阅读说明：本技术 一种阶数与类型皆可重构的滤波器 (Filter with reconfigurable order and type ) 是由 刘新宁 陈超 于 2021-01-26 设计创作，主要内容包括：本发明公开了一种阶数与类型皆可重构的滤波器,包括I路信号通道和Q路信号通道,交叉藕合电路以及控制逻辑,I路信号超前Q路信号90度,通过交叉耦合电路连接实现频谱搬移,控制逻辑产生控制信号实现中频的可调节。I路信号通道和Q路信号通道中的开关切换可以实现滤波器阶数与类型的转换,以满足不同的需求。本发明不采用传统的固定阻值的交叉耦合电阻,能够有效的避免因极端工艺角下出现的电阻变化,导致的中频频率偏移,流片后的芯片良率差的问题,而且本发明可以作为一阶或者二阶的基本单元,对其进行级联以更高阶的中频可控的带通或低通滤波器,相比较同类滤波器此架构功耗也较低。(The invention discloses a filter with reconfigurable orders and types, which comprises an I-path signal channel, a Q-path signal channel, a cross coupling circuit and control logic, wherein the I-path signal leads the Q-path signal by 90 degrees, the frequency spectrum shifting is realized through the connection of the cross coupling circuit, and the control logic generates a control signal to realize the adjustment of intermediate frequency. The switching of the switches in the I-path signal channel and the Q-path signal channel can realize the conversion of the order and the type of the filter so as to meet different requirements. The invention does not adopt the traditional cross coupling resistor with fixed resistance value, can effectively avoid the problems of intermediate frequency shift and poor chip yield after chip flow caused by resistance change under extreme process angles, can be used as a first-order or second-order basic unit, can be cascaded to form a higher-order intermediate frequency controllable band-pass or low-pass filter, and has lower power consumption compared with the similar filter.)

1. A filter having reconfigurable order and type, comprising: comprises an I-path signal channel, a Q-path signal channel, a cross coupling circuit,

the I path signal channel and the Q path signal channel are used for realizing second-order low-pass filtering;

and the cross coupling circuit is used for connecting the control signal generated by the peripheral control logic for realizing frequency spectrum shifting to control the cross coupling circuit and realize the adjustment of the intermediate frequency.

2. A filter of claim 1, wherein the filter is reconfigurable in both order and type: the I-path signal channel comprises a positive input end (Vin _ I +) of a first radio-frequency signal I-path, a negative input end (Vin _ I-) of the first radio-frequency signal I-path, a first resistor (Rl), a second resistor (R2), a third resistor (R3), a fourth resistor (R4), a fifth resistor (R5), a sixth resistor (R6), a seventh resistor (R7), an eighth resistor (R8), a first capacitor (Cl), a second capacitor (C2), a third capacitor (C3), a first operational amplifier, a positive output end (Vout _ I +) of the first radio-frequency signal I-path, and a negative input end (Vin _ I-) of the first radio-frequency signal I-path;

the radio frequency signal I circuit comprises a positive input end (Vin _ I +) of a first radio frequency signal I circuit, a first resistor (Rl), a second resistor (R2), a first capacitor (Cl) and a fourth resistor (R4), wherein the positive input end (Vin _ I +) of the first radio frequency signal I circuit is connected with one end of the first resistor (Rl), the other end of the first resistor (Rl) is respectively connected with one end of the second resistor (R2), the positive end of the first capacitor (Cl) and one end of the fourth resistor (R4), the other end of the fourth resistor (R4) is connected with one end of a third switch (S3), the other end of the third switch (S3) is connected with a positive output end of a first operational amplifier, and the; the negative end of a second capacitor (C2) is respectively connected with the negative output end of the first operational amplifier and one end of a third resistor (R3), and the positive end of a second capacitor (C2) is respectively connected with the positive input end of the first operational amplifier and one end of a third resistor (R3); the negative output end of the first operational amplifier is the negative output end (Vout _ I-) of the first radio-frequency signal I way, and the positive output end of the first operational amplifier is the positive output end (Vout _ I +) of the first radio-frequency signal I way; the negative input end (Vin _ I-) of the first radio frequency signal I path is connected with one end of a sixth resistor (R6), and the other end of the sixth resistor (R6) is respectively connected with one end of a seventh resistor (R7), one end of a first switch (Sl) and one end of a fifth resistor (R5); the other end of the first switch (S1) is connected with the negative end of the first capacitor (C1), and the other end of the fifth resistor (R5) is connected with one end of the fourth switch (S4); the other end of the fourth switch (S4) is connected with the output negative end of the first operational amplifier, the other end of the seventh resistor (R7) is respectively connected with the anode of the third capacitor (C3), and one end of the eighth resistor (R8) is connected with the negative input end of the first operational amplifier; the other end of the eighth resistor (R8) is respectively connected with the anode output end of the second operational amplifier and the negative end of the third capacitor (C3).

