阅读说明：本技术 一种抗干扰接收机中数字信号处理字长截断方法 (Digital signal processing word length truncation method in anti-interference receiver ) 是由 姚慰 杜健 周康燕 张海堂 龚珊 汪峰 曾理 任浩 肖剑峰 于 2021-11-12 设计创作，主要内容包括：本发明提出了一种抗干扰接收机中数字信号处理字长截断方法,属于数字信号处理技术领域,该方法通过估计截断前数据的功率,然后自适应地调整增益将截断前的数据放大到满幅状态,最后从最高位截取规定字长的数据。与传统方法相比,本发明对截断前的数据功率变化不敏感,可将数字信号处理字长截断引起的信噪比损耗降到最小。(The invention provides a digital signal processing word length truncation method in an anti-interference receiver, which belongs to the technical field of digital signal processing. Compared with the traditional method, the method is insensitive to the power change of the data before truncation, and can reduce the loss of the signal-to-noise ratio caused by truncation of the word length of the digital signal processing to the minimum.)

1. A digital signal processing word length truncation method in an anti-interference receiver is characterized by comprising the following steps:

step 1: estimating the power of digital signal data before truncation, then adjusting the gain of an amplifier, and amplifying the acquired digital signal data by using the amplifier;

step 2: calculating the average power of the amplified digital signal data;

and step 3: calculating a difference between the average power of the amplified digital signal data and the desired power;

and 4, step 4: updating the gain of the amplifier according to the difference between the calculated average power and the expected power;

and 5: data of a prescribed word length is cut out from the most significant bit of the amplified digital signal data.

2. The method for truncating the digital signal processing word size in an antijamming receiver as claimed in claim 1, wherein the specific operations of step 1 are:

step 1.1: setting the received digital signal data asA is a signed integer with word length of a bits, a is a self-defined value; wherein n is a data index number and is a positive integer;

step 1.2: using amplifiers for receiving digital signal dataCarrying out amplification, wherein the specific amplification formula is as follows:

；

in the formula (I), the compound is shown in the specification,for amplified digital signal data ofaThe signed number of bits;for the gain at the k-th amplification operation of the amplifier, ofa+4 bit positive integer, setting initial value of amplifierIs 2 ^a+4-1; k is the number of amplification operations;Nthe length of data for each operation;for the rounding function, the rounding rule is to round the integer closest to zero.

3. The method of claim 2, wherein the data length N per operation is an exponential multiple of 2.

4. The method for truncating the digital signal processing word size in an antijamming receiver of claim 2, wherein the specific operation of the step 2 is as follows:

step 2.1: calculating the instantaneous power of the amplified digital signal data;

step 2.2: calculating the average power of the amplified digital signal data;

step 2.3: the desired power of the amplified digital signal data is calculated.

5. The method according to claim 4, wherein the specific operations of step 2.1 are:

the instantaneous power of the amplified digital signal data is calculated according to the following formula:

；

in the formula (I), the compound is shown in the specification,instantaneous power of the amplified digital signal data is 2aA positive integer of bits.

6. The method according to claim 4, wherein the step 2.2 is specifically performed by:

calculating the average power of the amplified digital signal data according to the following formula:

；

in the formula (I), the compound is shown in the specification,the average power of the amplified digital signal data is expressed as a word length of 2aA positive integer of bits;instantaneous power of the amplified digital signal data is 2aA positive integer of bits; k represents the kth amplification operation;Nthe length of data for each operation;for the rounding function, the rounding rule is to round the integer closest to zero.

7. The method for truncating the digital signal processing word length in an antijamming receiver according to claim 4, 5 or 6, characterized in that the specific operations of step 2.3 are:

the desired power of the amplified digital signal data is calculated according to the following formula:

；

in the formula (I), the compound is shown in the specification,a desired power for the amplified digital signal data;

the specific operation of the step 3 is as follows:

calculating the difference value between the average power and the expected power of the amplified digital signal data according to the following formula:

；

in the formula (I), the compound is shown in the specification,is the difference between the average power and the desired power, and is 2aThe signed integer number of bits is the number of bits,a desired power for the amplified digital signal data;the average power of the amplified digital signal data is expressed as a word length of 2aA positive integer of bits.

