CN103684339B - The filtering method of suppression arrowband single tone jamming - Google Patents

Abstract

The present invention proposes a kind of filtering method suppressing arrowband single tone jamming and device, said method comprising the steps of: step S1:Notch wave filter reads the index value of the iterative filter factor of this filter time domain according to the difference of carrier signal mid frequency Yu arrowband single-tone interference frequency；Step S2:Notch wave filter reads, according to described index value, the filter factor that this filter time domain is iterative；Step S3:Notch wave filter is iterative according to time domain and filter factor calculates and is filtered described carrier signal and exports filter result.The present invention suppresses the filtering method of arrowband single tone jamming and device to read index value by Notch wave filter according to the difference of carrier signal mid frequency with arrowband single-tone interference frequency, and the iterative filter factor of the filter time domain corresponding with this index value thus be filtered, its design is simple, filter effect is preferable, very practical.

Description

The filtering method of suppression arrowband single tone jamming

Technical field

The present invention relates to communication technical field, particularly to a kind of filtering method suppressing arrowband single tone jamming and device.

Background technology

In communication process, due to a variety of causes, often have some voltages unrelated with measured signal or electric current exists, so can affect performance and the quality of communication data.These signals are called interference, and it is divided into internal interference and external disturbance.

Internal interference, is interfering with each other between the internal each parts of communication system, and this interference by the appropriate design of communicator, the rational deployment of parts, or can take quarantine measures etc. eliminated or weaken.

External disturbance, is to be produced by the factor outside communication system, and common interference includes:

1, mechanical disturbance

Mechanical disturbance is the most serious, the most extensive.Mechanical vibration can make wire move in magnetic field, produces induction electromotive force.Suppress this kind of interference, with vibration reducing measure, as used shock-absorbing spring or vibration isolation rubber etc..

2, temperature interference

Owing to temperature is too high, fluctuation and uneven, temperature often results in electronic component Parameters variation or produces thermoelectrical potential in the detection, thus measurement result is caused severe jamming.In engineering, general employing heat shielding method suppression heat interference, as loaded sensing element in calorstat.In electronic measuring device, frequently with temperature-compensating measure, with the compensates impact on testing result.

3, electromagnetic interference

Due to the existence of the stray EM field such as electromotor, motor and gas discharge device, electric field or the change in magnetic field in factories and miness, the interference of electric or magnetic can be made to enter in electronic measuring device, cause interference signal.

In existing communication system, time domain launches signal can be mixed into arrowband single tone jamming after channel, and this arrowband single tone jamming is complex exponential form:

$i_l\left(t\right)=A_0{e}^{j{\mathrm{\φ}}_0}{e}^{j2\mathrm{\π}{f}_0(t+t_l)},$

Wherein, A₀For the amplitude of single tone jamming, φ₀For the initial phase of single tone jamming, f₀Frequency for known single tone jamming.

After being mixed into the time-domain signal arrival receiving terminal of single tone jamming, need to be filtered this arrowband single tone jamming processing, it is typically to add filter module and realizes Suppression of narrow band interference function, but the filtration module added generally is only capable of being filtered specific single interference, poor effect.

Summary of the invention

The purpose of the present invention is to propose to a kind of design filtering method simple, that effect preferably suppresses arrowband single tone jamming.

For reaching above-mentioned purpose, the present invention proposes a kind of filtering method suppressing arrowband single tone jamming, comprises the following steps:

Step S1:Notch wave filter reads the index value of the iterative filter factor of this filter time domain according to the difference of carrier signal mid frequency Yu arrowband single-tone interference frequency；

Step S2:Notch wave filter reads, according to described index value, the filter factor that this filter time domain is iterative；

Step S3:Notch wave filter is iterative according to time domain and filter factor calculates and is filtered described carrier signal and exports filter result.

Further, in the filtering method of above-mentioned suppression arrowband single tone jamming, also include before described step S1: Notch wave filter reinitializes before every frame filters.

Further, in the filtering method of above-mentioned suppression arrowband single tone jamming, also include before described step S1:

According to the difference of carrier signal mid frequency Yu arrowband single-tone interference frequency, store the index value that this difference filter factor iterative with this filter time domain is corresponding.

Further, in the filtering method of above-mentioned suppression arrowband single tone jamming, described step S2 specifically includes:

Step S201:Notch wave filter obtains the storage address of the iterative filter factor of this filter time domain according to described index value, and described index value exists, with the storage address of this filter factor, a kind of corresponding relation mapped one by one；

Step S202:Notch wave filter reads, according to described storage address, the filter factor that this filter time domain is iterative.

