Signal adjustment circuit and receiving end circuit using the same

Abstract

The present invention discloses a signal adjustment circuit and a receiving end circuit using the same. The signal adjustment circuit is applicable to a peak detector and includes a first amplifier and a first feedback circuit. The first amplifier receives a first input signal and amplifies the first input signal to output a first output signal. The first feedback circuit is connected between a first input terminal and a first output terminal of the first amplifier and is used to determine a first gain of the first output signal. Wherein, the peak detector is connected to a first output node of the first feedback circuit to receive a first detection signal and detect a peak value of the first detection signal. Wherein, the peak detector has a predetermined power input range, and the first feedback circuit enables the first detection signal to be within the predetermined power input range.

Description

Technical Field

[0001] The present invention relates to a signal adjustment circuit and a receiving-end circuit using the same, and particularly to a signal adjustment circuit that can avoid adding extra components to adapt to a peak detector and a receiving-end circuit using the same. Background Art

[0002] In existing receiving-end circuits, a peak detector (PD) is often used to detect whether the peak value of an input signal exceeds a predetermined range, and the signal integrity cannot be maintained.

[0003] For example, if it is desired to apply a peak detector to detect the output signal of a transimpedance amplifier (TIA), in a generally well-designed situation, the linearity of the output signal of the transimpedance amplifier is good and close to the limit of the supply voltage. At this time, an attenuator needs to be used additionally. However, using more components will increase the amount of mismatch.

[0004] In another method, the peak detector can be set at the input end of the transimpedance amplifier for detection. However, since detection is to be performed when the signal has not been amplified, an additional preamplifier is required to enable the peak detector to work properly, but this will increase its variation. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a signal adjustment circuit that can avoid adding extra components to adapt to a peak detector and a receiving-end circuit using the same in view of the deficiencies of the prior art.

[0006] To solve the above technical problems, one of the technical solutions adopted by the present invention is to provide a signal adjustment circuit applicable to a peak detector. The signal adjustment circuit includes a first amplifier and a first feedback circuit. The first amplifier includes a first input terminal and a first output terminal. Among them, the first input terminal receives a first input signal, and the first amplifier is used to amplify the first input signal to output a first output signal from the first output terminal. The first feedback circuit includes a first capacitor, a first resistor, and a second resistor. The first capacitor is connected between the first input terminal and the first output terminal. The first resistor is connected between the first input terminal and a first output node. The second resistor is connected between the first output node and the first output terminal. Among them, the first feedback circuit is used to determine a first gain of the first output signal. Among them, the peak detector is connected to the first output node to receive a first detection signal and detect the peak value of the first detection signal. Among them, the peak detector has a predetermined power input range, and the first resistor and the second resistor have a first predetermined ratio, so that the first detection signal has a second gain relative to the first input signal and within the predetermined power input range.

[0007] To solve the above technical problems, another technical solution adopted by the present invention is to provide a receiving end circuit, including a transimpedance amplifier and a first peak detector. The transimpedance amplifier includes a first signal adjustment circuit, which includes a first amplifier, a first feedback circuit, and a first control circuit. The first amplifier includes a first input terminal and a first output terminal. Among them, the first input terminal receives a first input signal, and the first amplifier is used to amplify the first input signal to output a first output signal from the first output terminal. The first feedback circuit includes a first capacitor, a first variable resistor, and a second variable resistor. The first capacitor is connected between the first input terminal and the first output terminal. The first variable resistor is connected between the first input terminal and a first output node. The second variable resistor is connected between the first output node and the first output terminal. The first control circuit is configured to control the resistance values of the first variable resistor and the second variable resistor to determine a first gain of the first output signal relative to the first input signal, and a second gain of the first detection signal relative to the first input signal. The first peak detector is connected to the first output node to receive the first detection signal, has a first predetermined power input range, and is used to detect the peak value of the first detection signal. Among them, the first control circuit controls the resistance values of the first variable resistor and the second variable resistor to have a first predetermined ratio, so that the first detection signal is within the first predetermined power input range.

[0008] One of the beneficial effects of the present invention is that the signal adjustment circuit provided by the present invention and the receiving end circuit using the same can be combined with the appropriate design of the transimpedance amplifier or the baseband filter in the receiving end circuit. Without increasing the area, it is applicable to the receiving end peak detector without the need to additionally use an attenuator or a preamplifier, thereby reducing the mismatch caused by using the above-mentioned additional components.

