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