Further, in the filtering method of above-mentioned suppression arrowband single tone jamming, the filter factor storage of described Notch wave filter uses ROM, the ROM degree of depth to be 64, and data bit width is 96bit.

Separately, the present invention provides a kind of filter suppressing arrowband single tone jamming, including:

Index value reads unit, reads the index value of the iterative filter factor of this filter time domain according to the difference of carrier signal mid frequency Yu arrowband single-tone interference frequency for Notch wave filter；

Filter factor reads unit, reads, according to described index value, the filter factor that this filter time domain is iterative for Notch wave filter；And

Filtering computing unit, and filter factor iterative according to time domain for Notch wave filter calculates and is filtered described carrier signal and exports filter result.

Further, in the filter of above-mentioned suppression arrowband single tone jamming, described filter also includes initialization unit, reinitializes before every frame filters for Notch wave filter.

Further, in the filter of above-mentioned suppression arrowband single tone jamming, described filter also includes index value memory element, for the difference according to carrier signal mid frequency Yu arrowband single-tone interference frequency, stores the index value that this difference filter factor iterative with this filter time domain is corresponding.

Further, in the filter of above-mentioned suppression arrowband single tone jamming, described filter factor reads unit and farther includes:

Storage address subelement, obtains the storage address of the iterative filter factor of this filter time domain for Notch wave filter according to described index value, and described index value exists, with the storage address of this filter factor, a kind of corresponding relation mapped one by one；And

Filter factor subelement, reads, according to described storage address, the filter factor that this filter time domain is iterative for Notch wave filter.

Further, in the filter of above-mentioned suppression arrowband single tone jamming, the filter factor storage of described Notch wave filter uses ROM, the ROM degree of depth to be 64, and data bit width is 96bit.

The present invention suppresses the filtering method of arrowband single tone jamming and device to read index value by Notch wave filter according to the difference of carrier signal mid frequency with arrowband single-tone interference frequency, and the iterative filter factor of the filter time domain corresponding with this index value thus be filtered, its design is simple, filter effect is preferable, very practical.

Accompanying drawing explanation

Fig. 1 is the schematic flow sheet that the present invention suppresses filtering method one embodiment of arrowband single tone jamming；

Fig. 2 is difference and the index value corresponding relation structural representation of centre carrier frequency and arrowband single-tone interference frequency；

Fig. 3 is the idiographic flow schematic diagram of Fig. 1 step S2；

Fig. 4 is to calculate the structural representation that complex multiplication realizes in Fig. 1 step S3；

Fig. 5 is the structural representation that the present invention suppresses filter one embodiment of arrowband single tone jamming.

Detailed description of the invention

Describe the preferred embodiments of the present invention below in conjunction with the accompanying drawings in detail.

The present invention suppresses the filtering method of arrowband single tone jamming to use Notch wave filter to be filtered, and this Notch wave filter can only have a zero point on unit circle.Realizing cost to reduce, use first order IIR Notch wave filter effectively to suppress arrowband single tone jamming, the system function of this Notch wave filter is:

$\frac{\frac{1-j\tan \left(\frac{{\mathrm{\ω}}_0}{2}\right)}{1+\frac{\tan \left(\frac{B_{\mathrm{\ω}}}{2}\right)}{1+\cos \left({\mathrm{\ω}}_0\right)}-j\tan \left(\frac{{\mathrm{\ω}}_0}{2}\right)\sqrt{1-\frac{{\tan }^2\left(\frac{B_{\mathrm{\ω}}}{2}\right)}{{\sin }^2{\mathrm{\ω}}_0}}}-\frac{1+j\tan \left(\frac{{\mathrm{\ω}}_0}{2}\right)}{1+\frac{\tan \left(\frac{B_{\mathrm{\ω}}}{2}\right)}{1+\cos \left({\mathrm{\ω}}_0\right)}-j\tan \left(\frac{{\mathrm{\ω}}_0}{2}\right)\sqrt{1-\frac{{\tan }^2\left(\frac{B_{\mathrm{\ω}}}{2}\right)}{{\sin }^2{\mathrm{\ω}}_0}}}{z}^{-1}}{1-\frac{1-\frac{\tan \left(\frac{B_{\mathrm{\ω}}}{2}\right)}{1+\cos \left({\mathrm{\ω}}_0\right)}+j\tan \left(\frac{{\mathrm{\ω}}_0}{2}\right)\sqrt{1-\frac{{\tan }^2\left(\frac{B_{\mathrm{\ω}}}{2}\right)}{{\sin }^2{\mathrm{\ω}}_0}}}{1+\frac{\tan \left(\frac{B_{\mathrm{\ω}}}{2}\right)}{1+\cos \left({\mathrm{\ω}}_0\right)}-j\tan \left(\frac{{\mathrm{\ω}}_0}{2}\right)\sqrt{1-\frac{{\tan }^2\left(\frac{B_{\mathrm{\ω}}}{2}\right)}{{\sin }^2{\mathrm{\ω}}_0}}}{z}^{-1}}$

