Integrating Circuit and Signal Processing Module

Abstract

The present disclosure provides an integrating circuit and a signal processing module. The integrating circuit comprises an operational amplifier; an integrating capacitor, coupled to an output terminal and a first input terminal of the operational amplifier; and an adjustable resistance module, coupled between the first input terminal of the operational amplifier and an integrating input terminal of the integrating circuit. The adjustable resistance module receives a plurality of first control signals, to adjust a resistance value of the adjustable resistance module. The present disclosure may realize the noise brought by sidelobe to enhance the SNR, and reduce the power consumption and complexity of the overall circuit.

Claims

1. An integrating circuit, comprising: a first operational amplifier; an integrating capacitor or an adjustable integrating capacitor module, coupled between an output terminal and a first input terminal of the operational amplifier; and an adjustable resistance module and/or a switched-capacitor module, coupled between the first input terminal of the operational amplifier and an integrating input terminal of the integrating circuit, wherein the switched-capacitor module comprises an adjustable capacitance module, and the adjustable resistance module is configured to receive a plurality of first control signals, to adjust a resistance value of the adjustable resistance module, and/or the adjustable capacitance module is configured to receive a plurality of second control signals, to adjust a capacitance value between a first terminal and a second terminal of the adjustable capacitance module.

2. The integrating circuit of claim 1, wherein the adjustable resistance module comprises a plurality of resistor-selecting units controlled by the plurality of first control signals respectively, and each resistor-selecting unit comprises: a resistor; and a resistance-control switch, coupled to the resistor.

3. The integrating circuit of claim 2, wherein the plurality of resistor-selecting units are connected to each other in parallel, and the resistor and the resistance-control switch of each resistor-selecting unit are connected to each other in series.

4. The integrating circuit of claim 2, wherein the plurality of resistor-selecting units are connected to each other in series, and the resistor and the resistance-control switch of each resistor-selecting unit are connected to each other in parallel.

5. The integrating circuit of claim 1, wherein the switched-capacitor module further comprises: a first switch, coupled between the first terminal of the adjustable capacitance module and the integrating input terminal; a second switch, coupled between the first terminal of the adjustable capacitance module and a ground; a third switch, coupled between the second terminal of the adjustable capacitance module and the first input terminal of the operational amplifier; and a fourth switch, coupled between the second terminal of the adjustable capacitance module and the ground.

6. The integrating circuit of claim 5, wherein the adjustable capacitance module comprises a plurality of capacitor-selecting units controlled by the plurality of second control signals respectively, to adjust the capacitance value of the adjustable capacitance module, and each capacitor-selecting unit comprises: a capacitor; and a capacitance-control switch, coupled to the capacitor.

7. The integrating circuit of claim 6, wherein the plurality of capacitor-selecting units are connected to each other in parallel, the capacitor and the capacitance-control switch of each capacitor-selecting unit are connected to each other in series; or wherein the plurality of capacitor-selecting units are connected to each other in series, the capacitor and the capacitance-control switch of each capacitor-selecting unit are connected to each other in parallel.

8. The integrating circuit of claim 5, wherein the switched-capacitor module further comprises: at least a resistor unit, coupled between the first switch and the third switch.

9. A signal processing module, comprising: a switching mixer; an analog-to-digital converter; an integrating circuit, coupled between the switching mixer and the analog-to-digital converter, the integrating circuit comprises: an operational amplifier; an integrating capacitor unit, coupled to an output terminal and a first input terminal of the operational amplifier; and an adjustable module, coupled between the first input terminal of the operational amplifier and an integrating input terminal of the integrating circuit, wherein the adjustable module is controlled by a plurality of signals, to adjust a resistance value or a capacitance value of the adjustable module.

10. The signal processing module of claim 9, wherein the adjustable module comprises an adjustable resistance module, and the adjustable resistance module is configured to receive a plurality of first control signals, to adjust the resistance value of the adjustable resistance module.