[0009] In order to further understand the features and technical content of the present invention, please refer to the following detailed description and drawings of the present invention. However, the provided drawings are only for reference and illustration, and are not used to limit the present invention. Brief Description of the Drawings

[0010] Figure 1 It is a circuit layout diagram of the signal adjustment circuit according to the first embodiment of the present invention.

[0011] Figure 2A It is another circuit layout diagram of the signal adjustment circuit according to the first embodiment of the present invention.

[0012] Figure 2B It is another circuit layout diagram of the signal adjustment circuit according to the first embodiment of the present invention.

[0013] Figure 3 It is a circuit layout diagram of the signal adjustment circuit according to the second embodiment of the present invention applied to the receiving end circuit.

[0014] Figure 4 It is a block diagram of the receiving end circuit according to the third embodiment of the present invention.

[0015] Figure 5 It is a circuit architecture diagram of the transimpedance amplifier and the receiving end baseband filter of the receiving end circuit according to the third embodiment of the present invention. Detailed Description of the Invention

[0016] The following is to illustrate the implementation mode of the present invention related to "signal adjustment circuit and receiving end circuit using the same" through specific embodiments. Those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of the present invention. In addition, the drawings of the present invention are only for simple schematic illustration and are not drawn according to actual dimensions, which is stated in advance. The following embodiments will further detail the related technical content of the present invention, but the disclosed content is not used to limit the protection scope of the present invention. In addition, the term "or" used in this article may include any one or a combination of more of the related listed items depending on the actual situation. In addition, regarding the "connection" used in this specification, it may refer to two or more elements making direct physical or electrical contact with each other, or making indirect physical or electrical contact with each other, and may also refer to two or more elements operating or acting on each other.

[0017] [First Embodiment]

[0018] Figure 1 It is a circuit layout diagram of the signal adjustment circuit according to the first embodiment of the present invention.

[0019] Refer to Figure 1 As shown, the first embodiment of the present invention provides a signal adjustment circuit 10, which is applicable to a peak detector 12. The signal adjustment circuit 10 includes a first amplifier 100 and a first feedback circuit 102.

[0020] The first amplifier 100 has a first input terminal (left positive (+) terminal), a second input terminal (left negative (-) terminal), a first output terminal (right negative (-) terminal), and a second output terminal (right positive (+) terminal). The first input terminal receives a first input signal Sin1, and the first amplifier 100 is used to amplify the first input signal Sin1 to output a first output signal Sout1 from the first output terminal.

[0021] The first feedback circuit 102 includes a capacitor C1, a resistor R1, and a resistor R2. The capacitor C1 is connected between the first input terminal and the first output terminal. One end of the resistor R1 is connected to the first input terminal, and the other end is connected to the first output node N1. The resistor R2 is connected between the first output node N1 and the first output terminal. Among them, the first feedback circuit 102 is used to determine the first gain of the first output signal Sout1.

[0022] In this embodiment, the signal adjustment circuit 10 can be connected, for example, as a half circuit of a transimpedance amplifier (TIA) between the mixer 14 and the receiver filter 16. And this TIA is applicable to a differential transmission scheme, so it further includes the other half circuit, which has a circuit architecture symmetric to that of the signal adjustment circuit 10. Therefore, obviously, the first input terminal is connected to the mixer 14 to receive the first input signal Sin1, and the first output terminal is connected to the receiver filter 16 to output the first output signal Sout1.

[0023] In addition, the peak detector 12 is connected to the first output node N1 to receive the first detection signal Sd1 and detect the peak of the first detection signal Sd1. It should be noted that the peak detector 12 can convert an AC signal into a DC voltage level and then transmit it to the comparator circuit for comparison. Therefore, it can output a high-level signal when the first detection signal Sd1 exceeds a preset voltage value, so as to detect whether the first detection signal Sd1 meets the predetermined power input range. And the resistors R1 and R2 can be designed to have a first predetermined ratio, aiming to select an appropriate intermediate gain in cooperation with the overall gain (the aforementioned first gain) of the TIA, so as to provide an appropriate first detection signal Sd1 to the peak detector 12. In other words, the resistors R1 and R2 with a first predetermined ratio of resistance values can make the first detection signal Sd1 have a second gain relative to the first input signal Sin1 and within the predetermined power input range of the peak detector 12.

