Dynamic frequency adaptive automatic gain control system and method

Abstract

The invention discloses a dynamic frequency adaptive automatic gain control system, which belongs to the field of dynamic frequency adjustment and comprises a radio frequency power amplifier, an attenuator, a logarithmic detector, a low-pass filter and a comparison and control signal generation module. The amplified radio frequency signal is input into the attenuator; the attenuator attenuates the signal so that the input radio frequency signal reaches a range suitable for detection of the logarithmic detector after attenuation; the logarithmic detector converts the radio-frequency signal into a direct-current voltage proportional to the signal power; voltage signals of direct-current voltage output by the logarithmic detector are smoothed through a low-pass filter, and rapidly changing components are removed; and the comparison and control signal generation module compares the smoothed voltage with a reference voltage, generates a control signal for adjusting the gain, and adjusts the gain. According to the invention, instant gain adjustment is provided under the condition of rapidly changing signals, and the energy efficiency of the system is improved.

Description

Technical Field

[0001] The present invention relates to the field of dynamic frequency adjustment, and in particular to an automatic gain control system and method for dynamic frequency adaptation. Background Art

[0002] Existing automatic gain control systems are mainly used to maintain the stability of signal strength. Traditional AGC systems usually use discrete components (such as RF amplifiers, logarithmic detectors and comparators) to achieve signal conditioning, but they are insufficient in terms of fast response, dynamic range and power management. Existing systems may not perform well in high-frequency applications and usually require complex component configurations and high power consumption. Summary of the invention

[0003] One of the purposes of the present invention is to provide a dynamic frequency adaptive automatic gain control system to solve the shortcomings of the automatic gain control system in the prior art that the performance in high frequency applications is not ideal and usually requires complex component configuration and high power consumption.

[0004] The present invention is implemented through the following technical scheme: a dynamic frequency adaptive automatic gain control system, including a radio frequency power amplifier, an attenuator, a logarithmic detector, a low-pass filter and a comparison and control signal generation module, wherein the input signal first enters the radio frequency power amplifier, the radio frequency power amplifier amplifies the input radio frequency signal to enhance the signal strength, and inputs the amplified radio frequency signal into the attenuator; the attenuator is connected to the logarithmic detector, and is used to attenuate the signal so that the input radio frequency signal reaches a range suitable for detection by the logarithmic detector after attenuation; the logarithmic detector is connected to the low-pass filter, and is used to convert the radio frequency signal into a direct current voltage proportional to the signal power; the low-pass filter is connected to the comparison and control signal generation module, and the direct current voltage output by the logarithmic detector is smoothed by the low-pass filter to remove the rapidly changing components and make the signal more stable; the comparison and control signal generation module is used to compare the voltage smoothed by the low-pass filter with the reference voltage, generate a control signal for adjusting the gain, and adjust the gain to ensure that the output signal strength is stable within a preset range.

[0005] Furthermore, the automatic gain control system also includes a feedback loop, which is coupled between the attenuator and the comparison and control signal generation module and is used to input the signal output by the comparison and control signal generation module into the attenuator.

[0006] Furthermore, the comparison and control signal generation module includes a comparator and a variable gain amplifier, the comparator is used to compare the smoothed DC voltage output by the low-pass filter with a reference voltage preset in the comparator, and the comparison result will generate a control signal, and the reference voltage is the desired signal strength level; the variable gain amplifier adjusts its gain according to the control signal to optimize the strength of the output signal and ensure that the amplitude of the output signal remains within a stable range; the control signal is input into the variable gain amplifier, and the variable gain amplifier optimizes the strength of the output signal according to the gain of the smoothed DC voltage described in the control signal. When the comparator detects that the smoothed DC voltage is greater than the reference voltage, the gain of the DC voltage is reduced; when the comparator detects that the smoothed DC voltage is less than the reference voltage, the control signal will increase the gain of the DC voltage.

