Receiving radio frequency front end and broadband temperature compensation amplitude stabilization method thereof
By designing the frequency conversion, mixing, and AGC units of the receiving RF front-end, and combining temperature and frequency compensation algorithms, the problem of signal amplitude instability under wide bandwidth and large temperature difference environments was solved, achieving stable output of RF signals and improving the detection sensitivity and measurement accuracy of the system.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-01
- Publication Date
- 2026-04-14
AI Technical Summary
In wide-bandwidth and extreme temperature environments, the amplitude of the received radio frequency signal is unstable, which leads to a decrease in the system's detection sensitivity and measurement accuracy. Existing AGC designs cannot meet the demodulator's operating requirements.
The design employs a receiving RF front-end, including a frequency conversion unit, a local oscillator unit, an AGC unit, and a control unit. Through internal control and algorithm adjustment, it achieves controllable signal attenuation and dynamic voltage feedback adjustment, resulting in a stable output signal amplitude.
In wide-bandwidth and large-temperature-difference environments, the power stability of the radio frequency signal is achieved, with an output power error of less than 0.1dB, ensuring signal quality.
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Figure CN121864115A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of wireless communication technology, and more specifically, to a receiving radio frequency front end and its wideband temperature-compensated amplitude stabilization method. Background Technology
[0002] In wireless communication receivers, the received signal strength can vary by millions of times due to distance, obstruction, and signal fading. AGC (Automatic Gain Control) adjusts the gain of the intermediate frequency amplifier in real time, compressing this extremely dynamic input signal into a constant amplitude output. This ensures that the subsequent demodulator can function properly, preventing weak signals from being overwhelmed by noise or strong signals from causing saturation distortion, thus guaranteeing the quality of calls and data transmission.
[0003] However, when the receiving front-end needs to cover a wide frequency range from ultra-shortwave to millimeter wave, and simultaneously maintain signal amplitude stability in extreme temperature environments ranging from -40℃ to 85℃, conventional closed-loop AGC designs cannot meet the operational requirements of the subsequent demodulator. This requirement stems from the dual characteristics of RF device parameters drifting with frequency and changing with temperature in wideband scenarios, and this issue has become a key bottleneck restricting the system's detection sensitivity and measurement accuracy.
[0004] Therefore, there is an urgent need for a radio frequency receiving solution that can achieve stable power output under large temperature differences and wide bandwidth. Summary of the Invention
[0005] In view of the above problems, the purpose of this invention is to provide a receiving radio frequency front end and its wideband temperature-compensated amplitude stabilization method, which solves the stability problem of radio frequency signal transmission in wide-band environments with large temperature differences through internal control and algorithm adjustment.
[0006] On one hand, the present invention provides a receiving radio frequency front end, including a frequency conversion unit, a local oscillator unit, an AGC unit, and a control unit, wherein, The frequency conversion unit is used to perform gain, filtering and mixing processing on the received wide-bandwidth radio frequency signal to output the target intermediate frequency signal; The local oscillator unit is used to provide a local oscillator signal for the mixing process of the frequency converter unit based on the local oscillator reference signal provided by the control unit. The AGC unit is used to controllably attenuate the target intermediate frequency signal output by the frequency converter unit, and to perform voltage feedback dynamic adjustment processing on the controllably attenuated signal according to the reference voltage provided by the control unit, so as to output a stable control signal. The control unit is used to provide a local oscillator reference signal to the local oscillator unit based on ambient temperature and preset control information, and to provide a reference voltage for dynamic voltage feedback adjustment to the AGC unit.
[0007] Alternatively, the frequency converter unit may include a first amplifier, a first filter, a mixer, a second filter, and a second amplifier connected in series; wherein, The first amplifier and the second amplifier are used to provide signal gain for the frequency conversion unit; The first filter is used to suppress out-of-band spurious signals and image frequencies in the radio frequency signal amplified by the first amplifier; The mixer is used to perform frequency mixing processing on the radio frequency signal output by the first filter according to the local oscillator signal provided by the local oscillator unit, so as to obtain an intermediate frequency signal. The second filter is used to suppress out-of-band spurious signals and local oscillator leakage in the intermediate frequency signal.