Wherein, ω₀=2 π f₀/F_sFor numeral Notch angular frequency, B_ω=2 π B/F_s, B is 3-dBNotch bandwidth, and Fs is sample frequency.

Referring to Fig. 1, the present invention suppresses the filtering method of arrowband single tone jamming to comprise the following steps:

Step S1:Notch wave filter reads the index value of the iterative filter factor of this filter time domain according to the difference of carrier signal mid frequency Yu arrowband single-tone interference frequency；

Step S2:Notch wave filter reads, according to described index value, the filter factor that this filter time domain is iterative；

Step S3:Notch wave filter is iterative according to time domain and filter factor calculates and is filtered described carrier signal and exports filter result.

The present invention suppresses the filtering method of arrowband single tone jamming to use Notch wave filter, and its time domain is iterative is:

Y (n)=α₁y(n-1)+β₀x(n)+β₁x(n-1)(1)

Wherein, α, β₀, β₁Filter factor for Notch wave filter.

When realizing, different from the difference of arrowband single-tone interference frequency according to carrier signal mid frequency, this Notch wave filter selects different filter factors to be filtered.

Also include before described step S1: Notch wave filter reinitializes before every frame filters.

Notch wave filter is filtered in units of frame, and every frame starts, and Notch wave filter is required for reinitializing (y (n)=0), i.e. uses reception reset signal to reset wave filter.Every frame has all initialized a benefit, can ignore the error accumulation problem that iir filter is intrinsic.

From formula (1), Notch wave filter has three complex coefficients (i.e. filter factor), this communication system is when centre carrier frequency is identical with arrowband single-tone interference frequency, receptivity will not be affected, without carrying out Notch filtering, but in order to ensure system signal uniformity for the treatment of, being also carried out Filtering Processing in the case of being somebody's turn to do, filter coefficient takes α₁=0, β₀=1, β₁=0, this filter coefficient uses Q15 calibration, then 16 ' h7FFF represent 1 (the filter factor fixed point of floating number will be multiplied by 2 by filter factor¹⁵After round, use 16bit binary number representation).

If during this communication system configuration carrier signal mid frequency, step value is 25KHz.Assume that system exists 51 kinds of different filter factors combination situations and (includes that filter factor is α₁=0, β₀=1, β₁The situation of=0).The bit wide of wave filter complex coefficient real part and imaginary part is 16bit, then filter coefficient needs the memory space of 51*3* (16+16) bit=612Byte altogether.

The filter factor storage of this wave filter uses ROM, the ROM degree of depth to be 64, and data bit width is 96bit.In three complex coefficients ROM of wave filter, storage mode is:

d95-d80α₁Real part, d79-d64 α₁Imaginary part；d63-d48β₀Real part, d47-d32 β₀Imaginary part；d31-d16β₁Real part, d15-d0 β₁Imaginary part.(after the real part of the filter factor of this wave filter and imaginary part use Q15 calibration, bit wide is 16bit)

Refer to difference and index value corresponding relation structural representation that Fig. 2, Fig. 2 are centre carrier frequency and arrowband single-tone interference frequency.Also include before described step S1:

According to the difference of carrier signal mid frequency Yu arrowband single-tone interference frequency, store the index value that this difference filter factor iterative with this filter time domain is corresponding.

During the work of this communication system, according to centre carrier frequency f and arrowband single-tone interference frequency f₀Difference (Δ f=f-f₀) read index (Index) value.