3. A filter of claim 1, wherein the filter is reconfigurable in both order and type: the Q-path signal channel comprises a positive input end (Vin _ Q +) of a second radio-frequency signal Q-path, a negative output end (Vout _ Q-) of a first radio-frequency signal Q-path, a ninth resistor (R9), a tenth resistor (R10), an eleventh resistor (R11), a twelfth resistor (R12), a thirteenth resistor (R13), a fourteenth resistor (R14), a fifteenth resistor (R15), a sixteenth resistor (R16), a fourth capacitor (C4), a fifth capacitor (C5), a sixth capacitor (C6), a second operational amplifier, a positive output end (Vout _ Q +) of the first radio-frequency signal Q-path and a negative input end (Vin _ Q-) of the second radio-frequency signal Q-path;

the positive input end (Vin _ Q +) of the second radio-frequency signal Q way is connected with one end of a ninth resistor (R9), the other end of the ninth resistor (R9) is respectively connected with one end of a tenth resistor (R10), the positive end of a fourth capacitor (C4) and one end of a twelfth resistor (R12), the other end of the twelfth resistor (R12) is connected with one end of a fifth switch (S5), and the other end of the fifth switch (S5) is connected with the positive output end of the second operational amplifier; the other end of the tenth resistor (R10) is respectively connected with the input positive end of the second operational amplifier and the positive end of the fifth capacitor; the negative end of a fifth capacitor (C5) is respectively connected with the output negative end of a second operational amplifier and one end of an eleventh resistor (R11), the positive end of a fifth capacitor (C5) is respectively connected with the input positive end of the second operational amplifier and one end of an eleventh resistor (R11), the output negative end of the second operational amplifier is the negative output end (Vout _ Q-) of a first radio-frequency signal Q-way, the output positive end of the second operational amplifier is the output positive electrode (Vout _ Q +) of a first radio-frequency signal Q-way, the negative input end (Vin _ Q-) of a second radio-frequency signal Q-way is connected with one end of a fourteenth resistor (R14), the other end of the fourteenth resistor (R14) is respectively connected with one end of a fifteenth resistor (R15), one end of a thirteenth resistor (R13) and one end of a second switch (S2), the other end of the second switch (S2) is connected with the negative end of a fourth capacitor (C4), the other end of the thirteenth resistor (R13) is connected with one end of a sixth switch (S6), the other end of the sixth switch (S6) is connected with the negative output end of the second operational amplifier; the other end of the fifteenth resistor (R15) is respectively connected with the anode of the sixth capacitor (C6), one end of the sixteenth resistor (R16) is connected with the cathode input end of the second operational amplifier, and the other end of the sixteenth resistor (R16) is respectively connected with the anode output end of the second operational amplifier and the cathode of the sixth capacitor (C6).