11. The signal processing module of claim 10, wherein the adjustable resistance module comprises a plurality of resistor-selecting units controlled by the plurality of first control signals respectively, and each resistor-selecting unit comprises: a resistor; and a resistance-control switch, coupled to the resistor.

12. The signal processing module of claim 11, wherein the plurality of resistor-selecting units are connected to each other in parallel, and the resistor and the resistance-control switch of each resistor-selecting unit are connected to each other in series signal; or wherein the plurality of resistor-selecting units are connected to each other in series, and the resistor and the resistance-control switch of each resistor-selecting unit are connected to each other in parallel.

13. The signal processing module of claim 9, wherein the adjustable module comprises a switched-capacitor module, coupled between the first input terminal of the operational amplifier and the integrating input terminal of the integrating circuit, and the switched-capacitor module comprises: an adjustable capacitance module, configured to receive a plurality of second control signals, to adjust a capacitance value between a first terminal and a second terminal of the adjustable capacitance module; a first switch, coupled between the first terminal and the integrating input terminal; a second switch, coupled between the first terminal and a ground; a third switch, coupled between the second terminal and the first input terminal of the operational amplifier; and a fourth switch, coupled between the second terminal and the ground.

14. The signal processing module of claim 13, wherein the adjustable capacitance module comprises a plurality of capacitor-selecting units controlled by the plurality of second control signals respectively, and each capacitor-selecting unit comprises: a capacitor; and a capacitance-control switch, coupled to the capacitor.

15. The signal processing module of claim 14, wherein the plurality of capacitor-selecting units are connected to each other in parallel, the capacitor and the capacitance-control switch of each capacitor-selecting unit are connected to each other in series signal; or wherein the plurality of capacitor-selecting units are connected to each other in series, the capacitor and the capacitance-control switch of each capacitor-selecting unit are connected to each other in parallel.

16. The signal processing module of claim 13, wherein the switched-capacitor module further comprises: at least a resistor unit, coupled between the first switch and the third switch.

17. An integrating circuit, comprising: a first operational amplifier; an adjustable integrating capacitor module, coupled between a first input terminal and an output terminal of the first operational amplifier, wherein the adjustable integrating capacitor module comprises a plurality of integrating-capacitor-selecting units, and each integrating-capacitor-selecting unit comprises an integrating capacitor and at least a switch; and a voltage following module, coupled to the plurality of integrating-capacitor-selecting units of the adjustable integrating capacitor module; wherein the adjustable integrating capacitor module is configured to receive a plurality of control signals, to adjust a capacitance value between the first input terminal and the output terminal.

18. The integrating circuit of claim 17, wherein the voltage following module comprises a plurality of nodes, and the plurality of nodes are electrically connected to the integrating capacitors of the plurality of integrating-capacitor-selecting units, respectively.

19. The integrating circuit of claim 18, wherein the voltage following module comprises a voltage following circuit, and each node of the plurality of nodes is coupled to an input terminal of the voltage following circuit through a first switch and coupled to an output terminal of the voltage following circuit through a second switch.

20. The integrating circuit of claim 19, wherein the voltage following circuit comprises a second operational amplifier, wherein a first input terminal of the second operational amplifier is electrically connected to an output terminal of the second operational amplifier, a second input terminal of the second operational amplifier is the input terminal of the voltage following circuit, and an output terminal of the second operational amplifier is the output terminal of the voltage following circuit.

21. The integrating circuit of claim 17, wherein the plurality of integrating-capacitor-selecting units are connected to each other in parallel or in series.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 is a schematic diagram of a plurality of waveforms.

[0013] FIG. 2 is a schematic diagram of an integrating circuit according to an embodiment of the present disclosure.

[0014] FIG. 3 is a waveform of an output signal of the integrating circuit of FIG. 2.

[0015] FIG. 4 is a schematic diagram of an integrating circuit according to an embodiment of the present disclosure.

[0016] FIG. 5 is a schematic diagram of an integrating circuit according to an embodiment of the present disclosure.