[0024] In addition, it should be noted that the first gain (hereinafter referred to as Gain1) depends on the equivalent impedance (hereinafter referred to as Rmix) of the front-end circuit including the mixer 14, and the resistance values of the resistors R1 and R2.

[0025] The following gives an example to illustrate the determination method of the resistance values of the resistors R1 and R2.

[0026] If the requirement is to set a peak detector at the output end of the TIA, and its predetermined power input range is +10 dBm, and the overall gain (Gain1) of the TIA is 28 dB, then it is equivalently required to provide a first detection signal Sd1 with a second gain (hereinafter referred to as Gain2) of 18 dB at the first output node N1.

[0027] Therefore, it is necessary to select an appropriate ratio of the resistors R1 and R2 to satisfy the following formulas (1) and (2):

[0028]

[0029]

[0030] Among them, assuming that the equivalent impedance Rmix observed by the TIA at one end of the mixer 14 is 400 Ohm, the resistors R1 and R2 can be obtained from the following equations (3)-(5):

[0031]

[0032]

[0033] R2 = 10.048 - 3.177 = 6.871 kOhm... Equation (5).

[0034] As can be seen from the above equations, the signal adjustment circuit 10 provided by the present invention can design the resistance values of the resistors R1 and R2 for the TIA, so that the first detection signal Sd1 has an appropriate second gain relative to the first input signal Sin1 and is within the predetermined power input range of the peak detector 12.

[0035] Figure 2A Another circuit layout diagram of the signal adjustment circuit according to the first embodiment of the present invention Figure 2B Another circuit layout diagram of the signal adjustment circuit according to the first embodiment of the present invention.

[0036] In Figure 2A In the embodiment, the resistor R1 can be replaced by a variable resistor R1', the resistor R2 can be replaced by a variable resistor R2', and the signal adjustment circuit 10 further includes a control circuit 104, which is configured to control the first gain and the second gain by controlling the resistance values of the variable resistors R1' and R2', so that after the first output signal Sout1 changes, the first detection signal Sd1 is still within the predetermined power input range.

[0037] In addition, as Figure 2B shown, the variable resistor R1' includes switches S1, S2 and resistors R11, R12 with different resistance values, and the switches S1, S2 are respectively connected in series with the resistors R11, R12. Similarly, the variable resistor R2' includes switches S3, S4 and resistors R21, R22 with different resistance values, and the switches S3, S4 are respectively connected in series with the resistors R21, R22.

[0038] In this embodiment, the control circuit 104 is configured to control the switches S1, S2, S3, S4 to be turned on or off to determine the first gain and the second gain.

[0039] For example, if the TIA itself can switch different overall gains (the first gain), the resistance values of the appropriate resistors R1 and R2 can also be designed to apply to the same peak detector 12. In other words, the first detection signal Sd1 is still within the same predetermined power input range, without the need to use different peak detectors 12, nor to add additional preamplifiers or attenuators.

[0040] The following is an example based on Figure 2A and 2B 's signal adjustment circuit.

[0041] If the requirement is to set a peak detector at the output of the TIA, with a predetermined power input range of +10 dBm, and the overall gain (Gain1) of the TIA can be switched between 28 dB and 22 dB, then equivalently, a first detection signal Sd1 with a second gain (hereinafter referred to as Gain2) of 18 dB and 12 dB needs to be provided at the first output node N1.

[0042] With the above conditions, the resistance values of resistors R1 and R2 to be used can be calculated respectively according to the above formulas (1)-(5) when the second gain is 18 dB and 12 dB. Furthermore, through the control of the control circuit 104, after the first output signal Sout1 is changed due to gain adjustment, the second gain can be correspondingly adjusted so that the first detection signal Sd1 is still within the predetermined power input range. Therefore, there is no need to use different peak detectors 12, nor is it necessary to add an additional preamplifier or attenuator.

[0043] [Second Embodiment]

[0044] Figure 3 FIG. is a circuit layout diagram of the signal adjustment circuit of the second embodiment of the present invention applied to the receiving end circuit.