Referring to Fig. 3, described step S2 specifically includes:

Step S201:Notch wave filter obtains the storage address of the iterative filter factor of this filter time domain according to described index value, and described index value exists, with the storage address of this filter factor, a kind of corresponding relation mapped one by one；

For different communication systems, it is inconsistent that the Notch wave filter that system suppression arrowband single tone jamming uses exists different filter factor combination quantity, i.e. index value Index is inconsistent, and it is the most inconsistent that three complex coefficients of wave filter (i.e. filter factor) stores address (rom_address) in ROM.But there is the corresponding relation mapped one by one between this storage address rom_address and index value Index, i.e. concrete mapping relations.

Step S202:Notch wave filter reads, according to described storage address, the filter factor that this filter time domain is iterative.

As shown in table 1, Notch wave filter can read three complex coefficients α of wave filter, β according to described storage address from ROM₀, β₁, complete the selection to filter coefficient.

Three complex coefficients of table 1Notch wave filter store corresponding table in ROM

In described step S3, Notch wave filter is obtaining filter coefficient alpha, β₀, β₁After, substituted into

Formula (1) y (n)=α₁y(n-1)+β₀x(n)+β₁X (n-1) carries out computing, wherein, is first respectively completed α₁Y (n-1), β₀X (n), β₁The complex multiplication operation of x (n-1).

Complex multiplication operation process can be represented by the formula:

C_i+jC_q=(A_i+jA_q)*(B_i+jB_q)=(A_iB_i-A_qB_q)+j(A_iB_q+A_qB_i)(2)

Be can be seen that a complex multiplication needs four multiplication, a sub-addition and a subtraction by formula (2).Implementing employing adder and multiplier and subtract device with taking advantage of, complex multiplication operation result is DATA_OUT_I [31:0], DATA_OUT_Q [31:0].Filter factor uses Q15 calibration, then after complex multiplication operation, the output of IQ takes multiplication DATA_OUT_I [30:15], DATA_OUT_Q [30:15].

Implement structure as shown in Figure 4, α₁Y (n-1), β₀X (n), β₁The output data of the complex multiplication computing respectively of x (n-1) divide real part (high 16bit) and imaginary part (low 16bit) data to carry out additive operation respectively again.The result output of additive operation can realize suppressing arrowband single tone jamming function.

Refer to Fig. 5, the present invention also provides for a kind of filter suppressing arrowband single tone jamming, read unit 10 including index value, filter factor reads unit 20 and filtering computing unit 30, and described index value reads unit 10 and reads the index value of the iterative filter factor of this filter time domain for Notch wave filter according to the difference of carrier signal mid frequency Yu arrowband single-tone interference frequency；Described filter factor reads unit 20, reads, according to described index value, the filter factor that this filter time domain is iterative for Notch wave filter；Described filtering computing unit 30 is iterative according to time domain for Notch wave filter and filter factor calculates and is filtered described carrier signal and exports filter result.

Wherein, the present invention suppresses the filtering method of arrowband single tone jamming to use Notch wave filter, and its time domain is iterative is:

Y (n)=α₁y(n-1)+β₀x(n)+β₁x(n-1)(1)

When realizing, different from the difference of arrowband single-tone interference frequency according to carrier signal mid frequency, this Notch wave filter selects different filter factors to be filtered.

Described filter also includes initialization unit 40, reinitializes before every frame filters for Notch wave filter.

Notch wave filter is filtered in units of frame, and every frame starts, and Notch wave filter is required for reinitializing (y (n)=0), i.e. uses reception reset signal to reset wave filter.Every frame has all initialized a benefit, can ignore the error accumulation problem that iir filter is intrinsic.

From formula (1), Notch wave filter has three complex coefficients (i.e. filter factor), this communication system is when centre carrier frequency is identical with arrowband single-tone interference frequency, receptivity will not be affected, without carrying out Notch filtering, but in order to ensure system signal uniformity for the treatment of, being also carried out Filtering Processing in the case of being somebody's turn to do, filter coefficient takes α₁=0, β₀=1, β₁=0 (this filter coefficient uses Q15 calibration, then 16 ' h7FFF represent 1).

If during this communication system configuration carrier signal mid frequency, step value is 25KHz.Assume that system exists 51 kinds of different filter factors combination situations and (includes that filter factor is α₁=0, β₀=1, β₁The situation of=0).The bit wide of wave filter complex coefficient real part and imaginary part is 16bit, then filter coefficient needs the memory space of 51*3* (16+16) bit=612Byte altogether.