8. The method according to claim 7, wherein the step 4 specifically operates as follows:

difference of average power from desired power according to k amplification operationsUpdating the gain of the amplifier in the next amplification operation, wherein the specific updating formula is as follows:

；

in the formula (I), the compound is shown in the specification,for the updated gain of the amplifier, it will be taken askThe gain value of the amplifier in +1 operation;for the gain at the k-th amplification operation of the amplifier, ofa+A 4-bit positive integer; k represents the kth amplification operation;for the rounding function, the rounding rule is to round the integer closest to zero;is the desired power of the amplified digital signal data.

9. The method of claim 8, wherein the step 5 specifically operates as follows:

intercepting the amplified digital signal dataB is a self-defined value, and the specific phase formula is as follows:

；

in the formula (I), the compound is shown in the specification,for the truncated data, isbThe signed number of bits; n is a data index number and is a positive integer; k is the number of amplification operations;Nthe length of data for each operation;for amplified digital signal data ofaThe signed number of bits;for the rounding function, the rounding rule is to round the integer closest to zero.

Technical Field

The invention belongs to the technical field of digital signal processing, and particularly relates to a digital signal processing word length truncation method in an anti-interference receiver.

Background

With the progress of digital signal processing theory and semiconductor technology, digital receivers have replaced analog receivers and are widely applied to systems such as communication, radar, navigation, audio and video processors and the like. The digital receiver is mainly characterized by a high-speed analog-to-digital converter (ADC) and a digital signal processing circuit, and has a series of advantages of high receiving sensitivity, flexible design, high stability, and the like.

In an electronic countermeasure environment, a digital receiver is required to have a certain interference resistance capability in order to cope with the threat of electromagnetic interference. Since the electromagnetic interference is a non-cooperative signal, the number and power of which generally vary with time, the level of the signal received by the receiver varies widely, typically up to tens of decibels. In order to ensure that an anti-interference receiver can still receive signals without distortion in an electronic countermeasure environment and achieve the purpose of interference suppression, an ADC of the receiver needs to have a larger conversion word length so as to improve the dynamic range of the receiver. After the interference suppression, in order to reduce the logic resource and power consumption required by the subsequent digital signal processing, the word length of the data needs to be reduced by means of truncation. For example, for a satellite navigation anti-interference receiver, the conversion word length of an ADC of the satellite navigation anti-interference receiver is generally 12-16 bits, and the data word length sent to the signal acquisition tracking module after the anti-interference processing is generally required to be truncated to 2-4 bits.

In the truncation problem of the word length in digital signal processing, it is a common practice to intercept data of a predetermined word length at a fixed position empirically, for example, when the data is truncated from 16 bits to 4 bits, the data of 4 bits higher than the fixed position is intercepted. This is a very simple way of doing this, but if the power of the data before truncation is variable, this method of truncation will cause a loss of signal to noise ratio and in severe cases will even result in the truncated data being completely unusable.

Disclosure of Invention

The invention provides a digital signal processing word length truncation method in an anti-interference receiver aiming at the requirements and defects of the prior art, and the method comprises the steps of estimating the power of data before truncation, then adaptively adjusting gain to amplify the data before truncation to a full-width state, and finally intercepting the data with a specified word length from the highest bit. Compared with the traditional method, the method is insensitive to the power change of the data before truncation, and can reduce the loss of the signal-to-noise ratio caused by truncation of the word length of the digital signal processing to the minimum.

The specific implementation content of the invention is as follows:

the invention provides a digital signal processing word length truncation method in an anti-interference receiver, which comprises the following specific operations: firstly, estimating the power of digital signal data before truncation; then, the gain is self-adaptively adjusted according to the estimated power of the digital signal data before the stage, so that the digital signal data before truncation is amplified to a full-amplitude state; and finally, intercepting data with specified word length from the highest bit in the digital signal data amplified to the full amplitude state.

