CN114666030B - Hybrid underground signal encoding and decoding method - Google Patents

Abstract

The invention provides a hybrid downhole signal encoding and decoding method, which includes: a downhole transmitter adds a signal synchronization head to the front end of the modulated acquisition signal, and sends the acquisition signal to a ground receiver in the form of electromagnetic waves; the ground receiver calculates the acquisition The cross-correlation coefficient between the signal and the preset code value of each type of synchronization head, based on the magnitude relationship between the cross-correlation coefficient and the threshold coefficient value of the corresponding type, to determine whether the collected signal is a synchronization head; if it is a synchronization head, according to the synchronization The type of the header and the system setting parameters determine the corresponding demodulation mode; the collected signal is demodulated based on the demodulation mode. The present invention distinguishes the signal type by adding a synchronization header to the front of the information, establishes a synchronization header detection area on the ground receiver and calculates the cross-correlation coefficient to identify the synchronization header type and locate the signal, and selects the corresponding demodulation mode according to the synchronization header type. The class demodulates the acquired signal, taking into account the real-time performance and high precision of the signal.

Description

A hybrid downhole signal encoding and decoding method

technical field

The present invention relates to the field of communications, and more particularly, to a hybrid downhole signal encoding and decoding method.

Background technique

At present, the degree of intelligence in my country's petroleum field is gradually improving, and a large number of downhole equipment has shifted from the traditional wired communication mode to the wireless communication mode. At present, there are three mainstream underground wireless communication methods. Among them, electromagnetic wave communication has developed rapidly in recent years. Many companies have developed underground communication systems based on electromagnetic waves. However, when the electromagnetic wave is transmitted from the well to the surface, it needs to pass through thousands of meters of formation on the way. It is affected by the noise in the formation and the complex mixed impedance network, which often leads to severe distortion when the signal is transmitted to the surface. It must be filtered before decoding. In addition, the structure of the impedance network is complex, and its transfer function is related to various factors such as oil well structure and soil resistivity, which increases the difficulty of signal filtering.

SUMMARY OF THE INVENTION

Aiming at the technical problems existing in the prior art, the present invention provides a hybrid downhole signal encoding and decoding method, including:

The downhole transmitter adds a signal synchronization head to the front end of the modulated acquisition signal, and sends the acquisition signal to the ground receiver in the form of electromagnetic waves;

The ground receiver calculates the cross-correlation coefficient between the collected signal and the preset code value of each type of synchronization header, and judges that the current in the identification area is based on the magnitude relationship between the cross-correlation coefficient and the threshold coefficient value of the corresponding type. Whether the said acquisition signal is a synchronization head;

If it is a sync header, determine the corresponding demodulation method according to the type of the sync header and the system setting parameters;

The acquired signal is demodulated based on the demodulation manner.

On the basis of the above technical solutions, the present invention can also make the following improvements.

Optionally, the downhole transmitter adds a signal synchronization head to the front end of the modulated acquisition signal, including:

According to the type of the collected signal, the downhole transmitter adds a corresponding signal synchronization header to the front end of the collected signal, and the signal synchronization header includes a coding value corresponding to the type of the collected signal, and the type of the collected signal is emergency type or non-essential. The urgent type, the length of the signal synchronization header of the urgent type is smaller than the length of the signal synchronization header of the non-emergency type.

Optionally, the ground receiver calculates the cross-correlation coefficient between the collected signal and the preset code value of each type of synchronization header, based on the magnitude relationship between the cross-correlation coefficient and the threshold coefficient value of the corresponding type, Determining whether the acquisition signal currently in the identification area is a synchronization header includes:

The ground receiver calculates a first cross-correlation coefficient between the acquired signal and the preset code value of the emergency type sync header and a second cross-correlation coefficient between the acquired signal and the preset code value of the non-emergency type sync header. relationship number;

When the first cross-correlation coefficient is less than the emergency threshold coefficient value, the acquired signal is not a synchronization header; or, when the second cross-correlation coefficient is smaller than the non-urgent threshold coefficient value, the acquired signal is not a synchronization header;

When the first cross-correlation coefficient is greater than the emergency threshold coefficient value, the acquired signal is a sync header, and the type of the acquired signal is an emergency type; or, when the second cross-correlation coefficient is greater than the non-emergency threshold coefficient value , the collected signal is a sync header, and the type of the collected signal is a non-emergency type.

