A broadband power amplifier input control circuit

Abstract

The present application relates to the technical fields of wideband power amplifier, and especially relates to a wideband power amplifier input control circuit, which comprises: a first operational amplifier circuit, a same-phase input end of which is connected with a related voltage signal of a wideband power amplifier output signal, an opposite-phase input end of which is connected with a voltage signal corresponding to a preset voltage threshold for amplitude stabilization, and an output end of which outputs a voltage signal for amplitude stabilization; a waveband selection circuit, an input end of which is connected with a preset waveband selection control signal, selects and outputs a segmented preset voltage signal corresponding to a frequency waveband of the output signal; a second operational amplifier circuit, a same-phase input end of which is connected with the segmented preset voltage signal, an opposite-phase input end of which is connected with the voltage signal for amplitude stabilization, and an output end of which outputs an attenuation value control voltage signal; and an electrically tunable attenuator, an input end of which is connected with the attenuation value control voltage signal, and an output end of which outputs a working radio frequency signal to the wideband power amplifier. The present application can solve the technical problem of unstable power output amplitude of the wideband power amplifier.

Description

Technical Field

[0001] This invention relates to the field of broadband power amplifier technology, and more particularly to a broadband power amplifier input control circuit. Background Technology

[0002] Broadband power amplifiers have different gains at different operating frequencies, and the wider the operating bandwidth, the greater the gain difference. For example, for the ultra-shortwave band spanning three octaves (100MHz to 500MHz), the gain difference of broadband power amplifiers operating in this band can be as much as 20 times. Therefore, the output power of broadband power amplifiers may experience significant overshoot, meaning that the output power at the initial moment is much greater than the rated output power. This will pose a great safety hazard to various components in the system containing the broadband amplifier, such as synthesizers, impedance matching circuits, switches, and transmitting antennas, and will greatly affect the reliability of the entire system.

[0003] See Figure 1 , Figure 1 This is an example diagram of segmented filtering processing of the signal output from a broadband power amplifier in existing technology. Figure 1 In this process, the original radio frequency (RF) signal is input to a broadband power amplifier via an electrically adjustable attenuator. The electrically adjustable attenuator has four ports: the original RF signal input, the power supply input, the control voltage signal input, and the working RF signal output. It attenuates the original RF signal according to the attenuation value corresponding to the control voltage signal to obtain the working RF signal. In existing technologies, the control voltage signal is typically 0; therefore, the electrically adjustable attenuator attenuates the original RF signal according to its maximum attenuation value. The working RF signal is amplified by the broadband power amplifier, then input to a band-segmented filter for filtering. After the power level is detected by a power detector, a high-power RF signal is output. The band-segmented filter filters the working RF signal for the corresponding band based on a preset band selection signal.

[0004] Existing technologies only perform frequency segmentation filtering on the output signal of broadband power amplifiers, but do not solve the problem of unstable power output amplitude of broadband power amplifiers. Therefore, it is urgent to propose corresponding technical solutions to solve this technical problem. Summary of the Invention

[0005] Based on the above analysis, the present invention aims to provide an input control circuit for a broadband power amplifier, thereby solving the technical problem of unstable power output amplitude in existing broadband power amplifiers.

[0006] The technical solution provided by this invention is:

[0007] An embodiment of the present invention provides a broadband power amplifier input control circuit, comprising:

[0008] The first operational amplifier circuit has a non-inverting input terminal connected to a related voltage signal of the output signal of the broadband power amplifier, an inverting input terminal connected to a voltage signal corresponding to a preset amplitude stabilization voltage threshold, and an output terminal that outputs an amplitude stabilization voltage signal whose change direction is consistent with the change direction of the related voltage signal when the output signal increases to the point that the voltage value of the related voltage signal is greater than the amplitude stabilization voltage threshold.

[0009] The band selection circuit has a preset band selection control signal input, selects and outputs a segmented preset voltage signal corresponding to the frequency band of the output signal.

[0010] The second operational amplifier circuit has the segmented preset voltage signal connected to its non-inverting input terminal and the amplitude stabilization voltage signal connected to its inverting input terminal, and outputs an attenuation control voltage signal whose changing direction is opposite to that of the amplitude stabilization voltage signal.

[0011] An electrically adjustable attenuator is connected to the attenuation control voltage signal at its input terminal, and outputs a working radio frequency signal obtained by attenuating the original radio frequency signal with an attenuation value whose change direction is consistent with the change direction of the relevant voltage signal, and sends the signal to the broadband power amplifier.

[0012] Preferably, the non-inverting input of the first operational amplifier circuit is connected to one output of a power detector, and the power detector detects and outputs the relevant voltage signal.