[0008] Alternatively, the AGC unit may include a controllable attenuation circuit and a voltage feedback circuit; wherein, The controllable attenuation circuit includes a first analog attenuator, a third amplifier, a second analog attenuator, and a coupler connected in series; wherein, the first analog attenuator and the second analog attenuator are used to controllably attenuate the target intermediate frequency signal, and the coupler is used to extract the intermediate frequency signal output by the second analog attenuator; The voltage feedback circuit includes a detector and a first operational amplifier; wherein the detector is used to detect a DC voltage that varies with the output signal power based on the intermediate frequency signal output by the second analog attenuator; the first operational amplifier is used to compare the DC voltage with a reference voltage output by the control unit to obtain an attenuation indication voltage that controls the attenuation values of the first analog attenuator and the second analog attenuator.
[0009] On the other hand, the present invention also provides a wideband temperature-compensated amplitude stabilization method for a receiving radio frequency front end, comprising the following steps: S210: Performs gain, filtering, and mixing processing on the received wideband RF signal to output the target intermediate frequency signal; including: Primary gain and filtering are performed on the received wideband radio frequency signals; Based on the local oscillator signal provided by the local oscillator unit, the primary gain and filtered RF signal are mixed to obtain the intermediate frequency signal. The intermediate frequency signal is subjected to two-stage gain and filtering processing to output the target intermediate frequency signal; S220: Perform controllable attenuation and voltage feedback dynamic adjustment processing on the target intermediate frequency signal to output a stable amplitude control signal; including: The target intermediate frequency signal is controllably attenuated using a two-stage analog attenuator to obtain the intermediate frequency signal. The detector detects the DC voltage in the intermediate frequency signal that varies with the output signal power. The DC voltage and the preset reference voltage are processed by an operational amplifier to obtain the attenuation indication voltage that controls the attenuation value of the two-stage analog attenuator. The reference voltage is determined based on the ambient temperature and a preset compensation frequency.
[0010] Alternatively, the mixing process of the primary gain and filtered RF signal based on the local oscillator signal provided by the local oscillator unit includes: Based on the front-loop phase-locked system, the first preset frequency output by the control unit is subjected to front-loop phase-locked processing to obtain the first phase-locked frequency; Based on the phase-locked loop, the first phase-locked frequency is processed by the second preset frequency output by the control unit to obtain the local oscillator signal; The radio frequency signal output from the first filter is mixed according to the local oscillator signal.
[0011] Alternatively, an alternative approach is to determine the reference voltage based on ambient temperature and a preset compensation frequency, including: The reference signal set by the host computer is converted into digital and then into analog signals by two digital-to-analog converters to obtain the first reference voltage and the second reference voltage. The first reference voltage is adjusted according to the ambient temperature to compensate for the output power error caused by temperature changes; and the second reference voltage is adjusted according to a preset compensation frequency to compensate for the output power error caused by frequency changes. The adjusted first reference voltage and the second reference voltage are superimposed to output the reference voltage.
[0012] The above-mentioned receiving radio frequency front-end and its wideband temperature-compensated amplitude stabilization method provided by the present invention are based on the local oscillator signal after specific processing. The received wideband radio frequency signal is converted into an intermediate frequency signal by a frequency conversion unit. Then, the intermediate frequency signal after frequency conversion is controlled to attenuate and dynamically adjusted by voltage feedback by an AGC unit to output a stable control signal, thereby maintaining the stability of output power even in wideband environments with large temperature differences.