4. A filter of claim 3 having reconfigurable order and type, wherein: the cross-coupling circuit includes a first cross-coupling module (T1), a second cross-coupling module (T2), a second cross-coupling module (T3), a second cross-coupling module (T4), and control logic;

one end of the first cross-coupling module (T1) is connected to one end of a seventh switch (S7), the other end of the seventh switch (S7) is connected to the positive input end of the first operational amplifier, the other end of the first cross-coupling module (T1) is connected to the negative output end of the second operational amplifier, one end of the second cross-coupling module (T2) is connected to one end of an eighth switch (S8), the other end of the eighth switch (S8) is connected to the negative input end of the first operational amplifier, and the other end of the second cross-coupling module (T2) is connected to the positive output end of the second operational amplifier; one end of a third cross coupling module (T3) is connected with one end of a ninth switch (S9), the other end of the ninth switch (S9) is connected with the positive electrode output end of the first operational amplifier, the other end of the third cross coupling module (T3) is connected with the positive electrode input end of the second operational amplifier, one end of a fourth cross coupling module (T4) is connected with one end of a tenth switch (S10), the other end of the tenth switch (S10) is connected with the negative electrode output end of the first operational amplifier, the other end of the fourth cross coupling module (T4) is connected with the positive input end of the second operational amplifier, the four cross coupling circuits have the same structure, and control signals S1-Sn generated by control logic are respectively connected with the grids of M1-Mn; the source of M1-Mn is connected with one end of R1-Rn; the Rconstant resistors are respectively connected with the drain of M1-Mn.

Technical Field

The invention belongs to the technical field of filters, and particularly relates to a filter with reconfigurable orders and types.

Background

In the current wireless radio frequency system, a receiver mostly adopts a low intermediate frequency structure, and radio frequency signals in the structure are subjected to quadrature down-conversion to low intermediate frequency, so that direct current offset is effectively avoided, and 1/f noise is reduced. By adopting orthogonal frequency conversion, under ideal conditions, the interference of image signals can be effectively inhibited, so that a receiver and a transmitter in a low-intermediate frequency structure become the current mainstream structure. In a low-intermediate frequency receiver-transmitter, a receiving front end needs to perform complex filtering on a signal to reduce image interference, an analog-to-digital conversion needs to be performed on the signal at a transmitting end, and then a low-pass filter needs to be used for suppressing a high-frequency noise signal. The complex filter is obtained by shifting a frequency spectrum through a low-pass filter, and in the process of shifting the frequency spectrum of the conventional complex filter, a cross coupling resistor is generally selected to be a fixed value, so that the uncertainty of the intermediate frequency is increased, the resistance change under an extreme process angle is large, the offset of the intermediate frequency is caused, and the yield of chips after chip flowing is not high. Moreover, the reconfigurable filter of the low-pass and the band-pass can save area and power consumption.

Disclosure of Invention

The technical problem is as follows: in order to overcome the defects in the prior art, the invention provides a filter with reconfigurable orders and types, the invention realizes the spectrum shift of a radio frequency I channel and a radio frequency Q channel by using a cross coupling circuit, and utilizes a peripheral control logic to generate a control signal to control the resistance values of the resistor arrays of a first module, a second module, a third module and a fourth module of the cross coupling circuit, thereby realizing the function of adjusting the intermediate frequency of a complex filter, and further avoiding the conditions of intermediate frequency offset and low chip yield after chip flow caused by the change of the resistance values under an extreme process angle due to the use of a cross coupling resistor with fixed resistance value. And the structure can realize the switching of the order and the filter function by controlling the switch so as to meet different performance requirements.

The technical scheme is as follows: in order to achieve the purpose, the invention adopts the technical scheme that:

a filter with reconfigurable order and type comprises an I-channel signal channel, a Q-channel signal channel, a cross-coupling circuit,

the I path signal channel and the Q path signal channel are used for realizing second-order low-pass filtering;

and the cross coupling circuit is used for connecting the control signal generated by the peripheral control logic for realizing frequency spectrum shifting to control the cross coupling circuit and realize the adjustment of the intermediate frequency.