[0007] Furthermore, the attenuator includes at least three attenuation units; the attenuation units are capable of individually switching the connected attenuation levels, each attenuation unit has an insertion loss mode and an attenuation mode, and a delay subunit depending on the attenuation state, one delay subunit is connected to one attenuation unit, and the delay subunit is used to make the corresponding attenuation unit switch between the insertion loss mode and the attenuation mode at different speeds, when the attenuation unit switches from the attenuation mode to the insertion loss mode, the delay subunit introduces a delay to slow down the switching process, and when the attenuation unit switches from the insertion loss mode to the attenuation mode, the delay subunit does not introduce a delay or introduces a tiny delay to speed up the switching process.

[0008] Furthermore, the attenuation unit includes an attenuation network, a first series switch connected between the attenuation network and ground, a second series switch connected in series between the first series switch and ground and in parallel with a resistor, and a shunt switch connected between the input and output of the attenuator unit; the first series switch is closed to provide an attenuation state. When the first series switch is closed, the input signal passes through the attenuator unit and the signal is attenuated, and the attenuation unit is in an attenuation mode; when the first series switch is switched from a closed state to an open state, the second series switch in parallel with the resistor is used to provide a transition state during the switching process, gradually reducing the current and voltage changes in the attenuation network and reducing the amplitude of transient glitches; when the shunt switch is closed, the input signal bypasses the attenuator unit and is directly output, the signal strength remains unchanged, and the attenuation unit is in an insertion loss mode.

[0009] Furthermore, the attenuator unit also includes a control subunit for providing an intermediate control signal to switch the second series switch during the state transition of the attenuator unit. The control subunit is configured to provide a control signal to at least one of the second series switches. When the first series switch is switched at a predetermined timing, the transmission of the control signal of the second series switch is timed, and the state of the second series switch is changed by delaying the time, thereby ensuring that the current and voltage change smoothly during the switching process and optimizing the transient response.

[0010] Furthermore, the delay subunit includes a resistor and capacitor network and a bypass switch, wherein when the attenuation unit switches from the attenuation mode to the insertion loss mode, the resistor and capacitor network provides a switching delay; when the attenuator stage switches from the insertion loss mode to the attenuation mode, the bypass switch is used to bypass the resistor and capacitor network, thereby eliminating the switching delay.

[0011] Furthermore, the delay subunit also includes digital logic operations. When the attenuation unit switches from the attenuation mode to the insertion loss mode, the switching delay is controlled by the digital logic; when the attenuator stage switches from the insertion loss mode to the attenuation mode, the digital logic does not cause a switching delay.

[0012] On the other hand, the present invention provides a dynamic frequency adaptive automatic gain control method, which includes: when the signal enters the RF power amplifier, the amplifier amplifies the input RF signal to enhance the signal strength and ensure that the signal has sufficient strength in the subsequent processing process; the amplified signal is attenuated by an attenuator; the signal strength is adjusted to an input range suitable for the logarithmic detector; the attenuated RF signal enters the logarithmic detector, and the logarithmic detector converts the RF signal into a DC voltage proportional to the signal power, and the logarithmic detector converts the amplitude of the input signal into a voltage in logarithmic form; the generated DC voltage is smoothed by a low-pass filter to remove high-frequency noise and rapidly changing components, so that the output DC voltage is stable and smooth; the smoothed DC voltage is compared with a preset reference voltage in the comparator, and a control signal is generated according to the comparison result. When the smoothed DC voltage is higher than the reference voltage, it indicates that the signal strength is too high, and the gain of the variable gain amplifier is reduced by the control signal; when the smoothed DC voltage is lower than the reference voltage, it indicates that the signal strength is too low, and the gain of the variable gain amplifier is increased by the control signal.

[0013] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0014] 1. The present invention can provide instant gain adjustment under rapidly changing signal conditions, and can support input of a wider range of signal strengths. In addition, low-power components and efficient power management solutions are used in the design to improve the energy efficiency of the system.