[0017] FIG. 6 is a schematic diagram of an integrating circuit according to an embodiment of the present disclosure.

[0018] FIG. 7 is a schematic diagram of an integrating circuit according to an embodiment of the present disclosure.

[0019] FIG. 8 is a schematic diagram of a switched-capacitor module according to an embodiment of the present disclosure.

[0020] FIG. 9 is a schematic diagram of an integrating circuit according to an embodiment of the present disclosure.

[0021] FIG. 10 is a schematic diagram of a signal processing module according to an embodiment of the present disclosure.

[0022] FIG. 11 is a schematic diagram of an integrating circuit according to an embodiment of the present disclosure.

[0023] FIG. 12 is a schematic diagram of an integrating circuit according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

[0024] The present disclosure utilizes an analog integrating circuit to realize an effect of window function, which is able to adjust different integration gains corresponding to different time intervals at the different time intervals. Please refer to FIG. 2. FIG. 2 is a schematic diagram of an integrating circuit 20 according to an embodiment of the present disclosure. The integrating circuit 20 is a resistor-capacitor (RC) integrator, which includes an operational amplifier Amp, an integrating capacitor C.sub.I and an adjustable resistance module VR. The operational amplifier Amp includes a negative input terminal (denoted as ), a positive input terminal (denoted as +) and an output terminal. The integrating capacitor C.sub.I is coupled between the negative input terminal and the output terminal of the operational amplifier Amp. The adjustable resistance module VR is coupled between the negative input terminal of the operational amplifier Amp and an integrating input terminal N.sub.IN of the integrating circuit 20. The adjustable resistance module VR includes resistor-selecting units RU.sub.1-RU.sub.M. The adjustable resistance module VR is formed by the resistor-selecting units RU.sub.1-RU.sub.M connected to each other in parallel, wherein any resistor-selecting unit RU.sub.m of the resistor-selecting units RU.sub.1-RU.sub.M includes a resistor R.sub.m and a resistance-control switch S.sub.Rm. The resistance-control switch S.sub.Rm is controlled by a control signal ctrl_R_m. The resistor-selecting unit RU.sub.m is formed by the resistor R.sub.m connected to the resistance-control switch S.sub.Rm in series. In other words, the control signals ctrl_R_1-ctrl_R_M may control the adjustable resistance module VR to adjust a resistance value between a first terminal NR.sub.1 and a second terminal NR.sub.2 of the adjustable resistance module VR, so as to change the integration gain of the integrating circuit 20 at different time intervals.

[0025] Operation of the integrating circuit 20 changing the integration gain at different time intervals may be referred to FIG. 3. FIG. 3 illustrates a waveform of an output signal V.sub.OUT of the integrating circuit 20 when an input signal V.sub.IN of the integrating circuit 20 is a DC (Direct Current) signal. As can be seen from FIG. 3, the resistance value between the first terminal NR.sub.1 and the second terminal NR.sub.2 of the adjustable resistance module VR may be adjusted with respect to time intervals T.sub.1-T.sub.7 by the control signals ctrl_R_1-ctrl_R_M, such that the integrating circuit 20 has different integration gains at the time intervals T.sub.1-T.sub.7. To realize the window function, preferably, the time intervals T.sub.1, T.sub.7 may have the smallest integration gain, the time intervals T.sub.2, T.sub.5 may have the second smallest integration gain, and the time interval T.sub.4 at the center may have the largest integration gain.