As a further preferable solution of the filter with reconfigurable order and type of the present invention, the I-channel signal channel includes a positive input terminal of the first rf signal I-channel, a negative input terminal of the first rf signal I-channel, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a first capacitor, a second capacitor, a third capacitor, a first operational amplifier, a positive output terminal of the first rf signal I-channel, and a negative input terminal of the first rf signal I-channel;

the other end of the fourth resistor is connected with one end of a third switch, the other end of the third switch is connected with the positive output end of the first operational amplifier, and the other end of the second resistor is connected with the positive input end of the first operational amplifier; the negative end of the second capacitor is connected with the negative output end of the first operational amplifier and one end of the third resistor respectively, and the positive end of the second capacitor is connected with the positive input end of the first operational amplifier and one end of the third resistor respectively; the negative output end of the first operational amplifier is the negative output end of the first radio-frequency signal I path, and the positive output end of the first operational amplifier is the positive output end of the first radio-frequency signal I path; the negative input end of the first radio-frequency signal I path is connected with one end of a sixth resistor, and the other end of the sixth resistor is respectively connected with one end of a seventh resistor, one end of a first switch and one end of a fifth resistor; the other end of the first switch is connected with the negative end of the first capacitor, and the other end of the fifth resistor is connected with one end of the fourth switch; the other end of the fourth switch is connected with the output negative end of the first operational amplifier, the other end of the seventh resistor is respectively connected with the anode of the third capacitor, and one end of the eighth resistor (R8) is connected with the negative input end of the first operational amplifier; the other end of the eighth resistor (R8) is respectively connected with the anode output end of the second operational amplifier and the negative end of the third capacitor.

As a further preferable solution of the filter with reconfigurable order and type according to the present invention, the Q-path signal channel includes a positive input end of a second radio frequency signal Q-path, a negative output end of a first radio frequency signal Q-path, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a second operational amplifier, a positive output end of the first radio frequency signal Q-path, and a negative input end of the second radio frequency signal Q-path;

the positive input end of the second radio-frequency signal Q circuit is connected with one end of a ninth resistor, the other end of the ninth resistor is respectively connected with one end of a tenth resistor, the positive end of a fourth capacitor and one end of a twelfth resistor, the other end of the twelfth resistor is connected with one end of a fifth switch, and the other end of the fifth switch is connected with the output positive end of the second operational amplifier; the other end of the tenth resistor (R10) is respectively connected with the input positive end of the second operational amplifier and the positive end of the fifth capacitor; the negative end of a fifth capacitor is connected with the output negative end of a second operational amplifier and one end of an eleventh resistor respectively, the positive end of the fifth capacitor is connected with the input positive end of the second operational amplifier and one end of an eleventh resistor respectively, the output negative end of the second operational amplifier is the negative output end of a first radio-frequency signal Q circuit, the output positive end of the second operational amplifier is the output positive electrode of the first radio-frequency signal Q circuit, the negative input end of the second radio-frequency signal Q circuit is connected with one end of a fourteenth resistor, the other end of the fourteenth resistor is connected with one end of a fifteenth resistor, one end of a thirteenth resistor and one end of a second switch respectively, the other end of the second switch is connected with the negative end of a fourth capacitor, the other end of the thirteenth resistor is connected with one end of a sixth switch, and the other end of the sixth switch is connected with the negative output end of the second operational amplifier; the other end of the fifteenth resistor is connected with the anode of the sixth capacitor, one end of the sixteenth resistor is connected with the cathode input end of the second operational amplifier, and the other end of the sixteenth resistor is connected with the anode output end of the second operational amplifier and the negative end of the sixth capacitor.