In order to better implement the present invention, further, the digital signal processing word length truncation method is specifically divided into the following steps:

step 1: amplifying the acquired digital signal data using an amplifier;

step 2: calculating the average power of the amplified digital signal data;

and step 3: calculating a difference between the average power of the amplified digital signal data and the desired power;

and 4, step 4: updating the gain of the amplifier according to the difference between the calculated average power and the expected power;

and 5: data of a prescribed word length is cut out from the most significant bit of the amplified digital signal data.

In order to better implement the present invention, further, the specific operations of step 1 are:

step 1.1: setting the received digital signal data asA is a signed integer with word length of a bits, a is a self-defined value; wherein n is a data index number and is a positive integer;

step 1.2: using amplifiers for receiving digital signal dataCarrying out amplification, wherein the specific amplification formula is as follows:

；

in the formula (I), the compound is shown in the specification,for amplified digital signal data ofaThe signed number of bits;for the gain at the k-th amplification operation of the amplifier, ofa+4 bit positive integer, setting initial value of amplifierIs 2 ^a+4-1; k is the number of amplification operations;Nthe length of data for each operation;for the rounding function, the rounding rule is to round the integer closest to zero.

In order to better implement the present invention, further, the data length N of each operation is an exponential multiple of 2.

In order to better implement the present invention, further, the specific operations of step 2 are:

step 2.1: calculating the instantaneous power of the amplified digital signal data;

step 2.2: calculating the average power of the amplified digital signal data;

step 2.3: the desired power of the amplified digital signal data is calculated.

In order to better implement the present invention, further, the specific operations of step 2.1 are:

the instantaneous power of the amplified digital signal data is calculated according to the following formula:

；

in the formula (I), the compound is shown in the specification,instantaneous power of the amplified digital signal data is 2aA positive integer of bits.

In order to better implement the present invention, further, the specific operations of step 2.2 are:

calculating the average power of the amplified digital signal data according to the following formula:

；

in the formula (I), the compound is shown in the specification,the average power of the amplified digital signal data is expressed as a word length of 2aA positive integer of bits;instantaneous power of the amplified digital signal data is 2aA positive integer of bits; k represents the kth amplification operation;Nthe length of data for each operation;for the rounding function, the rounding rule is to round the integer closest to zero.

In order to better implement the present invention, further, the specific operations of step 2.3 are:

the desired power of the amplified digital signal data is calculated according to the following formula:

；

in the formula (I), the compound is shown in the specification,a desired power for the amplified digital signal data;

the specific operation of the step 3 is as follows:

calculating the difference value between the average power and the expected power of the amplified digital signal data according to the following formula:

；

in the formula (I), the compound is shown in the specification,is the difference between the average power and the desired power, and is 2aThe signed integer number of bits is the number of bits,a desired power for the amplified digital signal data;the average power of the amplified digital signal data is expressed as a word length of 2aA positive integer of bits.

In order to better implement the present invention, further, the specific operations of step 4 are:

difference of average power from desired power according to k amplification operationsUpdating the gain of the amplifier in the next amplification operation, wherein the specific updating formula is as follows:

；

in the formula (I), the compound is shown in the specification,for the updated gain of the amplifier, it will be taken askThe gain value of the amplifier in +1 operation;for the gain at the k-th amplification operation of the amplifier, ofa+A 4-bit positive integer; k represents the kth amplification operation;for the rounding function, the rounding rule is to round the integer closest to zero;is the desired power of the amplified digital signal data.

In order to better implement the present invention, further, the specific operations of step 5 are:

intercepting the amplified digital signal dataB is a self-defined value, and the specific phase formula is as follows:

；

in the formula (I), the compound is shown in the specification,for the truncated data, isbThe signed number of bits; n is a data index number and is a positive integer; k is the number of amplification operations;Nthe length of data for each operation;for amplified digital signal data ofaSigned of bitCounting;for the rounding function, the rounding rule is to round the integer closest to zero.