Optionally, the ground receiver includes a signal buffer area, the signal buffer area includes a first synchronization header detection area and a second synchronization header detection area, and the length of the signal buffer area satisfies the following conditions:

After the signal synchronizing head of the collected signal enters the second synchronizing head detection area, the entire collected signal should have entered the signal buffer area.

Optionally, the ground receiver calculates the cross-correlation coefficient between the collected signal and the preset code value of each type of synchronization header, based on the magnitude relationship between the cross-correlation coefficient and the threshold coefficient value of the corresponding type, Determining whether the acquisition signal currently in the identification area is a synchronization header includes:

After the first synchronization header detection area of the signal buffer area of the ground receiver receives the acquisition signal, determine whether the acquisition signal is a synchronization header, and if not, wait for the next segment of the acquisition signal to be detected;

If it is determined that the collected signal is an emergency type signal, demodulating the collected signal in real time based on a real-time demodulation method;

If it is judged that the acquisition signal is a non-emergency type signal, enter the second synchronization head detection area for detection, and when the second synchronization head detection area detects that the acquisition signal is a non-emergency type signal again, based on the delay The demodulation method demodulates the collected signal.

Optionally, the calculation formula of the cross-correlation coefficient between the collected signal and the preset code value of each type of synchronization head is:

；

;

；

;

；

;

；

;

为采集信号，

为每一种类型同步头的预设码值，N为采集信号长 度，

的取值范围为0~1。 in

To collect the signal,

is the preset code value of each type of sync header, N is the length of the collected signal,

The value range is 0~1.

Optionally, the emergency threshold coefficient value and the non-emergency threshold coefficient value are obtained by calculating in the following manner:

The downhole transmitter sends the known correction code to the surface receiver, and the surface receiver calculates the third cross-correlation coefficient between the received correction code and the original known correction code;

The emergency threshold coefficient value and the non-emergency threshold coefficient value are determined according to the third cross-correlation coefficient, wherein the emergency threshold coefficient value is smaller than the non-emergency threshold coefficient value.

Optionally, determining the corresponding demodulation mode according to the type of the synchronization header and the system setting parameters, including:

If the type of the synchronization header is an emergency type, it is determined that the demodulation mode is a real-time demodulation mode: real-time acquisition signals can be obtained by using Butterworth or Chebyshev low-pass filtering to perform real-time filtering;

If the type of the synchronization head is a non-emergency type, determine that the demodulation mode is a delay demodulation mode: wait for the end of signal acquisition, and use an ideal low-pass filter to obtain a high-precision delay signal;

If the system is set to hybrid filter demodulation mode, first use Butterworth or Chebyshev filter to obtain real-time acquisition signal, and then use ideal low-pass filter to obtain high-precision signal to replace the previously obtained real-time acquisition signal after receiving the real-time acquisition signal. Acquire the Signal.

Optionally, also include:

The ground receiver calculates the phase-frequency response and amplitude-frequency response of the formation impedance network at this time according to the received correction code;

Correspondingly, demodulating the collected signal based on the demodulation method includes:

Phase compensation and amplitude compensation are performed on the collected signal based on the demodulation method.

The invention provides a hybrid downhole signal encoding and decoding method, which distinguishes the signal type by adding a synchronization head to the front of the information, identifies the synchronization head type and locates it by establishing a synchronization head detection area in a ground receiver and calculating the cross-correlation coefficient. According to the type of synchronization head, select the corresponding demodulation method to demodulate the collected signal, taking into account the real-time performance and high precision of the signal.

Description of drawings

1 is a flowchart of a hybrid downhole signal encoding and decoding method provided by the present invention;

2 is a schematic diagram of a signal buffer area;

FIG. 3 is a schematic diagram of the overall flow of the hybrid downhole signal encoding and decoding method.

Detailed ways

The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments. The following examples are intended to illustrate the present invention, but not to limit the scope of the present invention.

Example 1

A hybrid downhole encoding and decoding method, see Figure 1, the method mainly includes the following steps:

S1, the downhole transmitter adds a signal synchronization head to the front end of the modulated acquisition signal, and sends the acquisition signal to the ground receiver in the form of electromagnetic waves.