[0015] 2. The present invention improves the attenuator and sets a plurality of attenuation units to achieve multi-stage attenuation of the input signal, so that the power measurement circuit can flexibly provide precise attenuation control and dynamically adjust the signal power to facilitate subsequent measurements. At the same time, through the interaction between the first series switch and the second series switch, the second series switch provides a transition state for the first series switch during the switching process, gradually reducing the current and voltage changes in the attenuation network, thereby reducing the amplitude of transient glitches, and by controlling the switching state of the second series switch, the current passing through the attenuation network can be adjusted to control the power change of the attenuator unit, which helps to keep the power of the attenuator unit within a preselected range, prevent power overshoot or undershoot, and further reduce the impact on the circuit.

[0016] 3. The AGC system design of the present invention has strong dynamic frequency adaptability and can work stably in a wide frequency range. At the same time, by integrating a variable gain amplifier and a logarithmic detector, the number and complexity of system components are reduced, and the reliability and compactness of the system are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0018] Figure 1 A system structure diagram provided for exemplary embodiment 1 of the present invention.

[0019] Figure 2 A method flow chart provided for exemplary embodiment 2 of the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0021] Embodiment 1:

[0022] This embodiment discloses a dynamic frequency adaptive automatic gain control system, such as Figure 1 The automatic gain control system comprises a radio frequency power amplifier, an attenuator, a logarithmic detector, a low-pass filter, a comparison and control signal generation module and a feedback loop.

[0023] The input signal first enters the radio frequency power amplifier, which amplifies the input radio frequency signal to enhance the signal strength, and inputs the amplified radio frequency signal into the attenuator.

[0024] The attenuator is connected to the logarithmic detector and is used to attenuate the signal so that the input radio frequency signal reaches a range suitable for detection by the logarithmic detector after attenuation.

[0025] Specifically, the attenuator includes at least three attenuation units, which are used in series, and each attenuation unit has its own first series switch and shunt switch. By controlling the closing and opening of these switches, different attenuation values ​​can be combined. The total attenuation level is determined by the sum of the unit attenuation values ​​of each attenuator unit. For example, if there are three units, and the unit attenuation value of each unit is 1 dB, 2 dB and 4 dB, then through different combinations, these units can provide attenuation levels from 0 dB to 7 dB. Those skilled in the art can flexibly configure the number of attenuation units according to specific circuit design requirements.

[0026] It should be noted that for a single attenuator unit, it has two working modes, attenuation mode and insertion loss mode. Its attenuation state is that when the first series switch is closed, the input signal passes through the attenuator unit and the signal is attenuated. For example, assuming that the unit attenuation value of the single attenuation unit is 1 dB, the input signal strength will be reduced by 1 dB. The insertion state is that when the shunt switch is closed, the input signal bypasses the attenuator unit and is directly output, and the input signal strength remains unchanged.

[0027] The combination of multiple attenuator units can be, now assume that there are four attenuator units configured, and their unit attenuation values ​​are 1 dB, 2 dB, 4 dB and 8 dB respectively. By controlling the switch state of each unit, any attenuation value between 0 dB and 15 dB can be achieved. For example, to achieve 3 dB attenuation, close the first series switch of the 1 dB and 2 dB units (total attenuation value = 1 dB + 2 dB). To achieve 7 dB attenuation, close the first series switch of the 1 dB, 2 dB and 4 dB units (total attenuation value = 1 dB + 2 dB + 4 dB). To achieve 15 dB attenuation, close the first series switch of all units (total attenuation value = 1 dB + 2 dB + 4 dB + 8 dB).

[0028] That is, each attenuator unit can provide different attenuation states and insertion states through the control of the switch. By combining multiple such units, multi-level attenuation within a range can be achieved.

[0029] So from the above content, it can be seen that the attenuation unit is able to individually switch the connected attenuation level, each attenuation unit has an insertion loss mode and an attenuation mode, and a delay subunit depending on the attenuation state, a delay subunit is connected to an attenuation unit, and the delay subunit is used to make the corresponding attenuation unit switch between the insertion loss mode and the attenuation mode at different speeds. When the attenuation unit switches from the attenuation mode to the insertion loss mode, the delay subunit introduces a delay to slow down the switching process. When the attenuation unit switches from the insertion loss mode to the attenuation mode, the delay subunit does not introduce a delay or introduces a tiny delay to speed up the switching process.