[0026] In addition, please refer to FIG. 4. FIG. 4 is a schematic diagram of an integrating circuit 40 according to an embodiment of the present disclosure. The integrating circuit 40 is similar to the integrating circuit 20, and thus, same components are denoted by the same symbols. Different from the integrating circuit 20, the integrating circuit 40 is a switched-capacitor integrator. The integrating circuit 40 includes a switched-capacitor module SCM. The switched-capacitor module SCM is coupled between the negative input terminal of the operational amplifier Amp and the integrating input terminal N.sub.IN of the integrating circuit 40. The switched-capacitor module SCM includes an adjustable capacitance module VC and switches SW1-SW4. The switches SW1, SW2 are coupled to a first terminal NC.sub.1 of the adjustable resistance module VC. The switches SW3, SW4 are coupled to a second terminal NC.sub.2 of the adjustable resistance module VC. The switches SW2, SW4 are coupled to a ground. The adjustable capacitance module VC includes capacitor-selecting units CU.sub.1-CU.sub.N. The adjustable capacitance module VC is formed by the capacitor-selecting units CU.sub.1-CU.sub.N connected to each other in parallel, where any capacitor-selecting unit CU.sub.n within the capacitor-selecting units CU.sub.1-CU.sub.N includes a capacitor C.sub.n and a capacitance-control switch S.sub.Cn. The capacitance-control switch S.sub.Cn is controlled by a control signal ctrl_C_n. The capacitor-selecting unit CU.sub.n is formed by the capacitor C.sub.n connected to the capacitance-control switch S.sub.Cn in series. In other words, the control signals ctrl_C_1-ctrl_C_N may be configured to control the adjustable capacitance module VC, to adjust a capacitance value between the first terminal NC.sub.1 and the second terminal of the adjustable capacitance module VC at the different time intervals, so as to change integration gain of the integrating circuit 40 at different time intervals.

[0027] In addition, the switches SW1, SW2, SW3, SW4 maybe controlled by frequency control signals ph1, ph2, where the frequency control signals ph1, ph2 are mutually orthogonal frequency control signals (i.e., time intervals of the frequency control signals ph1, ph2 being high voltage are not overlapped). Specifically, in an embodiment, the frequency control signal ph1 may be configured to control conduction status of the switches SW1, SW3, and the frequency control signal ph2 may be configured to control conduction status of the switches SW2, SW4. In another embodiment, the frequency control signal ph1 may be configured to control conduction status of the switches SW1, SW4, and the frequency control signal ph2 may be configured to control conduction status of the switches SW2, SW3. As long as the mutually orthogonal frequency control signals ph1, ph2 are utilized to control the conduction status of the switches SW1, SW2, SW3, SW4, requirements of present disclosure is satisfied, which is within the scope of present disclosure.

[0028] As can be seen, the integrating circuit 20 and the integrating circuit 40 utilize the adjustable resistance module VR and the adjustable capacitance module VC to adjust the resistance value of the adjustable resistance module VR and the capacitance value of the adjustable capacitance module VC at the different time intervals. In other words, the integrating circuit 20 and the integrating circuit 40 may change the integration gains of the integrating circuit 20 and the integrating circuit 40 at the different time intervals, so as to realize an effect of window function. Therefore, the integrating circuit 20 and the integrating circuit 40 may reduce noise brought by sidelobe, so as to enhance an overall SNR (Signal to Noise Ratio).