As an embodiment, the downhole transmitter adds a signal synchronization header to the front end of the modulated acquisition signal, including: according to the type of the acquired signal, the downhole transmitter adds a corresponding signal synchronization header to the front end of the acquired signal, and the signal The synchronization header includes a coded value corresponding to the type of the collected signal, the type of the collected signal is an emergency type or a non-emergency type, and the length of the emergency type signal synchronization header is smaller than the length of the non-emergency type signal synchronization header.

It can be understood that the downhole transmitter can be a downhole sensor. After the downhole sensor collects the required data, it is modulated by frequency modulation or amplitude modulation. way to send the signal to the ground.

Among them, the signal synchronization header includes a code value that can characterize the type of the collected signal, wherein the corresponding relationship between the code value and the signal type is shown in Table 1 below.

Table 1 Correspondence table of coding value and signal type

According to Table 1, for example, when the signal collected by the sensor is a non-emergency type signal, you can set coded values such as 000, 001, and 010 in the synchronization header. If the downhole sensor collects an air pressure signal and is an emergency signal, then The 00 code value can be set in the synchronization header, and after the code value is set in the synchronization header at the front end of the acquisition signal, the acquisition signal is sent to the ground.

Among them, the downhole transmitter adds the corresponding synchronization header according to the signal type. When the signal is an emergency signal, the emergency signal synchronization header is added, and when the signal is a non-emergency signal, the non-emergency signal synchronization header is added. The emergency signal sync header should be shorter than the non-emergency signal sync header to improve the demodulation speed of the emergency signal. The length of the signal synchronization head can be customized, and it can contain information or only be used to locate the signal position without any meaning. Preferably, in order to improve the calculation efficiency of the system, on the premise that the synchronization head can play its due role, its length should as short as possible. Specifically, in this embodiment, the emergency signal synchronization header takes 2 bits, the non-emergency signal synchronization header takes 3 bits, and the code value table is shown in Table 1 above.

S2, the ground receiver calculates the cross-correlation coefficient between the collected signal and the preset code value of each type of synchronization header, and judges that the current identification Whether the acquisition signal in the area is a sync header.

S3, if it is a synchronization header, determine the corresponding demodulation mode according to the type of the synchronization header and the system setting parameters.

It can be understood that after receiving the acquisition signal, the ground receiver calculates the cross-correlation coefficient between the acquisition signal and the preset code values of the synchronization headers of different types, based on the correlation between the cross-correlation coefficient and the threshold coefficient value of the corresponding type. The size relationship determines whether the current acquisition signal in the identification area is a sync header, and the type of the acquired signal, that is, whether the acquired signal is an emergency type signal or a non-emergency type signal.

As an embodiment, the calculation formula of the cross-correlation coefficient between the acquisition signal and the preset code value of each type of synchronization head is:

；

;

；

;

；

;

；

;

为采集信号，

为每一种类型同步头的预设码值，N为采集信号长 度，

的取值范围为0~1。 in

To acquire the signal,

is the preset code value of each type of sync header, N is the length of the collected signal,

The value range is 0~1.

As an embodiment, the ground receiver calculates the cross-correlation coefficient between the collected signal and the preset code value of each type of synchronization header, and determines that the current is in the identification area based on the magnitude relationship between the cross-correlation coefficient and the threshold coefficient value of the corresponding type. Whether the acquisition signal is a synchronization head, including: the ground receiver calculates the first cross-correlation coefficient between the acquisition signal and the preset code value of the emergency type synchronization head, and the acquisition signal and the non-emergency type synchronization head. The second cross-correlation coefficient between preset code values; when the first cross-correlation coefficient is less than the emergency threshold coefficient value, the acquired signal is not a synchronization header; or, when the second cross-correlation coefficient is less than the non-emergency threshold coefficient value, The acquisition signal is not a synchronization header; when the first cross-correlation coefficient is greater than the emergency threshold coefficient value, the acquisition signal is a synchronization header, and the type of the acquired signal is an emergency type; or, when the second cross-correlation coefficient is greater than the non-urgent threshold coefficient value , the acquisition signal is a sync header, and the type of the acquired signal is a non-emergency type.