[0030] Specifically, when the attenuator stage switches from attenuation mode to insertion loss mode, transient interference can be reduced by introducing a delay. Rapid switching may cause instantaneous voltage or current changes in the circuit, resulting in signal distortion or noise. Delayed switching can smooth these changes and ensure a stable signal.

[0031] In the present invention, the delay subunit can realize delay by using two methods: analog circuit control and digital logic circuit control.

[0032] In analog circuit control, the delay subunit includes a resistor-capacitor network and a bypass switch, wherein when the attenuation unit switches from an attenuation mode to an insertion loss mode, a switching delay is provided by the resistor-capacitor network; when the attenuator stage switches from an insertion loss mode to an attenuation mode, the bypass switch is used to bypass the resistor-capacitor network, thereby eliminating the switching delay.

[0033] The logarithmic detector is connected to the low-pass filter to convert the RF signal into a DC voltage proportional to the signal power. Specifically, the advantage of the logarithmic detector is that it can handle a wide range of input signal strengths and output a linearly proportional voltage.

[0034] It should be noted that the logarithmic detector can handle a very wide range of input signal strengths and convert it into a DC voltage proportional to the signal power. Due to the characteristics of the logarithmic function, the output voltage can remain within a relatively small range even if the input signal strength varies by several orders of magnitude. This allows the system to handle signals ranging from very weak to very strong without saturation or loss of linearity.

[0035] The low-pass filter is connected to the comparison and control signal generation module. The DC voltage output by the logarithmic detector is smoothed by the low-pass filter to remove the rapidly changing components and make the signal more stable.

[0036] It should be noted that the low-pass filter is used to remove the fast-changing components in the DC voltage output by the logarithmic detector, namely high-frequency noise and transient changes. By smoothing the voltage signal, a more stable DC voltage is obtained. The smoothed signal is more stable, reducing the misadjustment caused by noise or transient signal changes, and improving the stability and reliability of the system.

[0037] The comparison and control signal generation module is used to compare the voltage smoothed by the low-pass filter with the reference voltage, generate a control signal for adjusting the gain, and adjust the gain to ensure that the output signal strength is stable within a preset range.

[0038] It should be noted that the module compares the smoothed voltage with the reference voltage to generate an error signal. The error signal is used to adjust the gain to ensure that the output signal strength is stable within the preset range. Through precise control algorithms, precise adjustment of the gain can be achieved. This improves the accuracy of the system and keeps the output signal strength at a stable level, unaffected by input signal fluctuations.

[0039] Specifically, the comparison and control signal generation module includes a comparator and a variable gain amplifier.

[0040] The comparator is used to compare the smoothed DC voltage output by the low-pass filter with a reference voltage preset in the comparator, and the comparison result will generate a control signal, and the reference voltage is the expected signal strength level.

[0041] The variable gain amplifier adjusts its gain according to the control signal to optimize the strength of the output signal and ensure that the amplitude of the output signal remains within a stable range;

[0042] The control signal is input into the variable gain amplifier, and the variable gain amplifier optimizes the strength of the output signal according to the gain of the smoothed DC voltage of the control signal.

[0043] Specifically, the smoothed DC voltage is compared with a reference voltage preset in the comparator, and a control signal is generated according to the comparison result. When the smoothed DC voltage is higher than the reference voltage, it indicates that the signal strength is too high, and the gain of the variable gain amplifier is reduced through the control signal; when the smoothed DC voltage is lower than the reference voltage, it indicates that the signal strength is too low, and the gain of the variable gain amplifier is increased through the control signal.

[0044] It should be noted that the nonlinear distortion and noise caused by changes in input signal strength can be effectively suppressed by dynamically adjusting the gain, thereby improving the quality of the output signal, reducing distortion and noise, and enabling the system to provide high-quality output under various signal conditions.