[0013] Preferably, the circuit further includes a third operational amplifier circuit; the non-inverting input of the first operational amplifier circuit is connected to an output of the power detector through the third operational amplifier circuit; comprising:

[0014] The non-inverting input of the third operational amplifier circuit is connected to one output of the power detector, and the output is connected to the non-inverting input of the first operational amplifier circuit.

[0015] The non-inverting input terminal of the first operational amplifier circuit is connected to the output terminal of the third operational amplifier circuit.

[0016] Preferably, the third operational amplifier circuit includes:

[0017] The third operational amplifier, the first resistor, the second resistor, the third resistor, and the first capacitor;

[0018] The non-inverting input of the third operational amplifier is connected to one output of the power detector and one end of the first resistor, and the other end of the first resistor is grounded.

[0019] The inverting input terminal of the third operational amplifier is connected to one end of the second resistor, one end of the third resistor, and one end of the first capacitor;

[0020] The other end of the second resistor and the other end of the first capacitor are both connected to the output terminal of the third operational amplifier, and the other end of the third resistor is grounded.

[0021] Preferably, the first operational amplifier circuit includes:

[0022] First operational amplifier, fourth resistor, fifth resistor, sixth resistor, seventh resistor, eighth resistor, first potentiometer, and second capacitor;

[0023] One end of the fourth resistor is connected to the output terminal of the third operational amplifier, and the other end is connected to the non-inverting input terminal of the first operational amplifier;

[0024] One end of the fifth resistor is connected to the non-inverting input of the first operational amplifier, and the other end is grounded;

[0025] One end of the sixth resistor, the eighth resistor, and the second capacitor is connected to the inverting input terminal of the first operational amplifier, and the other end of the eighth resistor and the other end of the second capacitor are connected to the output terminal of the first operational amplifier.

[0026] The other end of the sixth resistor is connected to one end of the seventh resistor and one end of the first potentiometer and the middle terminal. The other end of the seventh resistor is grounded, and the other end of the first potentiometer is connected to a preset power signal for providing a voltage signal corresponding to the preset voltage threshold.

[0027] Preferably, the band selection circuit includes:

[0028] Numerical control analog switch integrated circuit, at least two potentiometers;

[0029] The numerical control signal input terminal of the numerical control analog switch integrated circuit is connected to the band selection control signal, one end of the switch is connected to one end of each of at least two potentiometers, and the other end of the switch is the output terminal;

[0030] The middle terminal of each of the at least two potentiometers is grounded to the other terminal.

[0031] Preferably, the second operational amplifier circuit includes: a second operational amplifier, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, and a third capacitor;

[0032] One end of the tenth resistor and the eleventh resistor are connected to the output terminal of the first operational amplifier, and the other end of the tenth resistor is grounded;

[0033] The other end of the eleventh resistor, one end of the twelfth resistor, and one end of the third capacitor are connected to the inverting input of the second operational amplifier;

[0034] One end of the ninth resistor is connected to a power supply, and the other end is connected to the non-inverting input terminal of the second operational amplifier;

[0035] The non-inverting input of the second operational amplifier is connected to the other end of the on / off switch of the digitally controlled analog switch integrated circuit.

[0036] Preferably, the first operational amplifier, the second operational amplifier, and the third operational amplifier are three operational amplifiers on a single quad operational amplifier integrated circuit LM124; or,

[0037] The first operational amplifier, the second operational amplifier, and the third operational amplifier are three single-channel operational amplifier integrated circuits; or,

[0038] The first operational amplifier, the second operational amplifier, and the third operational amplifier are implemented using two dual-channel operational amplifier integrated circuits.

[0039] Preferably, the numerical control analog switch integrated circuit is a differential four-channel analog switch integrated circuit CD4052.

[0040] Preferably, the preset power signal voltage value is 12V.

[0041] In the technical solution provided by the embodiments of the present invention, the input power of the input broadband power amplifier is controlled, thereby controlling the output power of its output signal. This is mainly achieved by: when the output signal of the broadband power amplifier is small, its related voltage signal is small. If it does not exceed the preset voltage threshold, it indicates that the output signal amplitude has not overshooted. Once the output signal of the broadband power amplifier is large and the corresponding related voltage signal exceeds the preset voltage threshold, the first operational amplifier circuit is activated, or the entire broadband power amplifier input control circuit is activated, and an amplitude stabilization voltage signal is output.

[0042] Furthermore, in the embodiments of the present invention, the frequency bands of the original radio frequency signal are pre-divided into multiple different frequency bands. For each frequency band, a different segmented preset voltage signal is preset. When the band selection circuit receives the preset band selection control signal, it selects the segmented preset voltage signal corresponding to the frequency band of the output signal and outputs it. Since the segmented preset voltage signal is set for different frequency bands of the output signal, the same attenuation value is not used for attenuation. Instead, for higher frequency band signals, since the corresponding gain is lower, a relatively smaller attenuation value is used for attenuation; for lower frequency band signals, since the corresponding gain is higher, a relatively larger attenuation value is used for attenuation. This effectively controls the amplitude variation of the input signal of the broadband power amplifier to prevent it from becoming too large and keeps it basically stable near its normal output power.

