How do you turn a signal into a digital signal, and how do you convert an analog signal into a digit

There is actually a hidden app in the iPhone usage tips, which can be used to detect the iPhone signal, the iPhone cellular network value, and it can accurately display the strength of the mobile phone signal with numbers. And it allows you to switch between the grid and the value by doing the following: the lower the number, the worse the signal.

In general, between -40 and -50 is near the base station;

The signal between 50 and 60 is very good;

The signal between 60 and 70 is considered good;

Between 70 and 80, the signal is slightly weaker;

Between 80 and 90 is a weak signal;

Below 90 is the basic communication state.

100, it is recommended to sleep at night or turn on the airplane mode, otherwise it will consume power and radiate a lot!

Let's go to the detailed steps of the tutorial to check the strength of iPhone signal.

The first step is to enter [**].

The second step is to enter *3001* on the dialpad, and then press the [Call] button, the iOS built-in app Field Test will be launched, and the exact value of the signal strength will also appear in the upper left corner.

Step 3, press and hold your iPhone's on/off key (i.e., the top power key) until the "Slide to power off" slider appears.

Step 4, Finally, press and hold the Home button until the power off slider disappears, the phone will return to the home screen interface, Step 5, at this time, the signal strength value will always be displayed in the upper left corner of the iPhone screen, you can also click on it to switch between the number and the signal bar.

There are three basic processes for the digitization of analog signals:

The first process is "sampling", which is to extract the sample values of analog signals at equal intervals, so that continuous signals become discrete signals.

The second process is called "quantization", which is to transform the extracted sample value into the nearest numerical value, which indicates the size of the sampled value.

The third process is "encoding", which is to represent the quantized value as a set of binary numbers. The digitization of the analog signal can be done through these three processes, a method called "pulse coding".

After the digital signal is transmitted to the receiver, there needs to be a restoration process, that is, the received digital signal is converted back into an analog signal, which can be understood by the receiver. This process is called "digital-to-analog transformation" and reproduces it as a sound or image.

1. Unlock and turn on the phone, and then turn on the dial pad.

2. Enter *3001 * on the keypad and click the dial key.

3. A program appears, and the built-in application Fieid Test of the mobile phone is launched.

4. Next, press the shutdown button, and after the sliding shutdown interface appears, release the power button. Press and hold the home button until the shutdown reminder disappears, so that it can be converted into a number.

5. Double-click the signal key to convert between digital icons.

To digitize an analog signal, it is first necessary to discretize it in time, that is, to replace a continuous infinite number of coordinate positions with a finite number of sampling points in time, a process called sampling.

The so-called sampling is to extract an instantaneous amplitude value of the signal at certain time intervals, which is to discretize the analog signal in time.

The resulting series of sample values that are discrete in time after sampling is called a sample value sequence.

Sampling turns the analog signal into a sequence of sample values that are discrete in time, but the amplitude of each sample value is still a continuous analog quantity, so it must also be discretized and converted into a finite number of discrete values, so that the amplitude can finally be expressed by digital Qi Rujing, and the process of discretizing the sampled value is called quantization, which is to realize the discretization of the amplitude of the continuous signal.

The sampled and quantized signal becomes a series of high-precision pulse signals with amplitude grading, and the stool pants of this string of pulses represent the analog signal, which is not yet a digital signal itself, but a decimal signal, which needs to be converted into a digitally coded pulse, a process called coding.

The simplest way to encode is binary encoding, specifically, to use n-bit binary code to represent the quantized sample value, each binary number corresponds to a quantization level, and then arrange them to obtain a digital information stream composed of binary pulses for transmission and recording.

This digitization process is also known as Pulse Code Modulation (PCM).

With the rapid development of the industry, more and more technologies and new knowledge are emerging, which requires users to learn more in ordinary times, so as to be handy in practical applications.

Digital signals. Meaning that the value of the amplitude is discrete, the amplitude means that it is limited to a finite number of values. Binary.

A code is a digital signal. Binary codes are less affected by noise and are prone to digital circuitry.

so it has been widely used.

Analog signals. The PCM (Pulse Code Modulation) method is typically used to quantize and convert to a digital signal. The PCM method is to make different binary values for different ranges of analog signals.

For example, if we use 8 bits**, we can quantize the analog signal to 2 8 = 256 orders of magnitude.

In practice, we often use 24-bit or 30-bit**. Typically, a digital signal is converted to an analog signal by a carrier phase shift. Computers, LANs, and metro networks all use binary digital signals.

Computers can only process digital signals, while many of the real signals are analog signals, such as voltage, current, etc., which can only be input into the computer for processing if these signals are converted into digital signals.

Because of the popularization of digital technology and the development of integrated circuits, the concept has subverted the traditional measurement and control technology, the traditional analog signal can be measured, but the controllability is poor, with the development of electronic technology, the emergence of high-performance control core, so that the signal can be greatly controlled, and can complete a very humanized human-computer interaction function. But in reality, almost all of the measured data is analog, so in order for the control core to read it, it must first be digitized. Therefore, a good measurement front-end, it can also be said that the sensor has become the key to measurement and control technology, and it is particularly important to collect the analog signal completely, and then accurately convert it into a digital signal, so now many chip manufacturers vigorously promote their A D or D A conversion technology and products.

Here take the Apple mobile phone as an example, or Zen talk about the specific operation as follows:

1. Turn on your iPhone, then enter the home screen, select the ** icon and open it.

2. Enter the interface of **, select the dial pad option in the bottom column, and then click to enter the dialing interface.

3. Enter the command in the dialing interface, which is also the instruction of the engineering test mode, the specific instruction is shown in the figure, and click the dial key after entering the instruction.

4. After that, you will enter the test mode interface of the engineering mode, but it is all in English, and you can see that the icon of the signal is already displayed in digital mode.

5. Next, press and hold the power button of the mobile phone, press and hold the power button until the screen interface shows the logo of sliding to shut down, then let go of the power button, press and hold the home button in the middle until you exit to the main interface, at this time, you can find that the icon of the signal in the upper left corner has become a digital display shirt.

6. Of course, at this time, click on the number signal in the upper left corner, and it will become a five-dot logo, and then click it will become a number, that is, you can switch between each other at this time.

7. If you want to completely change back to the original small dot display, you only need to operate the previous steps again, and then you can do it, and then click the signal icon in the upper left corner will not change.