As a further preferable solution of the filter with reconfigurable order and type of the present invention, the cross-coupling circuit includes a first cross-coupling module, a second cross-coupling module, and a control logic;

one end of the first cross coupling module is connected with one end of a seventh switch, the other end of the seventh switch is connected with the positive input end of the first operational amplifier, the other end of the first cross coupling module is connected with the negative output end of the second operational amplifier, one end of the second cross coupling module is connected with one end of an eighth switch, the other end of the eighth switch is connected with the negative input end of the first operational amplifier, and the other end of the second cross coupling module is connected with the positive output end of the second operational amplifier; one end of the third cross coupling module is connected with one end of a ninth switch, the other end of the ninth switch is connected with the positive electrode output end of the first operational amplifier, the other end of the third cross coupling module is connected with the positive electrode input end of the second operational amplifier, one end of the fourth cross coupling module is connected with one end of a tenth switch, the negative electrode output end of the first operational amplifier is arranged at the other end of the tenth switch, the other end of the fourth cross coupling module is connected with the input positive end of the second operational amplifier, the four modules of the cross coupling circuit have the same structure, and control signals S1-Sn generated by control logic are respectively connected with the grid electrodes of M1-Mn; the source of M1-Mn is connected with one end of R1-Rn; the Rconstant resistors are respectively connected with the drain of M1-Mn.

Has the advantages that: the filter can be realized, compared with the prior art, the filter has the following effects:

the invention replaces the traditional cross coupling resistor with fixed resistance value by the cross coupling module, thereby avoiding the conditions of medium frequency offset and low chip yield after chip flowing caused by the change of the resistance value under an extreme process angle. The cross coupling module is controlled by the control signal to adjust the intermediate frequency, and the structure can realize the switching of the order and the filter function by controlling the switch, can be used as a first-order or second-order basic unit, and can be cascaded with a higher-order intermediate frequency controllable band-pass or low-pass filter, and compared with the similar filter, the structure has lower power consumption.

Drawings

FIG. 1 is a circuit diagram of a reconfigurable filter of the present invention;

FIG. 2 is a cross-coupled circuit module according to the present invention;

FIG. 3 is a graph showing the amplitude-frequency characteristics of a second-order complex filter according to the present invention;

fig. 4 shows a fourth-order butterworth complex bandpass filter implemented by cascading the present invention.

Detailed Description

The present invention will be further described with reference to the accompanying drawings.

As shown in fig. 1, a filter with reconfigurable order and type includes: the signal path I, the signal path Q and the cross coupling circuit; the I path signal channel and the Q path signal channel are used for realizing second-order low-pass filtering; the cross coupling circuit is composed of four cross coupling modules with the same structure, is used for connecting an I signal channel and a Q signal channel to realize frequency spectrum shifting, and controls the resistance value of a resistor array in each cross coupling module according to a control signal generated by external control logic to realize the adjustment of intermediate frequency. Furthermore, the order and type of the filter can be changed by switching the switch state. When all the switches are closed, the circuit realizes a second-order band-pass filtering function; when the switches S7 and S … 10 are both open and the other switches are both closed, the circuit realizes a second-order low-pass filtering function; when the switches S1, S2, S3, S4, S5 and S6 are all opened and other switches are all closed, the circuit realizes a first-order low-pass filtering function; when both switches S7, … S10 are closed and the other switches are open, the circuit implements a first order bandpass filtering function.

As shown in fig. 2, the I-path signal path includes a positive input terminal Vin _ I + of the first rf signal I-path, a negative input terminal Vin _ I-of the first rf signal I-path, a first resistor Rl, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a first capacitor Cl, a second capacitor C2, a third capacitor C3, a first operational amplifier, a positive output terminal Vout _ I + of the first rf signal I-path, and a negative input terminal Vin _ I-of the first rf signal I-path;