[0043] Furthermore, the second operational amplifier circuit is connected to a segmented preset voltage signal and an amplitude stabilization voltage signal. The voltage value corresponding to the segmented preset voltage signal is fixed, while the amplitude stabilization voltage signal changes with the voltage value corresponding to the relevant voltage signal or the output signal, and the direction of change is consistent. Therefore, the direction of change of the attenuation control voltage signal output by the second operational amplifier circuit is opposite to the direction of change of the amplitude stabilization voltage signal. Based on the characteristics of the electrically adjustable attenuator itself, the direction of change of its attenuation value is opposite to the direction of change of the attenuation control voltage signal. Therefore, the direction of change of the obtained attenuation value is consistent with the direction of change of the amplitude stabilization voltage signal or the relevant voltage signal. That is, as the output signal voltage amplitude increases, the attenuation value of the electrically adjustable attenuator also increases. Correspondingly, the power of the input signal of the broadband power amplifier decreases, thereby effectively controlling the power of the output signal of the broadband power amplifier to prevent it from becoming too large and effectively reducing the possibility of overshoot in the output signal.

[0044] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0045] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0046] Figure 1 This is an example diagram of segmented filtering processing of the signal output from a broadband power amplifier in existing technology;

[0047] Figure 2 This is a schematic diagram of the input control circuit structure of the broadband power amplifier in an embodiment of the present invention. Figure 1 ;

[0048] Figure 3 This is a schematic diagram of the radio frequency amplifier circuit in an embodiment of the present invention;

[0049] Figure 4 This is a schematic diagram of the input control circuit structure of the broadband power amplifier in an embodiment of the present invention. Figure 2 ;

[0050] Figure 5 This is a specific example diagram of the broadband power amplifier input control circuit in an embodiment of the present invention. Detailed Implementation

[0051] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and, together with the embodiments of the present invention, serve to illustrate the principles of the present invention.

[0052] An embodiment of the present invention provides a broadband power amplifier input control circuit, see below. Figure 2 , Figure 2 This is a schematic diagram of the input control circuit structure of the broadband power amplifier in an embodiment of the present invention. Figure 1 The control circuit may include:

[0053] The first operational amplifier circuit 201 has a non-inverting input terminal connected to a related voltage signal of the output signal of the broadband power amplifier, an inverting input terminal connected to a voltage signal corresponding to a preset voltage threshold, and an output terminal that outputs an amplitude-stabilizing voltage signal whose changing direction is consistent with the changing direction of the related voltage signal when the output signal increases to the point that the voltage value of the related voltage signal is greater than the voltage threshold.

[0054] The band selection circuit 202 has a preset band selection control signal input, selects and outputs a segmented preset voltage signal corresponding to the frequency band of the output signal.

[0055] The second operational amplifier circuit 203 has the segmented preset voltage signal connected to its non-inverting input terminal and the amplitude stabilization voltage signal connected to its inverting input terminal, and outputs an attenuation control voltage signal whose changing direction is opposite to that of the amplitude stabilization voltage signal.

[0056] The electrically adjustable attenuator 204 has the attenuation value control voltage signal connected to its input terminal, and outputs a working radio frequency signal obtained by attenuating the original radio frequency signal with an attenuation value whose change direction is consistent with the change direction of the relevant voltage signal, and sends it to the broadband power amplifier.

[0057] In this embodiment of the invention, exemplarily, the broadband power amplifier is a GFG2189 power amplifier, the bandgap filter is a GFL2152 filter, and the power detector is a GCO2151 power detector. The technical solution provided by this embodiment controls the input power of the broadband power amplifier, thereby controlling the output power of its output signal. This mainly involves: when the output signal of the broadband power amplifier is small, its related voltage signal is also small. If it does not exceed a preset voltage threshold, it indicates that the output signal amplitude has not overshooted. Once the output signal of the broadband power amplifier is large, and the corresponding related voltage signal exceeds the preset voltage threshold, the first operational amplifier circuit is activated, or in other words, the entire broadband power amplifier input control circuit is activated, outputting a voltage signal for amplitude stabilization.

