The pickup as an audio monitoring device, due to its relatively short development time, and the confusion of the concept of many domestic manufacturers, makes everyone think that many manufacturers have the ability to launch digital pickups , that is to say through digital signal processing, and then output the audio signal, but the actual This is not the case. Here are several methods of separate analog and digital pickups for everyone to identify the real digital pickup.
1. The digital pickup is processed by a chip such as a digital signal processing chip. Since the chip itself has reset, start-up, and algorithm running time intervals, a power-on, there will be 1-2S interval to hear the audio output, so you can The pickup is connected to the earphone first and then powered on. If there is an audio output in a moment, it is an analog pickup. If there is a 1-2S interval, it is a digital pickup.
2. All digital pickups first convert the analog audio signal to a digital signal through a digital signal processor's ADC and then convert it into an analog signal, so there must be bandwidth limitations, such as 8K when the sampling rate is set to 16K. The above signal is filtered by the anti-aliasing filter, so the signal above 8K is very small. Spectral analysis through professional recording equipment and recording software can tell whether the pickup is analog or a pickup with a digital signal processor.
3. All digital microphones have the function of software noise reduction and can automatically recognize the difference between human voice and noise. The easiest way is to play a piece of white noise (such as air-conditioning sound, wind noise and other continuous noise) and record through the pickup. If the digital microphone is at the beginning of noise, the noise will be relatively large, and the noise will be after 1 to 2 seconds. It will gradually become smaller. The sound recorded by the analog pickup will remain unchanged.
4. Many pickups claim to have an automatic gain control (AGC) function. Actually AGC is divided into two types. One is analog automatic gain control as shown in the figure below; and there is full digital automatic gain control. The working principle of analog AGC is very simple: when the input signal is greater than a certain amplitude, the output will be saturated. At this time, the output is within a certain range by reducing the entire loop gain. All-digital automatic gain control is much more complicated. The basic principle is to determine the signal-to-noise ratio of the effective signal and noise. When the signal-to-noise ratio is small, the loop gain is increased to improve the recognition of the voice. The signal-to-noise ratio is very high. When properly high, the gain is reduced so that the output does not exceed the limit of the dynamic range and is saturated. And with sonic boom protection, which means that suddenly there is a large sound input, the DSP will automatically limit the output amplitude without saturation and will not output in the next few seconds.
So another way to identify digital pickups and analog pickups is to create a louder sound near the microphone of the pickup, such as a clapping hand. If it is analog, there will be a clear input to close the window and the digital pickup will not. The analog pickups claim to have the basic working principle of AGC. We can clearly see that when the sound suddenly increases, its output is saturated and limited.
1. The digital pickup is processed by a chip such as a digital signal processing chip. Since the chip itself has reset, start-up, and algorithm running time intervals, a power-on, there will be 1-2S interval to hear the audio output, so you can The pickup is connected to the earphone first and then powered on. If there is an audio output in a moment, it is an analog pickup. If there is a 1-2S interval, it is a digital pickup.
2. All digital pickups first convert the analog audio signal to a digital signal through a digital signal processor's ADC and then convert it into an analog signal, so there must be bandwidth limitations, such as 8K when the sampling rate is set to 16K. The above signal is filtered by the anti-aliasing filter, so the signal above 8K is very small. Spectral analysis through professional recording equipment and recording software can tell whether the pickup is analog or a pickup with a digital signal processor.
3. All digital microphones have the function of software noise reduction and can automatically recognize the difference between human voice and noise. The easiest way is to play a piece of white noise (such as air-conditioning sound, wind noise and other continuous noise) and record through the pickup. If the digital microphone is at the beginning of noise, the noise will be relatively large, and the noise will be after 1 to 2 seconds. It will gradually become smaller. The sound recorded by the analog pickup will remain unchanged.
4. Many pickups claim to have an automatic gain control (AGC) function. Actually AGC is divided into two types. One is analog automatic gain control as shown in the figure below; and there is full digital automatic gain control. The working principle of analog AGC is very simple: when the input signal is greater than a certain amplitude, the output will be saturated. At this time, the output is within a certain range by reducing the entire loop gain. All-digital automatic gain control is much more complicated. The basic principle is to determine the signal-to-noise ratio of the effective signal and noise. When the signal-to-noise ratio is small, the loop gain is increased to improve the recognition of the voice. The signal-to-noise ratio is very high. When properly high, the gain is reduced so that the output does not exceed the limit of the dynamic range and is saturated. And with sonic boom protection, which means that suddenly there is a large sound input, the DSP will automatically limit the output amplitude without saturation and will not output in the next few seconds.
So another way to identify digital pickups and analog pickups is to create a louder sound near the microphone of the pickup, such as a clapping hand. If it is analog, there will be a clear input to close the window and the digital pickup will not. The analog pickups claim to have the basic working principle of AGC. We can clearly see that when the sound suddenly increases, its output is saturated and limited.
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