[0029] It should be noted that, the embodiments stated in the above are utilized for illustrating the concept of the present disclosure. Those skilled in the art may make modifications and alternations accordingly, and not limited herein. For example, in the adjustable resistance module VR, the resistor-selecting units RU.sub.1-RU.sub.M are connected to each other in parallel, and the resistor R.sub.m is connected to the resistance-control switch S.sub.Rm in series. In the adjustable capacitance module VC, the capacitor-selecting units CU.sub.1-CU.sub.N are connected to each other in parallel, and the capacitor C.sub.n is connected to the capacitance-control switch S.sub.Cn, which is not limited thereto. Please refer to FIG. 5. FIG. 5 is a schematic diagram of an integrating circuit 50 according to an embodiment of the present disclosure. The integrating circuit 50 is similar to the integrating circuit 20, and thus, same components are denoted by the same symbols. Different from the integrating circuit 20, the integrating circuit 50 includes an adjustable resistance module VR. The adjustable resistance module VR includes the resistor-selecting units RU.sub.1-RU.sub.M. The adjustable resistance module VR is formed by the resistor-selecting units RU.sub.1-RU.sub.M connected to each other in series, wherein any resistor-selecting unit RU.sub.m within the resistor-selecting units RU.sub.1-RU.sub.M includes a resistor R.sub.m and a resistance-control switch S.sub.Rm. The resistance-control switch S.sub.Rm is controlled by a control signal ctrl_R_m. The resistor-selecting unit RU.sub.m is formed by the resistor R.sub.m connected to the resistance-control switch S.sub.Rm in parallel. Similarly, please refer to FIG. 6. FIG. 6 is a schematic diagram of an integrating circuit 60 according to an embodiment of the present disclosure. The integrating circuit 60 is similar to the integrating circuit 40, and thus, same components are denoted by the same symbols. Different from the integrating circuit 40, the integrating circuit 60 includes a switched-capacitor module SCM. The switched-capacitor module SCM includes an adjustable capacitance module VC. The adjustable capacitance module VC includes the capacitor-selecting units CU.sub.1-CU.sub.N. The adjustable capacitance module VC is formed by the capacitor-selecting units CU.sub.1-CU.sub.N connected to each other in series, wherein any capacitor-selecting unit CU.sub.n within the capacitor-selecting units CU.sub.1-CU.sub.N includes a capacitor C.sub.n and a capacitance-control switch S.sub.Cn. The capacitance-control switch S.sub.Cn is controlled by a control signal ctrl_C_n. The capacitor-selecting unit CU.sub.n is formed by the capacitor C.sub.n connected to the capacitance-control switch S.sub.Cn in parallel.

[0030] In addition, the integrating circuit may include the adjustable resistance module and the adjustable capacitance module at the same time. For example, please refer to FIG. 7. FIG. 7 is a schematic diagram of an integrating circuit 70 according to an embodiment of the present disclosure. The integrating circuit 70 is similar to the integrating circuit 20, and thus, same components are denoted by the same symbols. The integrating circuit 70 includes an adjustable resistance module 700 and a switched-capacitor module 702. The adjustable resistance module 700 and the switched-capacitor module 702 are both coupled between the negative input terminal of the operational amplifier Amp and the integrating input terminal N.sub.IN of the integrating circuit 70, wherein the adjustable resistance module 700 may be realized by the adjustable resistance module VR or the adjustable resistance module VR, the switched-capacitor module 702 may be realized by the switched-capacitor module SCM or the switched-capacitor module SCM, which is not limited thereto.

[0031] In addition, the switched-capacitor module is not limited to be realized by the switched-capacitor module SCM or the switched-capacitor module SCM stated in the above. The switched-capacitor module may further include a resistor coupled between the switches SW1 and SW3. For example, please refer to FIG. 8. FIG. 8 is a schematic diagram of a switched-capacitor module 80 according to an embodiment of the present disclosure. Different from the switched-capacitor module SCM, SCM, the switched-capacitor module 80 further includes a resistor unit R coupled between the switches SW1 and SW3, where the resistor unit R may be one single resistor component or an adjustable resistance module , which is also within the scope of the present disclosure.

[0032] In addition, the adjustable resistance module or the switched-capacitor module stated in the above are applied in the integrating circuit with a single-ended input, which is not limited thereto. The adjustable resistance module or the switched-capacitor module may be applied in an integrating circuit with differential input. For example, please refer to FIG. 9. FIG. 9 is a schematic diagram of an integrating circuit 90 according to an embodiment of the present disclosure. The integrating circuit 90 receives differential input signals V.sub.I+, V.sub.I and generates differential output signals V.sub.O+, V.sub.O. The integrating circuit 90 includes a full differential operational amplifier FOP, the integrating capacitors C.sub.I and C.sub.I and adjustable modules 900 and 900. The adjustable module 900 and the adjustable module 900 may be realized by the adjustable resistance module VR, the adjustable resistance module VR, the switched-capacitor module SCM or the switched-capacitor module SCM. In addition, the adjustable module 900 and the adjustable module 900 may also be realized by the adjustable resistance module VR (or the adjustable resistance module VR) connected to the switched-capacitor module SCM (or the switched-capacitor module SCM), and not limited thereto. Preferably, the resistance values or the capacitance values of the adjustable module 900 and the adjustable module 900 may be controlled to be the same/consistent, so as to balance the differential signals, which is to improve the performance of the integrating circuit 90.