[0058] Furthermore, in the embodiments of the present invention, the frequency bands of the original radio frequency signal are pre-divided into multiple different frequency bands. For each frequency band, a different segmented preset voltage signal is preset. When the band selection circuit receives the preset band selection control signal, it selects the segmented preset voltage signal corresponding to the frequency band of the output signal and outputs it. Since the segmented preset voltage signal is set for different frequency bands of the output signal, the same attenuation value is not used for attenuation. Instead, for higher frequency band signals, since the corresponding gain is lower, a relatively smaller attenuation value is used for attenuation; for lower frequency band signals, since the corresponding gain is higher, a relatively larger attenuation value is used for attenuation. This effectively controls the amplitude variation of the input signal of the broadband power amplifier to prevent it from becoming too large and keeps it basically stable near its normal output power.

[0059] Furthermore, the second operational amplifier circuit is connected to a segmented preset voltage signal and an amplitude stabilization voltage signal. The voltage value corresponding to the segmented preset voltage signal is fixed, while the amplitude stabilization voltage signal changes with the voltage value corresponding to the relevant voltage signal or the output signal, and the direction of change is consistent. Therefore, the direction of change of the attenuation control voltage signal output by the second operational amplifier circuit is opposite to the direction of change of the amplitude stabilization voltage signal. Based on the characteristics of the electrically adjustable attenuator itself, the direction of change of its attenuation value is opposite to the direction of change of the attenuation control voltage signal. Therefore, the direction of change of the obtained attenuation value is consistent with the direction of change of the amplitude stabilization voltage signal or the relevant voltage signal. That is, as the output signal voltage amplitude increases, the attenuation value of the electrically adjustable attenuator also increases. Correspondingly, the power of the input signal of the broadband power amplifier decreases, thereby effectively controlling the power of the output signal of the broadband power amplifier to prevent it from becoming too large and effectively reducing the possibility of overshoot in the output signal.

[0060] See Figure 3 , Figure 3 This is a schematic diagram of the radio frequency amplifier circuit in an embodiment of the present invention. The input terminal of the broadband power amplifier is connected to the output terminal of the broadband power amplifier input control circuit, and the output terminal is connected to the input terminal of the band-segmentation filter. The first input terminal of the band-segmentation filter is connected to the output terminal of the broadband power amplifier, the second input terminal receives a preset band selection control signal, and the output terminal is connected to the input terminal of the power detector. The input terminal of the power detector is connected to the output terminal of the band-segmentation filter, the first output terminal is connected to the input terminal of the broadband power amplifier input control circuit, and the second output terminal outputs a power signal. The input terminal of the broadband power amplifier input control circuit is connected to the first output terminal of the power detector, and the output terminal is connected to the input terminal of the broadband power amplifier. Figure 3 As shown, the input control circuit of the broadband power amplifier in this invention is a feedback circuit.

[0061] In practical applications, when the power detection voltage signal of the broadband power amplifier output signal detected by the power detector is relatively large, such as around 0.5V, it can be used as the aforementioned related voltage signal. In this case, the non-inverting input of the first operational amplifier circuit can be directly connected to one output terminal (first output terminal) of the power detector. In practical applications, the power detection voltage signal is usually small, such as only around 0.02V. Therefore, in practical applications, a third operational amplifier circuit can be further added to the broadband power amplifier input control circuit. The non-inverting input of the first operational amplifier circuit is connected to one output terminal (first output terminal) of the power detector through the third operational amplifier circuit, and the power detector detects and outputs the related voltage signal. See also... Figure 4 , Figure 4 This is a schematic diagram of the input control circuit structure of the broadband power amplifier in an embodiment of the present invention. Figure 2 The non-inverting input of the third operational amplifier circuit 401 is connected to one output (first output) of the power detector (not shown), and the output is connected to the non-inverting input of the first operational amplifier circuit 201; the non-inverting input of the first operational amplifier circuit 201 is connected to the output of the third operational amplifier circuit 401.

[0062] See Figure 5 , Figure 5 This is a specific example diagram of the input control circuit of the broadband power amplifier in an embodiment of the present invention, wherein the electrically adjustable attenuator is not shown. Figure 5 In the circuit, the third operational amplifier circuit 401 may include: a third operational amplifier N2A, a first resistor R1, a second resistor R2, a third resistor R3, and a first capacitor C1;

[0063] The non-inverting input of the third operational amplifier N2A is connected to one output of the power detector and one end of the first resistor R1, while the other end of the first resistor R1 is grounded.

[0064] The inverting input terminal of the third operational amplifier N2A is connected to one end of the second resistor R2, one end of the third resistor R3, and one end of the first capacitor C1.

[0065] The other end of the second resistor R2 and the other end of the first capacitor C1 are both connected to the output of the third operational amplifier N2A, and the other end of the third resistor R3 is grounded.

[0066] The power input terminal of the third operational amplifier N2A is connected to a power signal with a voltage of 12V, and the ground terminal is grounded.

