What does the frequency, bitrate, and bits of an audio file mean?

In simple terms, the sample rate and bit rate are like horizontal and vertical coordinates on the coordinate axis.

The abscissa sampling rate indicates the number of samples per second.

The bitrate of the ordinate represents the accuracy of quantifying analog quantities with digital quantities.

The sampling rate is similar to the number of frames in a moving image, for example, the sampling rate of a movie is 24 Hz, the sample rate of PAL is 25 Hz, and the sample rate of NTSC is 30 Hz. When we play back the sampled still images at the same sampling rate, we see a continuous picture. In the same way, when a CD recorded at the sample rate is recorded at the same rate**, a continuous sound can be heard.

Obviously, the higher this sampling rate, the more coherent the sound you hear and the image you see. Of course, the sampling rate that human hearing and visual organs can distinguish is limited, which is basically higher than the sampled sound, and the vast majority of people are no longer aware of the difference.

The number of bits of the sound is equivalent to the number of colors of the picture, indicating the amount of data for each sample, of course, the larger the amount of data, the more accurate the sound playback, so as not to confuse the sound of the boiling kettle with the whistle of the train. In the same way, it is clearer and more accurate for the picture, so as not to confuse blood with tomato sauce. However, due to the functional limitations of human organs, 16-bit sound and 24-bit picture are basically the limit of ordinary humans, and higher digits can only be distinguished by instruments.

For example, ** is a 7-bit sound sampled at 3kHz, and CD is a sampled 16-bit sound, so CD is clearer than **.

When you understand the above two concepts, bitrate is easy to understand. For example, if there are 3000 samples per second, and each sample is 7 bits, then the bit rate of ** is 21000. The CD is 44100 samples per second, two channels, each sampling is 13-bit PCM encoding, so the bit rate of CD is 44100*2*13=1146600, that is to say, the amount of data per second of CD is about 144KB, and the capacity of a CD is 74 minutes is equal to 4440 seconds, which is 639360KB 640MB.

Frequency response is an evaluation criterion for the frequency response ability of the *****'s digital-to-analog converter. A good frequency response is that a stable enough signal can be output at each frequency point, and the signal size is the same between different frequency points. However, in the low-frequency and high-frequency sections, it is difficult to reconstruct the signal, so there is usually attenuation in these two frequency bands.

The better the output quality of the device, the farther the frequency response curve, on the contrary, not only does it decay quickly at high and low frequencies, but it may also show jitter in the general frequency band.

The range of the human ear to the sound is 20Hz 20kHz, and the audio signal must always maintain a linear response effect in this range. The sound below 20Hz can not be heard but can be perceived by other human sensory organs, that is, the so-called bass dynamics can be felt, so in order to perfectly ** various musical instruments and language signals, the amplifier must achieve the goal of high fidelity, in order to reproduce the harmonics of the tone. Therefore, the frequency band of the amplifier should be extended, the lower limit should be extended to below 20Hz, and the upper limit should be increased to more than 20000Hz.

This range is exactly the range of sound frequencies that can be heard by the human ear: the lowest frequency is from 20Hz all the way up to the highest frequency of 20kHz, and the human ear cannot hear below 20Hz and above 20kHz. At present, the working frequency range of the general power amplifier of the ***** is 20Hz-20kHz.

The bit rate in sound refers to the amount of binary data per unit time after converting an analog sound signal into a digital sound signal, which is an indirect measure of audio quality. The higher the ratio of the higher the noise rate, the better the quality of the pitch.

The bit rate is the number of bits transmitted per second. The higher the bit rate, the faster the data can be transferred. ** Bit rate refers to the amount of binary data per unit of time after the analog signal is converted to a digital signal.

As a reference index of digital ** compression efficiency, bit rate indicates the speed of the number of bits transmitted per unit of time, that is, within 1 second. Usually use thousands of knots per second as a unit, colloquially speaking, it is 1000 per second.

The bit rate is the number of data bits transmitted between the single block bits during data transmission, and the general unit is kbps, that is, thousands per second.

The larger the sampling rate per unit time, the higher the accuracy, and the closer the processed file is to the original file, that is, the richer the details of the picture. But the file size is proportional to the sampling rate, so almost all encoding formats pay attention to how to use the lowest bit rate to achieve the least distortion, around the core of Sun Shirt derived from CBR (fixed bit rate) and VBR (variable bit rate), are all articles made in this regard, but things are not absolute, from the audio aspect, the higher the bit rate, the smaller the proportion of compression, the smaller the sound quality loss, and the closer to the sound quality of the sound source.

Bitrate refers to the number of bits transmitted per second.

The bit rate in refers to the amount of binary data per unit time after the analog sound signal is converted into a digital sound signal, which is an indirect measure of audio quality.

The bitrate sampling frequency is based on Nyquist's sampling theory, which states that in order to turn an analogue signal into a discrete symbol, the frequency of sampling should be at least twice that of the original signal. The hearing limit of the human ear is about 20kHz, which is why Philips set it up when it launched the CD in 1982.

Bit rate refers to the number of bits transmitted per second, also known as the data signal rate, in bits (bits or bps), kilobit seconds (kbits or kbps, k=1000) or megabit seconds (mbit s or mbps, m=1000000). The higher the bit rate, the more data per unit time difference will be transmitted.

If a signal element can only represent 1 bit, then the baud rate and the bit rate are equal. If a symbol can represent n bits of information, then the bit rate is n times the baud rate.