the other end of the first radio-frequency signal I path is connected with one end of a first resistor Rl, the other end of the first resistor Rl is respectively connected with one end of a second resistor R2, the positive end of a first capacitor Cl and one end of a fourth resistor R4, the other end of the fourth resistor R4 is connected with one end of a third switch S3, the other end of the third switch S3 is connected with the positive output end of the first operational amplifier, and the other end of the second resistor R2 is respectively connected with the positive input end of the first operational amplifier; the negative end of the second capacitor C2 is respectively connected with the negative output end of the first operational amplifier and one end of the third resistor R3, and the positive end of the second capacitor C2 is respectively connected with the positive input end of the first operational amplifier and one end of the third resistor R3; the negative output end of the first operational amplifier is a negative output end Vout _ I of a first radio-frequency signal I path, and the positive output end of the first operational amplifier is a positive output end Vout _ I + of the first radio-frequency signal I path; the negative input end Vin _ I-of the first radio frequency signal I way is connected with one end of a sixth resistor R6, and the other end of the sixth resistor R6 is respectively connected with one end of a seventh resistor R7, one end of a first switch Sl and one end of a fifth resistor R5; the other end of the first switch S1 is connected to the negative terminal of the first capacitor C1, and the other end of the fifth resistor R5 is connected to one end of the fourth switch S4; the other end of the fourth switch S4 is connected with the output negative end of the first operational amplifier, the other end of the seventh resistor R7 is respectively connected with the anode of the third capacitor C3, and one end of the eighth resistor R8 is connected with the negative input end of the first operational amplifier; the other end of the eighth resistor R8 is connected to the positive output terminal of the second operational amplifier and the negative terminal of the third capacitor C3, respectively.

The Q-path signal channel comprises a positive input end Vin _ Q + of the second radio-frequency signal Q path, a negative output end Vout _ Q-of the first radio-frequency signal Q path, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a second operational amplifier, a positive output end Vout _ Q + of the first radio-frequency signal Q path, and a negative input end Vin _ Q-of the second radio-frequency signal Q path;

the positive input end Vin _ Q + of the second radio-frequency signal Q-path is connected with one end of a ninth resistor R9, the other end of the ninth resistor R9 is respectively connected with one end of a tenth resistor R10, the positive end of a fourth capacitor C4 and one end of a twelfth resistor R12, the other end of the twelfth resistor R12 is connected with one end of a fifth switch S5, and the other end of the fifth switch S5 is connected with the positive output end of the second operational amplifier; the other end of the tenth resistor R10 is respectively connected with the input positive end of the second operational amplifier and the positive end of the fifth capacitor; the negative end of a fifth capacitor C5 is connected with the output negative end of the second operational amplifier and one end of an eleventh resistor R11, respectively, the positive end of a fifth capacitor C5 is connected with the input positive end of the second operational amplifier and one end of an eleventh resistor R11, respectively, the output negative end of the second operational amplifier is the negative output end Vout _ Q of the first radio frequency signal Q-way, the output positive end of the second operational amplifier is the output positive pole Vout _ Q + of the first radio frequency signal Q-way, the negative input end Vin _ Q-of the second radio frequency signal Q-way is connected with one end of a fourteenth resistor R14, the other end of the fourteenth resistor R14 is connected with one end of a fifteenth resistor R15, one end of a thirteenth resistor R13 is connected with one end of a second switch S2, the other end of the second switch S2 is connected with the negative end of a fourth capacitor C4, the other end of the thirteenth resistor R13 is connected with one end of a sixth switch S6, and the other end of the sixth switch S6 is connected with the negative output end of the second operational amplifier; the other end of the fifteenth resistor R15 is connected to the anode of the sixth capacitor C6, one end of the sixteenth resistor R16 is connected to the cathode input end of the second operational amplifier, and the other end of the sixteenth resistor R16 is connected to the anode output end of the second operational amplifier and the cathode of the sixth capacitor C6.