[0067] The first operational amplifier circuit 201 may include:

[0068] The first operational amplifier N2B, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, the eighth resistor R8, the first potentiometer RP1, and the second capacitor C2;

[0069] One end of the fourth resistor R4 is connected to the output terminal of the third operational amplifier N2A, and the other end is connected to the non-inverting input terminal of the first operational amplifier N2B;

[0070] One end of the fifth resistor R5 is connected to the non-inverting input of the first operational amplifier N2B, and the other end is grounded;

[0071] The sixth resistor R6, the eighth resistor R8, and one end of the second capacitor C2 are connected to the inverting input of the first operational amplifier N2B, and the other end of the eighth resistor R8 and the other end of the second capacitor C2 are connected to the output of the first operational amplifier N2B.

[0072] The other end of the sixth resistor R6 is connected to one end of the seventh resistor R7 and one end of the first potentiometer RP1 and the middle end. The other end of the seventh resistor R7 is grounded. The other end of the first potentiometer RP1 is connected to a preset power signal for providing the voltage signal corresponding to the preset voltage threshold. The voltage value provided by the power signal is 12V.

[0073] Band selection circuit 202 may include:

[0074] Numerical control analog switch integrated circuit, at least two potentiometers;

[0075] The numerical control signal input terminal of the numerical control analog switch integrated circuit is connected to the band selection control signal, one end of the switch is connected to one end of each of at least two potentiometers, and the other end of the switch is the output terminal;

[0076] The middle terminal of each of the at least two potentiometers is grounded to the other terminal.

[0077] The second operational amplifier circuit 203 may include: a second operational amplifier N2C, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, and a third capacitor C3;

[0078] One end of the tenth resistor R10 and the eleventh resistor R11 is connected to the output of the first operational amplifier N2B, and the other end of the tenth resistor R10 is grounded.

[0079] The other end of the eleventh resistor R11, one end of the twelfth resistor R12, and one end of the third capacitor C3 are connected to the inverting input of the second operational amplifier N2C;

[0080] One end of the ninth resistor R9 is connected to a preset power signal, and the other end is connected to the non-inverting input of the second operational amplifier N2C.

[0081] The non-inverting input of the second operational amplifier N2C is connected to the other end of the on / off switch of the digital control analog switch integrated circuit.

[0082] In this invention, exemplarily, it is assumed that the output power of the desired broadband power amplifier is stabilized at P. w For example, 200W, at this time the power detector detects the power detection voltage signal V. P1 =0.2V, the voltage V3 at pin 3 of the third operational amplifier N2A is equal to V. P1 The voltage V1 at pin 1 of the third operational amplifier N2A is:

[0083]

[0084] The voltage V5 at pin 5 of the first operational amplifier N2B is:

[0085]

[0086] The voltage V6 at pin 6 of the first operational amplifier N2B is the voltage threshold V6 used for amplitude stabilization.

[0087]

[0088] Where R2 is the resistance value of resistor R2, R3 is the resistance value of resistor R3, R4 is the resistance value of resistor R4, and R5 is the resistance value of resistor R5.

[0089] In practical applications, the voltage V6 can be adjusted by adjusting the value of potentiometer RP1. When the output power P w When there is an increasing trend, the voltage V P1 This will also increase, causing voltages V1 and V5 to increase. When voltage V5 is greater than voltage V6, the voltage V7 at pin 7 of the first operational amplifier N2B will no longer be 0, resulting in:

[0090] V7 = β B ×(V5-V6),

[0091] Where, β B As the gain of the first operational amplifier N2B increases, the increase in voltage V7 will cause the voltage V at the output of the second operational amplifier N2C to increase. P2 If the voltage drops, the electronically controlled attenuator will attenuate more, preventing P from falling. w The increase of ...

[0092] In this embodiment, for example, the radio frequency signal frequency used by the broadband power amplifier is divided into four bands. For instance, the 100MHz to 500MHz band is divided into four bands: the first band 100MHz to 200MHz, the second band 200MHz to 300MHz, the third band 300MHz to 400MHz, and the fourth band 400MHz to 500MHz. For each sub-band, a corresponding band selection control signal is set. For example, the band selection control signal for the 100MHz to 200MHz band is set to 00, the band selection control signal for the 200MHz to 300MHz band is set to 01, the band selection control signal for the 300MHz to 400MHz band is set to 10, and the band selection control signal for the 400MHz to 500MHz band is set to 11.