[0045] Referring to Figure 3 shown, the second embodiment of the present invention provides a signal adjustment circuit 30, which is applicable to a peak detector 32. The signal adjustment circuit 30 includes a first amplifier 300 and a first feedback circuit 302. The first feedback circuit 302 includes a capacitor C1, resistors R1 and R2. It should be noted that the architecture of the signal adjustment circuit 30 is basically the same as that of Figure 1 's signal adjustment circuit 10, so the repeated description is omitted.

[0046] The difference is that Figure 3 's signal adjustment circuit 30 further includes a resistor R3, one end of which is used to receive the first input signal Sin1', and the other end is connected to the first input terminal (left positive (+) terminal) of the first amplifier 300.

[0047] It should be noted that the signal adjustment circuit 30 of this embodiment is applied to the receiving end circuit 3, and the receiving end circuit 3 further includes an antenna 31, a peak detector 32, a low noise amplifier (LNA) 33, a mixer 34, a transimpedance amplifier 35, and an analog-to-digital converter (ADC) 36. The signal adjustment circuit 30 can be connected between the transimpedance amplifier 35 and the analog-to-digital converter 36, for example, as a half circuit of the Rx baseband filter. Similarly, in order to be applicable to the differential transmission scheme, the Rx baseband filter further includes the other half circuit, which has a circuit architecture symmetric to that of the signal adjustment circuit 30.

[0048] In this embodiment, the overall gain (the first gain Gain1) of the Rx baseband filter depends on the resistance values of resistors R1, R2, and R3, as shown in the following formula (6):

[0049]

[0050] In addition, it should be noted that the resistors R1 and R2 in this embodiment can be similar to Figure 2A using a control circuit to control a variable resistor, or using Figure 2B a control circuit to switch a switch. The present invention is not limited thereto.

[0051] The following gives an example to illustrate the determination method of the resistance values of the resistors R1 and R2 in this embodiment.

[0052] If the requirement is to set a peak detector at the output end of the Rx baseband filter, and its predetermined power input range is +10 dBm, and the overall gain (Gain1) of the Rx baseband filter is 24 dB, then equivalently, a first detection signal Sd1' with a second gain (hereinafter referred to as Gain2) of 14 dB needs to be provided at the first output node N1, so that the first detection signal Sd1' input to the peak detector 32 is 0 dBm.

[0053] Assuming that the resistance value of resistor R3 is 1 kOhm, the sum of the resistors R1 and R2 can be calculated from formula (6), as shown in the following formula (7):

[0054]

[0055] Next, an appropriate ratio of the resistors R1 and R2 needs to be selected to make the first detection signal Sd1' input to the peak detector 32 be 0 dBm, so as to equivalently make the peak detector set at the output end of the Rx baseband filter receive a signal of +10 dBm. Therefore, the resistors R1 and R2 can be obtained from the following formulas (8)-(10):

[0056]

[0057]

[0058] R2 = 15.849 - 5.011 = 10.838 k Ohm... Equation (10).

[0059] As can be seen from the above equations, the signal adjustment circuit 30 provided by the present invention can be used in the receiving end circuit 3, and the resistance values of the resistors R1 and R2 can be designed for the receiving end baseband filter, so that the first detection signal Sd1' has an appropriate second gain relative to the first input signal Sin1', and within the predetermined power input range of the peak detector 12.

[0060] [Third Embodiment]

[0061] Figure 4 It is a block diagram of a receiving end circuit according to the third embodiment of the present invention. Figure 5 It is a circuit architecture diagram of a transimpedance amplifier and a receiving end baseband filter of a receiving end circuit according to the third embodiment of the present invention.

[0062] Refer to Figure 4 As shown, the third embodiment of the present invention provides a receiving end circuit 4, which includes an antenna 41, peak detectors 421, 422, 423, 424, an LNA 43, a mixer 44, a transimpedance amplifier 45, a receiving end baseband filter 46, an ADC 47, and a gain automatic control circuit 48.

[0063] As Figure 5 shown, the half circuit of the transimpedance amplifier 45 is connected to the mixer 44, the half circuit of the receiving end baseband filter 46 is connected to the half circuit of the transimpedance amplifier 45, and similarly, in order to be applicable to the differential transmission scheme, both the transimpedance amplifier 45 and the receiving end baseband filter 462 also include the other half circuit, having a symmetrical circuit architecture.

