Guangzhou Sizheng Technology teaches you to identify analog pickups and digital pickups
As an audio monitoring device, the pickups have a short development time and involve privacy. Many people in the country are confusing their concepts, making everyone think that many manufacturers have the ability to launch digital pickups, that is, through digital signal processing and then output. audio signal. Guangzhou Sisi has many years of research and development experience in the field of audio processing and communications. For the distinction between analog and digital microphones, Sizheng has its own unique identification method.
The digital microphone is handled by a chip such as a digital signal processing chip. Since the chip itself has reset, startup, and algorithm running time intervals, it will cause a 1-2S time interval to hear the audio output. Therefore, the pickup can be installed first. Connect headphones, and then turn on the power. If there is an audio output in an instant, it is an analog pickup. If there is a 1-2S interval, it is a digital pickup.
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 setting the sampling rate of 16K above 8K. The 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.
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 setting the sampling rate of 16K above 8K. The 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.
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 the other 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.
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