[0093] See Figure 5 , Figure 5 In the CNC analog switch integrated circuit, pins A and B are used to connect band selection control signals B0 and B1. By programming the values ​​of B0 and B1, the connection between one end of the switch and the other end can be controlled. One end of the switch is set to 0X corresponding to 00, 1X to 01, 2X to 10, and 3X to 11. When the band selection control signals B0 and B1 correspond to an input of 10, the X and 2X pins of the other end of the switch are connected, and the segmented preset voltage signal corresponding to pin 2X is output. In practical applications, for convenience, the band selection signal controlling an existing segmented filter can be used as the band selection control signal in this invention. However, the same signal has different functions. In this invention, the band selection control signal is used to select the corresponding segmented preset voltage signal for radio frequency signals of different frequency bands.

[0094] Figure 5 For example, four potentiometers are set: potentiometer RP2, potentiometer RP3, potentiometer RP4, and potentiometer RP5. By adjusting the resistance value of each potentiometer, different voltage values ​​corresponding to segmented preset voltage signals are obtained. When the digital control analog switch integrated circuit selects 0X and connects to pin X, the fourth band can be set; when 1X is connected to pin X, the third band is set; when 2X is connected to pin X, the second band is set; and when 3X is connected to pin X, the first band is set. Furthermore, based on the characteristic that the gain of a broadband power amplifier decreases with increasing frequency, the voltage value of the segmented preset voltage signal corresponding to the 100MHz to 200MHz band can be set to be relatively large, while the voltage value of the segmented preset voltage signal corresponding to the 400MHz to 500MHz band can be set to be relatively small. Thus, different attenuation values ​​are used for attenuation processing of radio frequency signals in different frequency bands.

[0095] For example, suppose the power amplifier has a maximum gain of 1000 times in the fourth band. When the input signal is 1W, without processing, the RF amplifier circuit will output 1000W, which will damage or even burn out the power amplifier itself and the downstream circuitry. Therefore, an electrically adjustable attenuator can be used for pre-attenuation to reduce the problem of excessive output power at the start of operation. Assuming that the output signal is not expected to exceed 300W, the electrically adjustable attenuator needs to attenuate by 3.3 times. The voltage value V corresponding to the attenuation value of the input electrically adjustable attenuator controls the voltage value of the voltage signal. P2 For V 3.3倍 Then V P2 =β C ×(V 10 -V9), where β C The gain of the second operational amplifier N2C is given by the voltage V. 10 The voltage value at pin 10 of the second operational amplifier N2C is V9, and the voltage value at pin 9 of the second operational amplifier N2C is V9. At the initial instant, voltage V9 = 0, so V P2 =β C ×V 10 ,Right now Figure 5 In the circuit shown: Then the resistance value R of resistor RP2 P2 for:

[0096]

[0097] Where R9 is the resistance value of resistor R9, V 3.3倍 Determined by the inherent characteristics of the electrically adjustable attenuator, the attenuation value can be obtained from the correspondence between the attenuation value of the actual electrically adjustable attenuator and the voltage value corresponding to the attenuation control voltage signal.

[0098] Similarly, assuming the maximum gain of a broadband power amplifier in the third band is 1500 times, when the input signal is 1W, without processing, the RF amplifier circuit will output 1500W, which will damage or even burn out the power amplifier itself and the downstream circuitry. Therefore, an electrically adjustable attenuator can be used for pre-attenuation to reduce the problem of excessive output power at the start of operation. Assuming the desired output signal is no more than 300W, the electrically adjustable attenuator needs to attenuate by a factor of 5. The corresponding voltage value V of the input electrically adjustable attenuator controls the voltage signal. P2 For V 5倍 Calculate the resistance R of RP3. P3 for:

[0099]

[0100] Among them, V 5倍Determined by the inherent characteristics of the electrically adjustable attenuator, the attenuation value can be obtained from the correspondence between the attenuation value of the actual electrically adjustable attenuator and the voltage value corresponding to the attenuation control voltage signal.

[0101] Similarly, if the maximum gain of a broadband power amplifier in the second band is 1800 times, and the input signal is 1W, without processing, the RF amplifier circuit will output 1800W, which will damage or even burn out the power amplifier itself and the downstream circuitry. Therefore, an electrically adjustable attenuator can be used for pre-attenuation to reduce the problem of excessive output power at the start of operation. Assuming that the output signal is not expected to exceed 300W, the electrically adjustable attenuator needs to attenuate by 6 times, corresponding to the voltage value V of the voltage signal controlled by the attenuation value of the input electrically adjustable attenuator. P2 For V 6倍 Calculate the resistance R of RP4. P4 for:

[0102]

[0103] Among them, V 6倍 Determined by the inherent characteristics of the electrically adjustable attenuator, the attenuation value can be obtained from the correspondence between the attenuation value of the actual electrically adjustable attenuator and the voltage value corresponding to the attenuation control voltage signal.