Compared with the prior art, the invention has the following advantages and beneficial effects:

the invention adaptively amplifies the data before truncation to a full-width state and intercepts the data with the specified word length from the highest bit, thereby overcoming the problems of sensitivity to data power and overlarge truncation loss in the prior art and reducing the signal-to-noise ratio loss caused by truncation of the word length processed by the digital signal to the minimum.

Drawings

FIG. 1 is a flow chart of a digital signal processing word length truncation method in an anti-interference receiver provided by the invention;

FIG. 2 is a time domain envelope diagram of data obtained by the method of the present invention before word length truncation of digital signal processing;

FIG. 3 is a time domain envelope plot of data obtained by the method of the present invention after word length truncation of digital signal processing;

FIG. 4 is a graph of the gain of an amplifier obtained by the method of the present invention;

fig. 5 is a time-domain envelope diagram of data processed by a conventional method and cut off in word length.

Detailed Description

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and therefore should not be considered as a limitation to the scope of protection. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Example 1:

the embodiment provides a digital signal processing word length truncation method in an anti-interference receiver, which specifically comprises the following operations: firstly, estimating the power of digital signal data before truncation; then, the gain is self-adaptively adjusted according to the estimated power of the digital signal data before the stage, so that the digital signal data before truncation is amplified to a full-amplitude state; and finally, intercepting data with specified word length from the highest bit in the digital signal data amplified to the full amplitude state. The invention overcomes the problems of sensitivity to data power and overlarge truncation loss in the prior art, and can reduce the signal-to-noise ratio loss caused by truncation of the digital signal processing word length to the minimum.

Example 2:

on the basis of the foregoing embodiment 1, as shown in fig. 1, in order to better implement the present invention, further, the digital signal processing word length truncation method includes the following steps:

step 1: amplifying the acquired digital signal data using an amplifier;

step 2: calculating the average power of the amplified digital signal data;

and step 3: calculating a difference between the average power of the amplified digital signal data and the desired power;

and 4, step 4: updating the gain of the amplifier according to the difference between the calculated average power and the expected power;

and 5: data of a prescribed word length is cut out from the most significant bit of the amplified digital signal data.

Other parts of this embodiment are the same as those of embodiment 1, and thus are not described again.

Example 3:

in this embodiment, on the basis of any one of the above embodiments 1-2, in order to better implement the present invention, further, the specific operations of step 1 are as follows:

step 1.1: setting the received digital signal data asA is a signed integer with word length of a bits, a is a self-defined value; wherein n is a data index number and is a positive integer;

step 1.2: using amplifiers for receiving digital signal dataCarrying out amplification, wherein the specific amplification formula is as follows:

；

in the formula (I), the compound is shown in the specification,for amplified digital signal data ofaThe signed number of bits;for the gain at the k-th amplification operation of the amplifier, ofa+4 bit positive integer, setting initial value of amplifierIs 2 ^a+4-1; k is the number of amplification operations;Nthe data length of each operation is generally exponential times of 2, such as 1024, 2048 and the like;for the rounding function, the rounding rule is to round the integer closest to zero.

Other parts of this embodiment are the same as any of embodiments 1-2 described above, and thus are not described again.

Example 4:

in this embodiment, on the basis of any one of the above embodiments 1 to 3, in order to better implement the present invention, further, the specific operation of step 2 is:

step 2.1: calculating the instantaneous power of the amplified digital signal data;

step 2.2: calculating the average power of the amplified digital signal data;

step 2.3: the desired power of the amplified digital signal data is calculated.

Further, the specific operation of step 2.1 is as follows:

the instantaneous power of the amplified digital signal data is calculated according to the following formula:

；

in the formula (I), the compound is shown in the specification,instantaneous power of the amplified digital signal data is 2aA positive integer of bits.

Further, the specific operation of step 2.2 is:

calculating the average power of the amplified digital signal data according to the following formula:

；

in the formula (I), the compound is shown in the specification,the average power of the amplified digital signal data is expressed as a word length of 2aA positive integer of bits;instantaneous power of the amplified digital signal data is 2aA positive integer of bits; k represents the kth amplification operation;Nthe length of data for each operation;for the rounding function, the rounding rule is to round the integer closest to zero.