It can be understood that, according to Table 1 above, there are mainly two types of signals, emergency type and non-emergency type. According to the above table 1, there are four preset code values for the synchronization header of the emergency type, and the synchronization header of the non-emergency type. There are also four preset code values. Then, the ground receiver calculates the cross-correlation coefficient for each preset code value corresponding to the collected signal and the emergency type, calculates four first cross-correlation coefficients, and compares the correlation between each first cross-correlation coefficient and the emergency threshold coefficient value. If the four first cross-correlation coefficients are all smaller than the emergency threshold coefficient value, then the acquired signal is not a sync header, and the next signal needs to be detected; if one of the first cross-correlation coefficients is greater than the emergency threshold coefficient value, the acquired signal is the sync header, and the collected signal type is the emergency type.

Similarly, the ground receiver calculates the cross-correlation coefficient between the collected signal and each preset code value corresponding to the non-emergency type, calculates four second cross-correlation coefficients, and compares each second cross-correlation coefficient with the non-emergency threshold coefficient value If the four second cross-correlation coefficients are all smaller than the non-emergency threshold coefficient value, then the acquired signal is not a synchronization head, and the next segment signal needs to be detected; if one of the second cross-correlation coefficients is greater than the non-emergency threshold coefficient value, the collected signal is a sync header, and the collected signal type is a non-emergency type.

The emergency threshold coefficient value and the non-emergency threshold coefficient value are calculated in the following manner: the underground transmitter sends a known correction code to the ground receiver, and the ground receiver calculates the received correction code and the original known correction code The third cross-correlation coefficient between the two; according to the third cross-correlation coefficient, determine the emergency threshold coefficient value and the non-emergency threshold coefficient value, wherein the emergency threshold coefficient value is smaller than the non-emergency threshold coefficient value .

取0.7，非紧急 门限系数值

取0.9。 It can be understood that the threshold coefficient value should be calculated from the received result of the correction code. The attenuation degree of the signal is related to the oil well structure and soil resistivity, and the signal will change in phase and amplitude during transmission. The downhole transmitter will transmit a known correction code before transmitting the signal. After receiving the code, the ground receiver will calculate the cross-correlation coefficient between the received code and the original transmitted correction code to calculate the threshold coefficient used this time, including emergency threshold coefficient value and non-emergency threshold coefficient value, specifically, in this embodiment, the emergency threshold coefficient value

Take 0.7, the non-emergency threshold coefficient value

Take 0.9.

Wherein, as an embodiment, the ground receiver includes a signal buffer area, the signal buffer area includes a first synchronization header detection area and a second synchronization header detection area, and the length of the signal buffer area satisfies the following conditions: when the signal of the collected signal is synchronized After the header enters the second sync header detection area, the entire acquisition signal should have entered the signal buffer area. Preferably, the length of the signal buffer area should leave a margin under the condition that the above conditions are met, so as to prevent data loss caused by signal truncation.

It can be understood that, after receiving the acquisition signal, the ground receiver stores the acquisition signal in the signal buffer area, and the acquisition signal is detected by the synchronization head detection area of the signal buffer area.

As an embodiment, the ground receiver calculates the cross-correlation coefficient between the collected signal and the preset code value of each type of synchronization header, and determines that the current identification Whether the acquisition signal in the area is a synchronization header includes: after the first synchronization header detection area of the signal buffer area of the ground receiver receives the acquisition signal, judging whether the acquisition signal is a synchronization header, and if it is not a synchronization header If it is judged that the collected signal is an emergency type signal, real-time demodulation is performed on the collected signal based on the real-time demodulation method; if it is judged that the collected signal is a non-emergency type signal, then Enter the second synchronization head detection area for detection, and when the second synchronization head detection area detects that the collected signal is a non-emergency type signal again, the collected signal is demodulated based on the delay demodulation method.

It can be understood that the signal buffer area of the ground receiver includes a first synchronization head detection area and a second synchronization head detection area, and the second synchronization head detection is performed on the received acquisition signal. Specifically, when the first synchronization head detection area detects that the acquisition signal is not a synchronization head, wait for the detection of the next segment of the signal; if the first synchronization head detection area detects that the acquisition signal is an emergency type signal, the real-time solution is immediately used. The acquisition signal is demodulated by the modulation method; if the acquisition signal is detected as a non-emergency signal in the first synchronization head detection area, wait for a period of time and perform the second synchronization head detection. If the acquisition signal is detected again, it is still non-emergency. Only when the type of signal is detected, the acquired signal is demodulated by means of delay demodulation.

S4, demodulate the collected signal based on the demodulation manner.

