Justme
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A question about sampling rate of cosine signal
21 votes

It is actually not distorted, it is sampled at high enough rate. What fools you is the straight lines drawn between sample points, it gives you a false impression of the waveform. It shows you a ...

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CD quality bitrate
11 votes

What is missing from your calculations is that it requires a multiplier of two because CD quality audio is two channels for stereo. 2 * 44.1 kHz * 16 = 1411.2 kbps The answer to your second question ...

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What is the gain (advantage) of oversampling and noise shaping in D/A conversion?
Accepted answer
9 votes

If you play 16-bit audio at 48kHz, you need the DAC analog reconstruction filter to pass 20kHz and attenuate 96dB at 24kHz, which is quite steep and requires complex multistage analog filter. The ...

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Actual Sample Rate slightly off?
Accepted answer
5 votes

If you calculate the error, 44102/44100 is only about 45 parts per million. That is well within operating tolerance of many crystal oscillators used in consumer equipment to generate audio sampling ...

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Discrete Cosine Transform
5 votes

No, because DCT is not a compression algorithm itself. But different lossy compression algorithms do use DCT as part of the process. DCT can be used to transform data such as audio or image data into ...

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How to rasterise a greyscale image using only black & white pixels?
Accepted answer
4 votes

The process of converting a grey scale image to 1-bit image of black and white pixels is called dithering. There are multiple different algorithms to achieve it with different looking results. Try the ...

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Produce musical signal from instantaneous frequency
Accepted answer
4 votes

The f[i] * i together determine the phase and frequency at every i so sine wave is only rendered correctly if there is no speed change, so the algorithm must be changed to allow for continuous time i ...

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Does a .wav file created from a .mp3 file have better quality than the .mp3 file itself?
3 votes

MP3 is a lossy compression format, so encoding an uncompressed lossless WAV file to MP3 will lose some quality in the encoding process. Decoding a MP3 file back to WAV file has at most the same ...

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Restore RGB Values from Luminance Value?
3 votes

No, because luminance is a weighted sum of RGB components and has no color information, so it is greyscale only.

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Why does the Y component in YCbCr represent luma/intensity?
3 votes

Focus on the first equation for EY. Back in the day when color television was being developed, the color signal had to be compatible with black and white TVs and vice versa. So the compatible ...

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Edge Detection Convolution Intuition
2 votes

If it helps, try a simpler version. Just look at two neighbouring pixels in a row. First example: There is 10 and 10. Difference between them is 0, no difference, no edge. Second example: In the ...

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Perfect lossless rotation of JPEG image (ITU 81)
Accepted answer
2 votes

The basic unit for color components is 8 by 8 only if no chroma subsampling is used, i.e 4:4:4 format. Most likely your test image uses this, but not all images do. When 4:2:2 chroma subsampling is ...

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Why do we use Difference RGB to grayscale function?
Accepted answer
2 votes

There are different color spaces. Each of them has different coefficients for calculating gamma-corrected luma from gamma-corrected RGB values. You have listed coefficients for calculating luma ...

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How the Grayscale images are converted back to RGB?
2 votes

It is not possible to get color back. A grayscale image can be converted to RGB image, by copying the grayscale data to all three RGB channels,but it will still be grayscale. Note that in general, ...

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displaying an image
Accepted answer
2 votes

2160p usually means standard UHD resolution of 3840 x 2160. P means progressive video so it is not interlaced video, but in this case it may just only mean the resolution. Resolution of camera and ...

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reconstruction filter - How does it actually work?
2 votes

A quick answer, but as human hearing does not go past 20kHz bandwidth, 44.1 kHz is enough for storing and transmitting audio. The problem is that the analog antialiasing filter before ADC must be ...

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Phase information of a signal when creating a spectrogram
2 votes

Yes, you are correct. If you take a DFT of square wave and only look at the amplitudes, doing an inverse DFT but using different or random phases for the sine components, it does not look like square ...

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Effective bit depth of mixed signals
1 votes

It would be enough to divide by three, but dividing by 4 might be faster as it can be just be shifted by two. And yes, if only one 16-bit sine channel is playing, it would make the resulting output ...

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Aliasing in continous-time signal
Accepted answer
1 votes

There is aliasing at 3 kHz and 4.5 kHz. The 2 kHz does not, but since 2 kHz and 3 kHz are equally far apart from the 2.5 kHz Nyquist frequency, they look similar. Same with why 0.5 kHz and 4.5 kHz ...

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Difference between delta modulation and differential PCM
1 votes

Since the encoded values are differences between original values, the values are relatively small values and they are in general distributed as small positive and negative values around zero. This ...

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Number of samples in a discrete signals after sampling a continuous periodic signal should be integer?
Accepted answer
1 votes

There is nothing unordinary about it. Signals can have a period that is not an integer multiple of samples, and that is normal. For example, if you record a 440 Hz sine wave with a sampling rate of 48 ...

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Next steps for analyzing this PWM algorithm and choosing a low pass filtering technique?
1 votes

The pulse generation algorithm sounds like it is more like Pulse Density Modulation (PDM), not Pulse Width Modulation (PWM), because PWM would pack the ones into the beginning of counting, and leave ...

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change in size of an individual pixel?
1 votes

A 100x100 pixel image is always a 100x100 pixel image. You can print it with 100 DPI printer, and it will produce 1x1 inch picture. A 50 DPI printer will produce 2x2 inch picture because it makes ...

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In process of image zooming, Sampling rate changes or stays constant?
Accepted answer
1 votes

Yes, it changes the sampling rate. Just like with audio, 1 kHz tone is 1 kHz tone after resampling from 48kHz to 96kHz. So the image has same content, but with more pixels.

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How to properly convert from dB back to amplitude
1 votes

You have the abs(X) in the formula, which is not a reversible operation. All the negative values in the original audio sample has been converted to positive.

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Manipulating line level signals
Accepted answer
1 votes

Audio signals on line level outputs are AC signals with no DC bias, so they run positive and negative around the 0V level. Many devices support 2VRMS output for full scale signal, so that is about 5....

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How to Downsample The Chrominance Components
Accepted answer
1 votes

For demonstration purposes GIMP is just fine. It can split an image to three separate YUV/YCbCr images. You can then manually resize the UV/CbCr images by any amount to downsample the chroma. Then ...

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what is the difference between YUV format and HSV format?
1 votes

YUV, YPbPr and YCbCr are all basically same, but just with different scale factors for the signals. YUV signals are used when encoding/decoding analog composite video, YPbPr signals exists at analog ...

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Camera image pixel structure origin
1 votes

It looks like that is a color camera with the Bayer pattern, and the color camera data is directly used as grayscale data, as if it was coming from a grayscale camera. If it is a color camera, the ...

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Questions on Need of filtering before decimation?
Accepted answer
1 votes

If you think for a moment why you filter, it is to remove frequencies that would fold to the remaining bandwidth when decimating. So if these frequencies that would fold do not exist in the audio ...

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