Further, the specific operation of step 2.3 is:

the desired power of the amplified digital signal data is calculated according to the following formula:

；

in the formula (I), the compound is shown in the specification,is the desired power of the amplified digital signal data.

Other parts of this embodiment are the same as any of embodiments 1 to 3, and thus are not described again.

Example 5:

in this embodiment, on the basis of any one of the above embodiments 1 to 4, in order to better implement the present invention, further, the specific operation of step 3 is:

calculating the difference value between the average power and the expected power of the amplified digital signal data according to the following formula:

；

in the formula (I), the compound is shown in the specification,is the difference between the average power and the desired power, and is 2aThe signed integer number of bits is the number of bits,a desired power for the amplified digital signal data;representing the number of amplified digital signalsAccording to the average power, the word length is 2aA positive integer of bits.

Other parts of this embodiment are the same as any of embodiments 1 to 4, and thus are not described again.

Example 6:

in this embodiment, on the basis of any one of the above embodiments 1 to 5, in order to better implement the present invention, further, the specific operation of step 4 is:

difference of average power from desired power according to k amplification operationsUpdating the gain of the amplifier in the next amplification operation, wherein the specific updating formula is as follows:

；

in the formula (I), the compound is shown in the specification,for the updated gain of the amplifier, it will be taken askThe gain value of the amplifier in +1 operation;for the gain at the k-th amplification operation of the amplifier, ofa+A 4-bit positive integer; k represents the kth amplification operation;for the rounding function, the rounding rule is to round the integer closest to zero;is the desired power of the amplified digital signal data.

Other parts of this embodiment are the same as any of embodiments 1 to 5, and thus are not described again.

Example 7:

in this embodiment, on the basis of any one of the above embodiments 1 to 6, in order to better implement the present invention, further, the specific operation of step 5 is:

intercepting the amplified digital signal dataB is a self-defined value, and the specific phase formula is as follows:

；

in the formula (I), the compound is shown in the specification,for the truncated data, isbThe signed number of bits; n is a data index number and is a positive integer; k is the number of amplification operations;Nthe length of data for each operation;for amplified digital signal data ofaThe signed number of bits;for the rounding function, the rounding rule is to round the integer closest to zero.

Other parts of this embodiment are the same as any of embodiments 1 to 6, and thus are not described again.

Example 8:

this embodiment is based on any of embodiments 1 to 7, as shown in fig. 2, 3, 4, and 5: fig. 2 and fig. 3 are time domain envelope diagrams of data before and after word length truncation of digital signal processing obtained by the method of the present invention. In this embodiment, the data before word length truncation of the interference-free receiver is a 16-bit signed integer, and the data needs to be truncated to 4 bits. The data length N of each operation is 1024, which is totally 1000 times, and as can be seen from fig. 2, the envelope of the data before word length truncation has obvious fluctuation, which indicates that the power of the data is changed. As can be seen from fig. 3, the envelope of the data after word length truncation is substantially constant and in a full-width state after being processed by the method of the present invention. Fig. 4 shows the gain value of the amplifier obtained by the method of the present invention, the gain value is a 20-bit positive integer, the initial value is set to 220-1, and it can be seen from the figure that the gain value of the amplifier is small when the data envelope is large before truncation, and is large when the envelope is small, so that the amplified data envelope can be kept constant.

Further, fig. 5 shows the data obtained after the word length truncation by the conventional method (truncating 4 bits), and it can be seen that the data envelope still has fluctuation and the storage word length of 4 bits is not fully utilized. According to the experimental result, in the embodiment, after the processing by the method of the invention, the signal-to-noise ratio loss caused by word length truncation is 0.22dB, which is much lower than 5.96dB of the traditional method, and the method has obvious advantages.

Other parts of this embodiment are the same as any of embodiments 1 to 7, and thus are not described again.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and all simple modifications and equivalent variations of the above embodiments according to the technical spirit of the present invention are included in the scope of the present invention.