As an embodiment, determining the corresponding demodulation mode according to the type of the synchronization header and the system setting parameters includes: if the type of the synchronization header is an emergency type, determining that the demodulation mode is a real-time demodulation mode: adopting Butterworth or Cheby The real-time acquisition signal can be obtained by performing real-time filtering by Scheff low-pass filtering; if the type of the synchronization head is a non-emergency type, determine that the demodulation mode is a delayed demodulation mode: wait for the end of signal acquisition, and use an ideal low-pass filter to obtain high precision Delay signal; if the system is set to hybrid filter demodulation mode, first use Butterworth or Chebyshev filter to get real-time acquisition signal, and then use ideal low-pass filter to get high-precision signal instead after real-time acquisition signal is received The real-time acquisition signal obtained before.

It can be understood that it is detected whether the collected signal is an emergency signal or a non-emergency signal. If it is an emergency signal, the real-time demodulation method is used for demodulation; if it is a non-emergency signal, the delay demodulation method is used for demodulation. However, if the system is set to mixed filtering, no matter whether the collected signal is an emergency signal or a non-emergency signal, it will be demodulated according to the filtering and demodulation mode set by the system.

It should be noted that the ground receiver calculates the phase-frequency response and amplitude-frequency response of the formation impedance network at this time according to the received correction code; in the subsequent demodulation process, phase compensation and amplitude compensation are performed on the acquired signal.

Embodiment 2

A hybrid downhole signal encoding and decoding method, see Figure 3, the main process of the method includes: the downhole transmitter sends the acquisition signal including the signal synchronization head to the ground receiver, after the ground receiver receives the acquisition signal, calculates the acquisition signal and the acquisition signal. The cross-correlation coefficient between the preset code values of each type of synchronization header is determined according to the magnitude relationship between the cross-correlation coefficient and the threshold coefficient value to determine whether the collected signal is a synchronization header and the type of the collected signal. According to the type of the collected signal, a corresponding signal demodulation method is used to demodulate the collected signal.

The present invention provides a hybrid downhole signal encoding and decoding method. The attenuation amplitude of the formation impedance network is determined by the correction code, and the threshold coefficient of the signal is determined based on this, and the formation impedance network is calculated by comparing the received correction code and the original code. The amplitude-frequency response and phase-frequency response of the signal are then compensated for the amplitude and phase of the received signal. The signal type is distinguished by adding a synchronization header to the front of the information, the synchronization header is identified and the signal is located by establishing a synchronization header detection area in the ground receiver and the cross-correlation coefficient is calculated, and finally the real-time and high-speed signals are taken into account by setting up a buffer area. precision.

It should be noted that, in the foregoing embodiments, the description of each embodiment has its own emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

Although preferred embodiments of the present invention have been described, additional changes and modifications to these embodiments may occur to those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be construed to include the preferred embodiment and all changes and modifications that fall within the scope of the present invention.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Thus, provided that these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims (9)