[0045] The feedback loop is coupled between the attenuator and the comparison and control signal generation module, and is used to input the signal output by the comparison and control signal generation module into the attenuator.

[0046] It should be noted that the feedback loop inputs the signal output by the comparison and control signal generation module into the attenuator or VGA to form a closed-loop system. This feedback mechanism enables the system to respond to changes in the input signal in real time and make dynamic adjustments. It enhances the response speed and flexibility of the system, enabling it to quickly adapt to changes in the input signal and maintain the stability of the output signal.

[0047] Embodiment 2,

[0048] In this embodiment, a dynamic frequency adaptive automatic gain control method is provided. Figure 2 As shown, the method comprises the following steps:

[0049] Step 1: When the signal enters the RF power amplifier, the amplifier amplifies the input RF signal and enhances the signal strength to ensure that the signal has sufficient strength in the subsequent processing process.

[0050] Step 2: The amplified signal is attenuated by an attenuator to adjust the signal strength to a suitable input range for the logarithmic detector;

[0051] Step 3: The attenuated RF signal enters the logarithmic detector, which converts the RF signal to a DC voltage proportional to the signal power. The logarithmic detector also converts the input signal amplitude to a voltage in logarithmic form; this helps deal with situations where the signal strength varies widely.

[0052] Step 4: The generated DC voltage is smoothed by a low-pass filter to remove high-frequency noise and rapidly changing components, making the output DC voltage stable and smooth.

[0053] Step 5: The smoothed DC voltage is compared with a preset reference voltage in the comparator, and a control signal is generated according to the comparison result. When the smoothed DC voltage is higher than the reference voltage, it indicates that the signal strength is too high, and the gain of the variable gain amplifier is reduced through the control signal; when the smoothed DC voltage is lower than the reference voltage, it indicates that the signal strength is too low, and the gain of the variable gain amplifier is increased through the control signal.

[0054] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A dynamic frequency adaptive automatic gain control system, characterized in that: The automatic gain control system comprises: RF power amplifier, attenuator, logarithmic detector, low-pass filter and comparison and control signal generation module, The input signal first enters the RF power amplifier, which amplifies the input RF signal to enhance the signal strength and inputs the amplified RF signal into the attenuator; The attenuator is connected to the logarithmic detector and is used to attenuate the signal so that the input radio frequency signal reaches a range suitable for detection by the logarithmic detector after attenuation; The logarithmic detector is connected to the low-pass filter to convert the radio frequency signal into a DC voltage proportional to the signal power; The low-pass filter is connected to the comparison and control signal generation module, and the DC voltage output by the logarithmic detector is smoothed by the low-pass filter to remove the rapidly changing components and make the signal more stable; The comparison and control signal generation module is used to compare the voltage smoothed by the low-pass filter with the reference voltage, generate a control signal for adjusting the gain, and adjust the gain to ensure that the output signal strength is stable within a preset range.

2. The dynamic frequency adaptive automatic gain control system according to claim 1, characterized in that: The automatic gain control system further comprises a feedback loop, which is coupled between the attenuator and the comparison and control signal generation module and is used to input the signal output by the comparison and control signal generation module into the attenuator.

3. The dynamic frequency adaptive automatic gain control system according to claim 1, characterized in that: The comparison and control signal generation module includes a comparator and a variable gain amplifier. The comparator is used to compare the smoothed DC voltage output by the low-pass filter with a reference voltage preset in the comparator, and the comparison result will generate a control signal, and the reference voltage is the desired signal strength level; The variable gain amplifier adjusts its gain according to the control signal to optimize the strength of the output signal and ensure that the amplitude of the output signal remains within a stable range; The control signal is input into a variable gain amplifier, and the variable gain amplifier adjusts the gain of the smoothed DC voltage according to the control signal to optimize the strength of the output signal. When the comparator detects that the smoothed DC voltage is greater than the reference voltage, the gain of the DC voltage is reduced; When the comparator detects that the smoothed DC voltage is less than the reference voltage, the control signal increases the gain of the DC voltage.