[0104] Similarly, if a broadband power amplifier has a maximum gain of 2000 times in the first band, and the input signal is 1W, without processing, the RF amplifier circuit will output 2000W, which will damage or even burn out the power amplifier itself and the downstream circuitry. Therefore, an electrically adjustable attenuator can be used for pre-attenuation to reduce the problem of excessive output power at the start of operation. Assuming that the output signal is not expected to exceed 300W, the electrically adjustable attenuator needs to attenuate by 6.6 times. The corresponding voltage value V of the input voltage adjustable attenuator controls the voltage signal. P2 For V 6.6倍 Calculate the resistance R of RP5. P5 for:

[0105]

[0106] Among them, V 6.6倍 Determined by the inherent characteristics of the electrically adjustable attenuator, the attenuation value can be obtained from the correspondence between the attenuation value of the actual electrically adjustable attenuator and the voltage value corresponding to the attenuation control voltage signal.

[0107] In the above embodiments, the first operational amplifier N2B, the second operational amplifier N2C, and the third operational amplifier N2A are operational amplifiers on a single quad operational amplifier integrated circuit LM124. Therefore, Figure 4The illustration only shows an example of powering on the third operational amplifier N2A; in practical applications, the first, second, and third operational amplifiers can be three single-channel operational amplifier integrated circuits; or, two dual-channel operational amplifier integrated circuits can be used. The numerically controlled analog switch integrated circuit is a differential four-channel analog switch integrated circuit CD4052.

[0108] In summary, the technical solution provided by the embodiments of the present invention controls the input power of the input broadband power amplifier, thereby controlling the output power of its output signal. This mainly involves controlling the input power of the input broadband power amplifier and thus controlling the output power of its output signal. When the output signal of the broadband power amplifier is small, its related voltage signal is also small. If it does not exceed the preset voltage threshold, it indicates that the output signal amplitude has not overshooted. Once the output signal of the broadband power amplifier is large and the corresponding related voltage signal exceeds the preset voltage threshold, the first operational amplifier circuit is activated to output a voltage signal for amplitude stabilization.

[0109] Furthermore, in the embodiments of the present invention, the frequency bands of the original radio frequency signal are pre-divided into multiple different frequency bands. For each frequency band, a different segmented preset voltage signal is preset. When the band selection circuit receives the preset band selection control signal, it selects the segmented preset voltage signal corresponding to the frequency band where the output signal is located and outputs it. The second operational amplifier circuit is connected to the segmented preset voltage signal and the amplitude stabilization voltage signal. The voltage value corresponding to the segmented preset voltage signal is fixed, while the amplitude stabilization voltage signal changes with the change of the voltage value corresponding to the relevant voltage signal or the output signal, and the change direction is consistent. Therefore, the change direction of the attenuation control voltage signal output by the second operational amplifier circuit is opposite to the change direction of the amplitude stabilization voltage signal. Based on the characteristics of the electrically adjustable attenuator itself, its attenuation value changes in the opposite direction to the change direction of the attenuation control voltage signal. Therefore, the change direction of the obtained attenuation value is consistent with the change direction of the amplitude stabilization voltage signal or the relevant voltage signal. That is, as the voltage amplitude of the output signal increases, the attenuation value of the electrically adjustable attenuator also increases. Correspondingly, the voltage amplitude of the input signal of the broadband power amplifier decreases, thereby effectively controlling the voltage amplitude of the output signal of the broadband power amplifier to not be too large.

[0110] Furthermore, in the specific implementation, since the segmented preset voltage signals are set for different frequency bands of the output signal, the same attenuation value is not used for attenuation. Instead, for higher frequency band signals, since the corresponding gain is lower, a relatively smaller attenuation value is used for attenuation; for lower frequency band signals, since the corresponding gain is higher, a relatively larger attenuation value is used for attenuation. This effectively controls the amplitude variation of the input signal of the broadband power amplifier to prevent it from becoming too large and keeps it basically stable near its normal output power.

[0111] Those skilled in the art will understand that all or part of the processes of the methods described in the above embodiments can be implemented by a computer program instructing related hardware, and the program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a disk, optical disk, read-only memory, or random access memory, etc.

[0112] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A broadband power amplifier input control circuit, characterized in that, include: The first operational amplifier circuit has a non-inverting input terminal connected to a related voltage signal of the output signal of the broadband power amplifier, an inverting input terminal connected to a voltage signal corresponding to a preset amplitude stabilization voltage threshold, and an output terminal that outputs an amplitude stabilization voltage signal whose changing direction is consistent with the changing direction of the related voltage signal when the output signal increases to the point that the voltage value of the related voltage signal is greater than the preset amplitude stabilization voltage threshold. The band selection circuit has a preset band selection control signal input, selects and outputs a segmented preset voltage signal corresponding to the frequency band of the output signal. The second operational amplifier circuit has the segmented preset voltage signal connected to its non-inverting input terminal and the amplitude stabilization voltage signal connected to its inverting input terminal, and outputs an attenuation control voltage signal whose changing direction is opposite to that of the amplitude stabilization voltage signal. An electrically adjustable attenuator is connected to the attenuation control voltage signal at its input terminal, and outputs a working radio frequency signal obtained by attenuating the original radio frequency signal with an attenuation value whose change direction is consistent with the change direction of the relevant voltage signal, and sends the signal to the broadband power amplifier.