The filter factor storage of this Notch wave filter uses ROM, the ROM degree of depth to be 64, and data bit width is 96bit.In three complex coefficients ROM of wave filter, storage mode is:

d95-d80α₁Real part, d79-d64 α₁Imaginary part；d63-d48β₀Real part, d47-d32 β₀Imaginary part；d31-d16β₁Real part, d15-d0 β₁Imaginary part.

Described filter also includes index value memory element 50, for the difference according to carrier signal mid frequency Yu arrowband single-tone interference frequency, stores the index value that this difference filter factor iterative with this filter time domain is corresponding.

Described filter factor reads unit 20 and farther includes to store address subelement 202 and filter factor subelement 204, described storage address subelement 202 obtains the storage address of the iterative filter factor of this filter time domain for Notch wave filter according to described index value, and described index value exists, with the storage address of this filter factor, a kind of corresponding relation mapped one by one；Described filter factor subelement 204 reads, according to described storage address, the filter factor that this filter time domain is iterative for Notch wave filter.

Compared to prior art, the present invention suppresses the filtering method of arrowband single tone jamming and device to read index value by Notch wave filter according to the difference of carrier signal mid frequency with arrowband single-tone interference frequency, and the iterative filter factor of the filter time domain corresponding with this index value thus be filtered, its design is simple, filter effect is preferable, very practical.

Here description of the invention and application is illustrative, is not wishing to limit the scope of the invention in above-described embodiment.The deformation of embodiments disclosed herein and change are possible, and for those skilled in the art, embodiment is replaced and the various parts of equivalence are known.It should be appreciated by the person skilled in the art that in the case of without departing from the spirit or essential characteristics of the present invention, the present invention can in other forms, structure, layout, ratio, and realize with other assembly, material and parts.In the case of without departing from scope and spirit of the present invention, embodiments disclosed herein can be carried out other deformation and change.

Claims (4)

1. the filtering method suppressing arrowband single tone jamming, it is characterised in that comprise the following steps:

Step S1:Notch wave filter reads the index value of the iterative filter factor of this filter time domain according to the difference of carrier signal mid frequency Yu arrowband single-tone interference frequency；

Step S2:Notch wave filter reads, according to described index value, the filter factor that this filter time domain is iterative；

Step S3:Notch wave filter is iterative according to time domain and filter factor calculates and is filtered described carrier signal and exports filter result；

Also include before described step S1: Notch wave filter reinitializes before every frame filters；

Also include before described step S1:

According to the difference of carrier signal mid frequency Yu arrowband single-tone interference frequency, store the index value that this difference filter factor iterative with this filter time domain is corresponding；

Described step S2 specifically includes:

Step S201:Notch wave filter obtains the storage address of the iterative filter factor of this filter time domain according to described index value, and described index value exists, with the storage address of this filter factor, a kind of corresponding relation mapped one by one；

Step S202:Notch wave filter reads, according to described storage address, the filter factor that this filter time domain is iterative.

The filtering method of suppression arrowband the most according to claim 1 single tone jamming, it is characterised in that the filter factor storage of described Notch wave filter uses ROM, the ROM degree of depth to be 64, and data bit width is 96bit.

3. the filter suppressing arrowband single tone jamming, it is characterised in that including:

Index value reads unit, reads the index value of the iterative filter factor of this filter time domain according to the difference of carrier signal mid frequency Yu arrowband single-tone interference frequency for Notch wave filter；

Filter factor reads unit, reads, according to described index value, the filter factor that this filter time domain is iterative for Notch wave filter；And

Filtering computing unit, and filter factor iterative according to time domain for Notch wave filter calculates and is filtered described carrier signal and exports filter result；Described filter also includes initialization unit, reinitializes before every frame filters for Notch wave filter；

Described filter also includes index value memory element, for the difference according to carrier signal mid frequency Yu arrowband single-tone interference frequency, stores the index value that this difference filter factor iterative with this filter time domain is corresponding；

Described filter factor reads unit and farther includes:

Storage address subelement, obtains the storage address of the iterative filter factor of this filter time domain for Notch wave filter according to described index value, and described index value exists, with the storage address of this filter factor, a kind of corresponding relation mapped one by one；And

Filter factor subelement, reads, according to described storage address, the filter factor that this filter time domain is iterative for Notch wave filter.

The filter of suppression arrowband the most according to claim 3 single tone jamming, it is characterised in that the filter factor storage of described Notch wave filter uses ROM, the ROM degree of depth to be 64, and data bit width is 96bit.