[0033] In addition, the integrating circuit 90 may be applied in a signal processing module. Please refer to FIG. 10. FIG. 10 is a schematic diagram of a signal processing module 12 according to an embodiment of the present disclosure. The signal processing module 12 includes a switching mixer 120, the integrating circuit 90 and an analog-to-digital converter ADC. The switching mixer 120 receives differential signals V.sub.IN+, V.sub.IN and generates the differential input signals V.sub.I+, V.sub.I to the integrating circuit 90. The analog-to-digital converter ADC receives the differential output signals V.sub.0+, V.sub.O generated by the integrating circuit 90, and converts the analog differential output signals V.sub.O+, V.sub.O into digital signals for the back-end circuit to perform further computing operations. The switching mixer 120 may include switches S1-S4. The switches S1, S2 are configured to receive the differential signal V.sub.IN. The switches S3, S4 are configured to receive the differential signal V.sub.IN+. The switches S1, S4 are coupled to a first input terminal of the integrating circuit 90 to deliver the differential input signal V.sub.I to the integrating circuit 90. The switches S2, S3 are coupled to a second input terminal of the integrating circuit 90 to deliver the differential input signal V.sub.I+ to the integrating circuit 90.

[0034] In addition, the integrating capacitor coupled between the input terminal and the output terminal of the operational amplifier Amp is realized by one single capacitor component, which is not limited thereto. The integrating capacitor coupled between the input terminal and the output terminal of the operational amplifier Amp may be realized by the adjustable capacitance module. Please refer to FIG. 11. FIG. 11 is a schematic diagram of an integrating circuit 14 according to an embodiment of the present disclosure. The integrating circuit 14 includes an adjustable integrating capacitor module 140, a voltage following module 142 and the operational amplifier Amp. The adjustable integrating capacitor module 140 is coupled between the positive and the negative input terminals and the output terminal of the operational amplifier Amp. The voltage following module 142 is coupled to the adjustable integrating capacitor module 140. Specifically, the adjustable integrating capacitor module 140 includes integrating-capacitor-selecting units CIU.sub.1-CIU.sub.N. The adjustable integrating capacitor module 140 is regarded as being formed by the integrating-capacitor-selecting units CIU.sub.1-CIU.sub.N connected to each other in parallel. Any integrating-capacitor-selecting unit CIU.sub.n within the integrating-capacitor-selecting units CIU.sub.1-CIU.sub.N includes an integrating capacitor C.sub.In and the switches M.sub.n, J.sub.n. The integrating capacitor C.sub.In and the switches M.sub.n, J.sub.n are connected in series. The integrating capacitor C.sub.In is coupled to the positive and the negative input terminals of the operational amplifier Amp through the switch M.sub.n. The integrating capacitor C.sub.In is coupled to the output terminal of the operational amplifier Amp through the switch J.sub.n.