1. a hybrid downhole signal encoding and decoding method, is characterized in that, comprises: The downhole transmitter adds a signal synchronization head to the front end of the modulated acquisition signal, and sends the acquisition signal to the ground receiver in the form of electromagnetic waves; The ground receiver calculates the cross-correlation coefficient between the collected signal and the preset code value of each type of synchronization header, and judges that the current in the identification area is based on the magnitude relationship between the cross-correlation coefficient and the threshold coefficient value of the corresponding type. Whether the said acquisition signal is a synchronization head; If it is a sync header, determine the corresponding demodulation method according to the type of the sync header and the system setting parameters; The acquired signal is demodulated based on the demodulation manner. 2. The hybrid downhole signal encoding and decoding method according to claim 1, wherein the downhole transmitter adds a signal synchronization head to the modulated acquisition signal front end, comprising: According to the type of the collected signal, the downhole transmitter adds a corresponding signal synchronization header to the front end of the collected signal, and the signal synchronization header includes a coding value corresponding to the type of the collected signal, and the type of the collected signal is emergency type or non-essential. The urgent type, the length of the signal synchronization header of the urgent type is smaller than the length of the signal synchronization header of the non-emergency type. 3. The hybrid downhole signal encoding and decoding method according to claim 1 or 2, wherein the ground receiver calculates the cross-correlation coefficient between the acquired signal and the preset code value of each type of synchronization head, Based on the magnitude relationship between the cross-correlation coefficient and the threshold coefficient value of the corresponding type, judging whether the acquisition signal currently in the identification area is a synchronization header, including: The ground receiver calculates a first cross-correlation coefficient between the acquired signal and the preset code value of the emergency type sync header and a second cross-correlation coefficient between the acquired signal and the preset code value of the non-emergency type sync header. relationship number; When the first cross-correlation coefficient is less than the emergency threshold coefficient value, the acquired signal is not a synchronization header; or, when the second cross-correlation coefficient is smaller than the non-urgent threshold coefficient value, the acquired signal is not a synchronization header; When the first cross-correlation coefficient is greater than the emergency threshold coefficient value, the acquired signal is a sync header, and the type of the acquired signal is an emergency type; or, when the second cross-correlation coefficient is greater than the non-emergency threshold coefficient value , the collected signal is a sync header, and the type of the collected signal is a non-emergency type. 4 . The hybrid downhole signal encoding and decoding method according to claim 3 , wherein the ground receiver includes a signal buffer area, and the signal buffer area includes a first synchronization header detection area and a second synchronization area. 5 . Header detection area, the length of the signal buffer area satisfies the following conditions: After the signal synchronizing head of the collected signal enters the second synchronizing head detection area, the entire collected signal should have entered the signal buffer area. 5. The hybrid downhole signal encoding and decoding method according to claim 4, wherein the surface receiver calculates the cross-correlation coefficient between the acquired signal and the preset code value of each type of synchronization head, based on the The magnitude relationship between the cross-correlation coefficient and the threshold coefficient value of the corresponding type, to determine whether the acquisition signal currently in the identification area is a synchronization header, including: After the first synchronization header detection area of the signal buffer area of the ground receiver receives the acquisition signal, determine whether the acquisition signal is a synchronization header, and if not, wait for the next segment of the acquisition signal to be detected; If it is determined that the collected signal is an emergency type signal, demodulating the collected signal in real time based on a real-time demodulation method; If it is judged that the acquisition signal is a non-emergency type signal, enter the second synchronization head detection area for detection, and when the second synchronization head detection area detects that the acquisition signal is a non-emergency type signal again, based on the delay The demodulation method demodulates the collected signal. 6. The hybrid downhole signal encoding and decoding method according to claim 1, wherein the calculation formula of the cross-correlation coefficient between the acquired signal and the preset code value of each type of synchronization head is:

;

;

;

; in

To collect the signal,

is the preset code value of each type of sync header, N is the length of the collected signal,

The value range is 0~1. 7. The hybrid downhole signal encoding and decoding method according to claim 3, wherein the emergency threshold coefficient value and the non-emergency threshold coefficient value are obtained by calculating in the following manner: The downhole transmitter sends the known correction code to the surface receiver, and the surface receiver calculates the third cross-correlation coefficient between the received correction code and the original known correction code; The emergency threshold coefficient value and the non-emergency threshold coefficient value are determined according to the third cross-correlation coefficient, wherein the emergency threshold coefficient value is smaller than the non-emergency threshold coefficient value. 8. The hybrid downhole signal encoding and decoding method according to claim 1 or 5, characterized in that, determining the corresponding demodulation mode according to the type of the synchronization header and the system setting parameter, comprising: If the type of the synchronization header is an emergency type, it is determined that the demodulation mode is a real-time demodulation mode: real-time acquisition signals can be obtained by using Butterworth or Chebyshev low-pass filtering to perform real-time filtering; If the type of the synchronization head is a non-emergency type, determine that the demodulation mode is a delay demodulation mode: wait for the end of signal acquisition, and use an ideal low-pass filter to obtain a high-precision delay signal; If the system is set to hybrid filter demodulation mode, first use Butterworth or Chebyshev filter to obtain real-time acquisition signal, and then use ideal low-pass filter to obtain high-precision signal to replace the previously obtained real-time acquisition signal after receiving the real-time acquisition signal. Acquire the Signal. 9. The hybrid downhole signal encoding and decoding method according to claim 7, further comprising: The ground receiver calculates the phase-frequency response and amplitude-frequency response of the formation impedance network at this time according to the received correction code; Correspondingly, demodulating the collected signal based on the demodulation method includes: Phase compensation and amplitude compensation are performed on the collected signal based on the demodulation method.

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