4. The dynamic frequency adaptive automatic gain control system according to claim 1, characterized in that: The attenuator comprises at least three attenuation units; The attenuation units are capable of switching connected attenuation levels individually, each attenuation unit having an insertion loss mode and an attenuation mode, and a delay subunit depending on the attenuation state, one delay subunit being connected to one attenuation unit, The delay subunit is used for the corresponding attenuation unit to switch between insertion loss mode and attenuation mode at different speeds. When the attenuation unit switches from attenuation mode to insertion loss mode, the delay subunit introduces a delay to slow down the switching process. When the attenuation unit switches from the insertion loss mode to the attenuation mode, the delay subunit introduces no delay or introduces a tiny delay to make the switching process faster.

5. The power measurement circuit according to claim 4, characterized in that: The attenuation unit comprises: an attenuation network, and a first series switch connected between the attenuation network and ground, and a second series switch connected in series between the first series switch and ground and in parallel with the resistor, and a shunt switch connected between the input and output of the attenuator unit; The first series switch is closed to provide an attenuation state. When the first series switch is closed, the input signal passes through the attenuator unit, the signal is attenuated, and the attenuation unit is in an attenuation mode; When the first series switch switches from a closed state to an open state, the second series switch connected in parallel with the resistor is used to provide a transition state during the switching process, gradually reducing the current and voltage changes in the attenuation network and reducing the amplitude of the transient burr; When the shunt switch is closed, the input signal bypasses the attenuator unit and is directly output, the signal strength remains unchanged, and the attenuation unit is in insertion loss mode.

6. The power measurement circuit according to claim 5, characterized in that: The attenuator unit further includes a control subunit for providing an intermediate control signal to switch the second series switch during the state transition of the attenuator unit. The control subunit is configured to provide a control signal to at least one of the second series switches. When the first series switch is switched in a predetermined timing, the transmission of the control signal of the second series switch is timed, and the state of the second series switch is changed by delaying the time, thereby ensuring that the current and voltage change smoothly during the switching process and optimizing the transient response.

7. The power measurement circuit according to claim 4, characterized in that: The delay subunit includes a resistor-capacitor network and a bypass switch, wherein: The resistor-capacitor network provides a switching delay when the attenuation unit switches from attenuation mode to insertion loss mode; When the attenuator stage switches from the insertion loss mode to the attenuation mode, the bypass switch is used to bypass the resistor-capacitor network, thereby eliminating the switching delay.

8. The power measurement circuit according to claim 4, characterized in that: The delay subunit also includes digital logic operations, When the attenuation unit switches from the attenuation mode to the insertion loss mode, the switching delay is controlled by digital logic; When the attenuator stage switches from insertion loss mode to attenuation mode, the digital logic causes no switching delay.

9. A dynamic frequency adaptive automatic gain control method, characterized in that: The automatic gain control method comprises: When the signal enters the RF power amplifier, the amplifier amplifies the input RF signal and enhances the signal strength to ensure that the signal has sufficient strength in the subsequent processing process; The amplified signal is attenuated by the attenuator to adjust the signal strength to a suitable input range for the logarithmic detector; The attenuated RF signal enters the logarithmic detector, which converts the RF signal into a DC voltage proportional to the signal power. At the same time, the logarithmic detector converts the amplitude of the input signal into a voltage in logarithmic form; The generated DC voltage is smoothed by a low-pass filter to remove high-frequency noise and rapidly changing components, making the output DC voltage stable and smooth; The smoothed DC voltage is compared with the reference voltage preset in the comparator, and a control signal is generated based on the comparison result. When the smoothed DC voltage is higher than the reference voltage, it indicates that the signal strength is too high, and the gain of the variable gain amplifier is reduced through the control signal; when the smoothed DC voltage is lower than the reference voltage, it indicates that the signal strength is too low, and the gain of the variable gain amplifier is increased through the control signal.

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