[0035] In addition, the voltage following module 142 includes switches H.sub.1-H.sub.N, K.sub.1-K.sub.N and a voltage following circuit 144. The voltage following circuit 144 includes an operational amplifier OP. A negative input terminal (denoted as ) of the operational amplifier OP is coupled to an output terminal of the operational amplifier OP. The output terminal of the operational amplifier OP is coupled to the switches K.sub.1-K.sub.N. A positive input terminal (denoted as +) is coupled to the switches H.sub.1-H.sub.N. In addition, the voltage following module 142 includes nodes ND.sub.1-ND.sub.N. The switches H.sub.1-H.sub.N are coupled to the switches K.sub.1-K.sub.N at the nodes ND.sub.1-ND.sub.N, respectively. In other words, a terminal of any switch H.sub.n within the switches H.sub.1-H.sub.N is coupled to the node ND.sub.n, and another terminal of the switch H.sub.n is coupled to the positive input terminal of the operational amplifier OP. A terminal of any switch K.sub.n within the switches K.sub.1-K.sub.N is coupled to the node ND.sub.n, and another terminal of the switch K.sub.n is coupled to the output terminal of the operational amplifier OP. Each node ND.sub.n within the nodes ND.sub.1-ND.sub.N is coupled between the integrating capacitor C.sub.In and the switch J.sub.n. The switches M.sub.1-M.sub.N, J.sub.1-J.sub.N, H.sub.1-H.sub.N, K.sub.1-K.sub.N may receive and be controlled by a plurality of control signals (not illustrated in FIG. 11) to perform integration operation, and the plurality of control signals may change the integration gain of the integrating circuit 14 at different time intervals, to adjust a capacitance value between the negative input terminal and the output terminal of the operational amplifier Amp, so as to realize the effect of the window function.

[0036] Detail operations of the integrating circuit 14 are described as follows. When the integrating circuit 14 performs integration on an integrating capacitor C.sub.Ip of the integrating capacitors C.sub.I1-C.sub.IN, the plurality of control signals controls the switches H.sub.1-H.sub.N, K.sub.1-K.sub.N to be cutoff. In addition, among the switches J.sub.1-J.sub.N, except a switch J.sub.p corresponding to the integrating capacitor C.sub.Ip is conducted, the plurality of control signals control the rest switches J.sub.1-J.sub.p1, J.sub.p+1-J.sub.N to be cutoff. In addition, the plurality of control signals control a switch M.sub.p corresponding to the integrating capacitor C.sub.Ip among the switches M.sub.1-M.sub.N to conduct a connection between the integrating capacitor C.sub.Ip and the negative input terminal of the operational amplifier Amp. Except the switch M.sub.p, the plurality of control signals control the rest switches M.sub.1-M.sub.p1, M.sub.p+1-M.sub.N to conduct connections between the integrating capacitor and the positive terminal of the operational amplifier Amp. Before the integrating circuit 14 switches to perform integration on another integrating capacitor C.sub.Ig of the integrating capacitors C.sub.I1-C.sub.IN from performing integration on the integrating capacitor C.sub.Ip, the plurality of control signals control the switch H.sub.p corresponding to the integrating capacitor C.sub.Ip and the switch K.sub.q corresponding to the integrating capacitor C.sub.Iq to be closed (i.e., the switches H.sub.p, K.sub.g are conducted) , and the rest switches H.sub.1-H.sub.p1, H.sub.p+1-H.sub.N, K.sub.1-K.sub.q1, K.sub.q+1-K.sub.N to be cutoff. Thus, the capacitance value between the negative input terminal and the output terminal of the operational amplifier Amp may be adjusted at the different time intervals, such that the integrating circuit 14 has different integration gains, so as to realize the effect of the window function.

[0037] In addition, in the integrating circuit 14, the adjustable integrating capacitor module 140 is regarded as being formed by the integrating-capacitor-selecting units CIU.sub.1-CIU.sub.N connected to each other in parallel, which is not limited herein. Please refer to FIG. 12. FIG. 12 is a schematic diagram of an integrating circuit 24 according to an embodiment of the present disclosure. The integrating circuit 24 is similar to the integrating circuit 14, and thus, same components are denoted by the same symbols. Different from the integrating circuit 14, the integrating circuit 24 includes an adjustable integrating capacitor module 240. The adjustable integrating capacitor module 240 includes the integrating-capacitor-selecting units CIU.sub.1-CIU.sub.N. The adjustable integrating capacitor module 240 is formed by the integrating-capacitor-selecting units CIU.sub.1-CIU.sub.N connected to each other in series. Any integrating-capacitor-selecting unit CIU.sub.n of the integrating-capacitor-selecting units CIU.sub.1-CIU.sub.N includes an integrating capacitor C.sub.In and switches M.sub.n, L.sub.n, J.sub.n. The integrating capacitor C.sub.In and the switches M.sub.n, L.sub.n are connected in series. That is, the integrating capacitor C.sub.In and the switches M.sub.n, L.sub.n are connected as a series, the switch J.sub.n is parallelly connected to the series formed by the integrating capacitor C.sub.In and the switches M.sub.n, L.sub.n.