[0064] The transimpedance amplifier 45 includes the signal adjustment circuit mentioned in the foregoing embodiment, for example Figure 2A the signal adjustment circuit 10, which includes an amplifier 450, a feedback circuit 452, and a control circuit 454. The amplifier 450 is used to amplify the first input signal Sin1" to output a first output signal Sout1". The feedback circuit 452 includes a capacitor C1", variable resistors R1" and R2". The amplifier 450 and the feedback circuit 452 have the same circuit architecture as Figure 2A that shown, so the repeated description is omitted.

[0065] The control circuit 454 is used to control the variable resistors R1" and R2" to determine the first gain of the first output signal Sout1" relative to the first input signal Sin1", and the second gain of the first detection signal Sd1" relative to the first input signal Sin1". The peak detector 421 is connected to the first output node N1 to receive the first detection signal Sd1", has a first predetermined power input range and is used to detect the peak of the first detection signal Sd1". Similarly, the control circuit 454 controls the resistance values of the variable resistors R1" and R2" to have a first predetermined ratio, so that the first detection signal Sd1" is within the first predetermined power input range.

[0066] The receiving-end baseband filter 46 includes a second signal adjustment circuit, which includes a resistor R5", an amplifier 460 and a feedback circuit 462. One end of the resistor R5" is connected to the first input terminal of the amplifier 460. The amplifier 460 is used to amplify the first output signal Sout1" to output a second output signal Sout2. The feedback circuit 462 includes a capacitor C2", variable resistors R3" and R4". The circuit architectures of the amplifier 460 and the feedback circuit 462 are the same, so repeated descriptions are omitted. Figure 2A The circuit architectures of the amplifier 460 and the feedback circuit 462 are the same, so repeated descriptions are omitted.

[0067] Among them, the control circuit 464 is used to control the variable resistors R3" and R4" to determine the third gain of the second output signal Sout2 relative to the first output signal Sout1", and the fourth gain of the second detection signal Sd2" relative to the first output signal Sout1". The peak detector 423 is connected to the second output node N2 to receive the second detection signal Sd1", has a second predetermined power input range and is used to detect the peak of the second detection signal Sd1". Similarly, the control circuit 464 controls the resistance values of the variable resistors R3" and R4" to have a second predetermined ratio, so that the second detection signal Sd1" is within the second predetermined power input range. In another embodiment, the control circuit 454 and the control circuit 464 can be integrated into the same control circuit to control the resistance values of the variable resistors R1", R2", R3" and R4", but the present invention is not limited thereto.

[0068] In the receiving-end circuit 4, the LNA 43 has adjustable gain. The LNA 43 receives the received signal from the antenna, amplifies it and provides a receiving-end signal and inputs it to the mixer 44. The mixer 44 is connected to the LNA 43 and the transimpedance amplifier 45 to mix the receiving-end signal, and after down-conversion, provides the first input signal Sin1" to the transimpedance amplifier 45. The analog-to-digital converter is connected to the receiving-end baseband filter 46 to receive the second output signal, and performs analog-to-digital conversion on the second output signal Sout2 to generate a digital signal.

[0069] The automatic gain control circuit 48 of the receiving end circuit 4 is connected to the control circuits 454, 464, the peak detectors 421, 422, 423, 424, and the LNA 43, and is configured to control the control circuits 454, 464, and the LNA 43 according to the detection results of the peak detectors 421, 422, 423, 424.

[0070] More specifically, in this embodiment, taking the peak detectors 421, 422, 423, 424 as 1-bit peak detectors as an example, they only output high and low levels to represent the detection results. And in this embodiment, the peak detectors 421, 423 are designed to detect that the output powers of the transimpedance amplifier 45 and the receiving end baseband filter are both +10 dBm. In other embodiments, the peak detector can be implemented by a multi-bits peak detector, but the present invention is not limited thereto.

[0071] In this embodiment, when the detection results of both peak detectors 421, 423 are high level, it means that the signal gain is too large and the gain needs to be adjusted by a large amplitude. For example, the automatic gain control circuit 48 can be configured to correspondingly adjust the overall gains of the LNA 43 and the receiving end baseband filter 46 when obtaining this detection result. Among them, the adjustment method of the overall gain of the receiving end baseband filter 46 has been described in the above embodiment, so it is omitted here.