2. The broadband power amplifier input control circuit according to claim 1, characterized in that, The non-inverting input of the first operational amplifier circuit is connected to one output of a power detector, which detects and outputs the relevant voltage signal.

3. The broadband power amplifier input control circuit according to claim 1, characterized in that, The circuit further includes a third operational amplifier circuit; the non-inverting input of the first operational amplifier circuit is connected to an output of the power detector through the third operational amplifier circuit; including: The non-inverting input of the third operational amplifier circuit is connected to one output of the power detector, and the output is connected to the non-inverting input of the first operational amplifier circuit. The non-inverting input terminal of the first operational amplifier circuit is connected to the output terminal of the third operational amplifier circuit.

4. The broadband power amplifier input control circuit according to claim 3, characterized in that, The third operational amplifier circuit includes: The third operational amplifier, the first resistor, the second resistor, the third resistor, and the first capacitor; The non-inverting input of the third operational amplifier is connected to one output of the power detector and one end of the first resistor, and the other end of the first resistor is grounded. The inverting input terminal of the third operational amplifier is connected to one end of the second resistor, one end of the third resistor, and one end of the first capacitor; The other end of the second resistor and the other end of the first capacitor are both connected to the output terminal of the third operational amplifier, and the other end of the third resistor is grounded.

5. The broadband power amplifier input control circuit according to claim 4, characterized in that, The first operational amplifier circuit includes: First operational amplifier, fourth resistor, fifth resistor, sixth resistor, seventh resistor, eighth resistor, first potentiometer, and second capacitor; One end of the fourth resistor is connected to the output terminal of the third operational amplifier, and the other end is connected to the non-inverting input terminal of the first operational amplifier; One end of the fifth resistor is connected to the non-inverting input of the first operational amplifier, and the other end is grounded; One end of the sixth resistor, the eighth resistor, and the second capacitor is connected to the inverting input terminal of the first operational amplifier, and the other end of the eighth resistor and the other end of the second capacitor are connected to the output terminal of the first operational amplifier. The other end of the sixth resistor is connected to one end of the seventh resistor and one end of the first potentiometer and the middle terminal. The other end of the seventh resistor is grounded, and the other end of the first potentiometer is connected to a preset power supply signal for providing the voltage signal corresponding to the preset amplitude stabilization voltage threshold.

6. The broadband power amplifier input control circuit according to claim 5, characterized in that, The band selection circuit includes: Numerical control analog switch integrated circuit, at least two potentiometers; The numerical control signal input terminal of the numerical control analog switch integrated circuit is connected to the band selection control signal, one end of the switch of the numerical control analog switch integrated circuit is connected to one end of each of at least two potentiometers, and the other end of the switch of the numerical control analog switch integrated circuit is the output terminal. The middle terminal of each of the at least two potentiometers is grounded to the other terminal.

7. The broadband power amplifier input control circuit according to claim 6, characterized in that, The second operational amplifier circuit includes: a second operational amplifier, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, and a third capacitor; One end of the tenth resistor and the eleventh resistor are connected to the output terminal of the first operational amplifier, and the other end of the tenth resistor is grounded; The other end of the eleventh resistor, one end of the twelfth resistor, and one end of the third capacitor are connected to the inverting input of the second operational amplifier; One end of the ninth resistor is connected to a power supply, and the other end is connected to the non-inverting input terminal of the second operational amplifier; The non-inverting input of the second operational amplifier is connected to the other end of the on / off switch of the digitally controlled analog switch integrated circuit.

8. The broadband power amplifier input control circuit according to claim 7, characterized in that, The first operational amplifier, the second operational amplifier, and the third operational amplifier are three operational amplifiers on a single quad operational amplifier integrated circuit LM124; or, The first operational amplifier, the second operational amplifier, and the third operational amplifier are three single-channel operational amplifier integrated circuits; or, The first operational amplifier, the second operational amplifier, and the third operational amplifier are implemented using two dual-channel operational amplifier integrated circuits.

9. The broadband power amplifier input control circuit according to claim 6, characterized in that, The numerical control analog switch integrated circuit is a differential four-channel analog switch integrated circuit CD4052.

10. The broadband power amplifier input control circuit according to claim 5, characterized in that, The preset power signal voltage value is 12V.

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