The cross-coupling circuit includes a first cross-coupling module T1, a second cross-coupling module T2, a second cross-coupling module T3, a second cross-coupling module T4, and control logic;

one end of the first cross-coupling module T1 is connected to one end of the seventh switch S7, the other end of the seventh switch S7 is connected to the positive input end of the first operational amplifier, the other end of the first cross-coupling module T1 is connected to the negative output end of the second operational amplifier, one end of the second cross-coupling module T2 is connected to one end of the eighth switch S8, the other end of the eighth switch S8) is connected to the negative input end of the first operational amplifier, and the other end of the second cross-coupling module (T2) is connected to the positive output end of the second operational amplifier; one end of a third cross coupling module T3 is connected with one end of a ninth switch S9, the other end of the ninth switch S9 is connected with the positive electrode output end of the first operational amplifier, the other end of the third cross coupling module T3 is connected with the positive electrode input end of the second operational amplifier, one end of a fourth cross coupling module T4 is connected with one end of a tenth switch S10, the negative electrode output end of the first operational amplifier is arranged at the other end of the tenth switch S10, the other end of the fourth cross coupling module T4 is connected with the input positive end of the second operational amplifier, the four modules of the cross coupling circuit have the same structure, and control signals S1-Sn generated by control logic are respectively connected with the grids of M1-Mn; the source of M1-Mn is connected with one end of R1-Rn; the Rconstant resistors are respectively connected with the drain of M1-Mn.

As shown in fig. 3, an amplitude-frequency characteristic curve of the second-order filter of this embodiment shows that the control signal controls the access of the resistor array of the cross-coupling module, so as to change the effect of the intermediate frequency.

As shown in fig. 4, the fourth order butterworth complex bandpass filter implemented by cascade in this example includes two second order complex bandpass filters. Each second-order complex band-pass filter comprises an I-path signal channel, a Q-path signal channel and a cross coupling circuit as shown in the figure I.

The fourth order butterworth complex band-pass filter, wherein the positive input Vin _ I + of the first rf signal I path is connected to the positive I input terminal VIP1_ I of the first second order complex filter F1, and the negative input Vin _ I + of the first rf signal I path is connected to the negative I input terminal Vin1_ I of the first second order complex filter F1; the positive input Vin _ Q + of the second radio frequency signal I path is connected with the I path input positive terminal VIP1_ Q of the first two-order complex filter F1, and the negative input Vin _ Q + of the first radio frequency signal I path is connected with the I path input negative terminal VIN1_ Q of the first two-order complex filter F1; the output signal Vout1_ I + of the I-output positive electrode VOP1_ I of the first second-order complex filter F1 is connected to the I-input negative terminal VIN2_ I of the second-order complex filter F2; the output signal Vout1_ I-of the negative I-output VON1_ I of the first second-order complex filter F1 is connected to the positive I-input terminal VIP2_ I of the second-order complex filter F2; the Q-output positive pole VOP1_ Q output signal Vout1_ Q + of the first second-order complex filter F1 is connected to the Q-input negative pole VIN2_ Q of the second-order complex filter F2; the output signal Vout1_ Q-of the Q-way output cathode VON1_ Q of the first second-order complex filter F1 is connected with the Q-way input positive terminal VIP2_ Q of the second-order complex filter F2; the output positive pole signal of the I path of the second-order complex filter F2 is Vout2_ I +; the output negative electrode signal of the I path of the second-order complex filter F2 is Vout2_ I-; the Q-path output positive electrode output signal of the second-order complex filter F2 is Vout2_ Q +; the Q output negative output signal of the second order complex filter F2 is Vout2_ Q-.

Therefore, the innovation of the invention is that the frequency spectrum shifting of the radio frequency I channel and the radio frequency Q channel is realized by using the cross coupling circuit, and the control signals generated by the peripheral control logic are used for controlling the resistance values of the resistor arrays of the first module, the second module, the third module and the fourth module of the cross coupling circuit, so as to realize the function of adjusting the intermediate frequency of the complex filter, thereby avoiding the conditions of intermediate frequency offset and low chip yield after chip flowing caused by the change of the resistance value under an extreme process angle due to the use of the cross coupling resistor with a fixed resistance-value. Moreover, the structure can realize the switching of the order and the filter function by controlling the switch so as to meet different performance requirements.

The above description is only a preferred embodiment of the present invention, and it should be noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the invention and these are intended to be within the scope of the invention.