[0072] When the detection result of the peak detector 421 is high level and the detection result of the peak detector 423 is low level, it means that coexistence interference may occur at this time and there are large outband spurs. Then the automatic gain control circuit 48 can be configured to correspondingly reduce the overall gains of the LNA 43 and the transimpedance amplifier 45 when obtaining this detection result. Among them, the adjustment method of the overall gain of the transimpedance amplifier 45 has been described in the above embodiment, so it is omitted here.

[0073] When the detection result of the peak detector 421 is low level and the detection result of the peak detector 423 is high level, or when the detection results of both peak detectors 421, 423 are low level, it means that the overall gain of the receiving end baseband filter 46 needs to be finely adjusted at this time to adjust its output power to an appropriate range.

[0074] Furthermore, if more peak detectors are set, for example Figure 5For the peak detectors 422 and 424, the gain can be adjusted more precisely based on the detection results. For example, when the output of the peak detector 422 is at a high level, it can be calculated that the input power to the LNA 43 is greater than a specific power. Based on the information from the peak detectors 422 and 424, the input power level of the LNA 43 can be determined, enabling the gain automatic adjustment circuit 48 to control the control circuits 454 and 464 and the LNA 43 to quickly switch to a suitable gain.

[0075] [Advantages of the Embodiment]

[0076] One of the advantages of the present invention is that the signal adjustment circuit provided by the present invention and the receiving end circuit using the same can be combined with appropriate designs of the transimpedance amplifier or the baseband filter in the receiving end circuit. Without increasing the area, an additional attenuator or preamplifier is not required and it is applicable to the receiving end peak detector, thereby reducing the mismatch caused by using the above-mentioned additional components.

[0077] The content disclosed above is only the preferred feasible embodiment of the present invention, and does not limit the scope of the patent application of the present invention. Therefore, all equivalent technical changes made by using the description and drawings of the present invention are included in the scope of the patent application of the present invention.

[0078] Symbol Description

[0079] 3, 4: Receiving end circuit

[0080] 10, 30: Signal adjustment circuit

[0081] 12, 32, 421, 422, 423, 424: Peak detector

[0082] 14, 34, 44: Mixer

[0083] 16: Receiving end filter

[0084] 31, 41: Antenna

[0085] 33, 43: Low noise amplifier

[0086] 35, 45: Transimpedance amplifier

[0087] 36, 47: Analog-to-digital converter

[0088] 46: Receiving end baseband filter

[0089] 48: Gain automatic control circuit

[0090] 100: First amplifier

[0091] 102: First feedback circuit

[0092] 104, 454, 464: Control circuit

[0093] 302: First feedback circuit

[0094] 450, 460: Amplifiers

[0095] 452, 462: Feedback circuits

[0096] C1, C1", C2": Capacitors

[0097] N1: First output node

[0098] N2: Second output node

[0099] R1, R1", R2, R2", R3, R3", R4", R5", R11, R12, R21, R22: Resistors

[0100] R1', R2': Variable resistors

[0101] S1, S2, S3, S4: Switches

[0102] Sd1, Sd1', Sd1": First detection signals

[0103] Sd2": Second detection signal

[0104] Sin1, Sin1', Sin1": First input signals

[0105] Sout1, Sout1', Sout1": First output signals

[0106] Sout2: Second output signal

Claims

1. A signal adjustment circuit, applicable to a peak detector, the signal adjustment circuit comprises: A first amplifier, including a first input terminal and a first output terminal, wherein the first input terminal receives a first input signal, and the first amplifier is configured to amplify the first input signal to output a first output signal from the first output terminal; and A first feedback circuit, including: A first capacitor, connected between the first input terminal and the first output terminal; A first resistor, connected between the first input terminal and a first output node; and A second resistor, connected between the first output node and the first output terminal, wherein the first feedback circuit is configured to determine a first gain of the first output signal; wherein the peak detector is connected to the first output node to receive a first detection signal and detect a peak of the first detection signal; wherein the peak detector has a predetermined power input range, and the first resistor and the second resistor have a first predetermined ratio, such that the first detection signal has a second gain relative to the first input signal and within the predetermined power input range.