[0038] Detail operations of the integrating circuit 24 are described as follows. When the integrating circuit 24 performs integration on an integrating capacitor C.sub.Ip within the integrating capacitors C.sub.I1-C.sub.IN, the switches H.sub.1-H.sub.N, K.sub.1-K.sub.N are cutoff. Within the switches J.sub.1-J.sub.N, except the switch J.sub.p corresponding to the integrating capacitor C.sub.Ip which is cutoff, the rest switches J.sub.1-J.sub.p1, J.sub.p+1-J.sub.N are conducted. In addition, the switch L.sub.p corresponding to the integrating capacitor C.sub.Ip within the switches L.sub.1-L.sub.N are conducted. A switch M.sub.p corresponding to the integrating capacitor C.sub.Ip within the switches M.sub.1-M.sub.N conducts a connection between the integrating capacitor C.sub.Ip and the negative input terminal of the operational amplifier Amp. Before the integrating circuit 24 switches to perform integration on another integrating capacitor C.sub.Iq within the integrating capacitors C.sub.I1-C.sub.IN from performing integration on the integrating capacitor C.sub.Ip, the switch H.sub.p corresponding to the integrating capacitor C.sub.Ip and the switch K.sub.q corresponding to the integrating capacitor C.sub.Iq are closed (i.e., the switches H.sub.p, K.sub.q are conducted) , and the rest switches H.sub.1-H.sub.p1, H.sub.p+1-H.sub.N, K.sub.1-K.sub.q1, K.sub.q+1-K.sub.N are cutoff. In addition, a switch M.sub.q corresponding to the integrating capacitor C.sub.Iq within the switches M.sub.1-M.sub.N conducts a connection between the integrating capacitor C.sub.Iq and the positive input terminal of the operational amplifier Amp. Thus, the capacitance value between the negative input terminal and the output terminal of the operational amplifier Amp may be adjusted at the different time intervals, such that the integrating circuit 14 has different integration gains to realize the effect of the window function.

[0039] Notably, the embodiments stated in the above are utilized for illustrating the best embodiments of the present disclosure, which is not limited thereto. For example, in FIG. 11, when the integrating capacitor C.sub.Iq does not perform integration, the corresponding switch M.sub.q is coupled to the positive input terminal of the operational amplifier Amp. In another embodiment (not illustrated), M.sub.q may be coupled to any reference voltage, and the reference voltage does not have to be the same as the positive input terminal of the operational amplifier Amp, which also brings different integration gain for the integrating circuit 14 to realize the effect of the window function. Similarly, when there is no integration performed on the integrating capacitor corresponding to the switches M.sub.1-M.sub.N, the switch may be coupled to any reference voltage, such that the integrating circuit 24 is utilized to realize the effect of the window function.

[0040] In summary, the present disclosure utilizes the adjustable resistance module or the adjustable capacitance module to change the integration gain of the integrating circuit at the different time intervals, so as to realize the window function, reduce noise brought by sidelobe and enhance the SNR. Compared to the related art, the integrating circuit of the present disclosure may reduce a requirement of sampling rate of the analog-to-digital converter, such that the power consumption and complexity of the overall circuit are reduced.

[0041] The foregoing is only preferred embodiments of the present disclosure, it is not intended to limit the present disclosure, any modifications within the spirit and principles of the present disclosure made, equivalent replacement and improvement, etc., should be included in this within the scope of the disclosure.

[0042] Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.