2. The signal adjustment circuit according to claim 1, wherein the signal adjustment circuit serves as a first half circuit of a first transimpedance amplifier and is connected between a mixer and a receiving end filter, and the first transimpedance amplifier further includes a second half circuit having a circuit architecture symmetric to that of the first half circuit to be applicable to a differential transmission scheme.

3. The signal adjustment circuit according to claim 2, wherein the first gain depends on a first equivalent impedance of a front-end circuit including the mixer, the first resistor, and the second resistor.

4. The signal adjustment circuit according to claim 2, wherein, the first input terminal is connected to the mixer to receive the first input signal, and the first output terminal is connected to the receiving end filter to output the first output signal.

5. The signal adjustment circuit according to claim 1, wherein the first resistor is a first variable resistor, the second resistor is a second variable resistor, and the signal adjustment circuit further includes a control circuit configured to control the first gain and the second gain by controlling the resistance values of the first variable resistor and the second variable resistor, such that after the first output signal changes, the first detection signal is still within the predetermined power input range.

6. The signal adjustment circuit according to claim 5, wherein, the first variable resistor includes a plurality of first switches and a plurality of third resistors having different resistance values, and the first switches are respectively connected in series with the third resistors, wherein the second variable resistor includes a plurality of second switches and a plurality of fourth resistors having different resistance values, and the first switches are respectively connected in series with the third resistors, wherein the control circuit is configured to control the first switches and the second switches to be turned on or off to determine the first gain and the second gain.

7. The signal adjustment circuit according to claim 1, further includes a fifth resistor, one end of which is configured to receive the first input signal and the other end of which is connected to the first input terminal.

8. The signal adjustment circuit as claimed in claim 7, wherein the signal adjustment circuit is connected between the second transimpedance amplifier and the analog-to-digital converter as the third half-circuit of the receiving-end baseband filter, and the receiving-end baseband filter further includes a fourth half-circuit having a circuit architecture symmetric to that of the third half-circuit to be applicable to a differential transmission scheme.

9. A receiving-end circuit comprising: A transimpedance amplifier including a first signal adjustment circuit, the first signal adjustment circuit including: A first amplifier including a first input terminal and a first output terminal, wherein the first input terminal receives a first input signal, and the first amplifier is configured to amplify the first input signal to output a first output signal from the first output terminal; A first feedback circuit including: A first capacitor connected between the first input terminal and the first output terminal; A first variable resistor connected between the first input terminal and a first output node; and A second variable resistor connected between the first output node and the first output terminal; and A first control circuit configured to control the resistance values of the first variable resistor and the second variable resistor to determine a first gain of the first output signal relative to the first input signal and a second gain of a first detection signal relative to the first input signal; and A first peak detector connected to the first output node to receive the first detection signal, having a first predetermined power input range and configured to detect the peak of the first detection signal, wherein the first control circuit controls the resistance values of the first variable resistor and the second variable resistor to have a first predetermined ratio such that the first detection signal is within the first predetermined power input range.

10. The receiving-end circuit as claimed in claim 9, further comprising: A receiving-end baseband filter including a second signal adjustment circuit, the second signal adjustment circuit including: A first resistor having one end connected to the first output terminal; and A second amplifier including a second input terminal and a second output terminal, wherein the second input terminal is connected to the first output terminal through the first resistor to receive the first output signal, and the second amplifier is configured to amplify the first output signal to output a second output signal from the second output terminal; and A second feedback circuit including: A second capacitor connected between the second input terminal and the second output terminal; A third variable resistor connected between the second input terminal and a second output node; and A fourth variable resistor connected between the second output node and the second output terminal, wherein the second feedback circuit is configured to determine a third gain of the second output signal relative to the first output signal; and A second control circuit configured to control the resistance values of the third variable resistor and the fourth variable resistor to determine a second gain of a second detection signal relative to the first output signal; A second peak detector connected to the second output node to receive the second detection signal, having a second predetermined power input range and configured to detect the peak of the second detection signal, wherein the second control circuit controls the resistance values of the third variable resistor and the fourth variable resistor to have a second predetermined ratio such that the second detection signal is within the second predetermined power input range.

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