[0013] To achieve the foregoing and related objectives, one or more aspects of the invention include the features which will be described in detail below and specifically pointed out in the claims. The following description and accompanying drawings illustrate certain exemplary aspects of the invention. However, these aspects indicate only a few of the various ways in which the principles of the invention can be used. Furthermore, the invention is intended to include all such aspects and their equivalents. Attached Figure Description
[0014] Other objects and results of the invention will become more apparent and readily understood with reference to the following description taken in conjunction with the accompanying drawings and the contents of the claims, and with a more complete understanding of the invention. In the drawings: Figure 1 This is a schematic diagram of the logic circuit of the receiving radio frequency front end according to an embodiment of the present invention; Figure 2 This is a schematic flowchart of a wideband temperature-compensated amplitude stabilization method for a receiving radio frequency front end according to an embodiment of the present invention; Figure 3 This is a process for mixing the primary gain and filtered radio frequency signal based on the local oscillator signal according to an embodiment of the present invention; Figure 4 This describes the process for determining a reference voltage based on ambient temperature and a preset compensation frequency according to an embodiment of the present invention.
[0015] In all the accompanying drawings, the same reference numerals indicate similar or corresponding features or functions. Detailed Implementation
[0016] In the following description, numerous specific details are set forth for illustrative purposes and to provide a thorough understanding of one or more embodiments. However, it will be apparent that these embodiments may also be implemented without these specific details. In other instances, well-known structures and devices are shown in block diagram form for ease of description of one or more embodiments.
[0017] To address the problem of unstable signal amplitude during broadband radio frequency signal transmission under extreme temperature conditions, this invention provides a receiving radio frequency front-end and its broadband temperature-compensated amplitude stabilization method.
[0018] Figure 1 The logic circuit of the receiving radio frequency front end according to an embodiment of the present invention is shown. Figure 2 The flowchart of a wideband temperature-compensated amplitude stabilization method for a receiving radio frequency front-end according to an embodiment of the present invention is shown, consisting of... Figure 1 and Figure 2 As shown in the accompanying drawings, the receiving RF front-end and its wideband temperature-compensated amplitude stabilization method provided by this invention mainly solve the problem of RF signal transmission power stability in environments with wide bandwidth and large temperature differences through internal control algorithms. The method will be described in detail below with reference to the accompanying drawings.
[0019] The receiving RF front-end provided by this invention is a wideband temperature-compensated amplitude-stabilized receiving RF front-end, mainly composed of a frequency conversion unit, a local oscillator unit, an AGC unit, and a control unit. The frequency conversion unit primarily receives the RF signal into the intermediate frequency signal. The local oscillator unit provides the local oscillator signal to the frequency conversion unit. The AGC unit stably outputs the input wide dynamic range signal. The control unit controls the local oscillator unit and the AGC unit. This design architecture can receive power signals from -80dBm to -10dBm and output a stable 0dBm signal.
[0020] Specifically, the frequency conversion unit is used to perform gain, filtering, and mixing processing on the received wide-bandwidth radio frequency signal to output the target intermediate frequency signal, such as... Figure 1 As shown, the frequency conversion unit includes a first amplifier (amplifier 1), a first filter (filter 1), a mixer, a second filter (filter 2), and a second amplifier (filter 2) connected in series. The first and second amplifiers provide signal gain to the frequency conversion unit to ensure link gain. The first filter suppresses out-of-band spurious signals and image frequencies in the amplified RF signal. The mixer mixes the RF signal output from the first filter based on the local oscillator signal provided by the local oscillator unit, intermodulating the local oscillator frequency and the RF frequency to obtain an intermediate frequency (IF) signal. The second filter suppresses out-of-band spurious signals and local oscillator leakage in the mixed IF signal to ensure signal quality. Finally, the signal is amplified by amplifier 2 and output to the AGC unit.
[0021] The AGC unit mainly includes a controllable attenuation circuit and a voltage feedback circuit; among which, such as Figure 1 As shown, the controllable attenuation circuit includes a first analog attenuator (analog attenuator 1), a third amplifier (amplifier 3), a second analog attenuator (analog attenuator 2), and a coupler connected in series. The first and second analog attenuators are used to controllably attenuate the target intermediate frequency signal output by the frequency converter unit. After the target intermediate frequency signal is attenuated by analog attenuator 1, it is amplified by amplifier 3 and then further attenuated by analog attenuator 2 before being output to the coupler. The coupler extracts the intermediate frequency signal output by analog attenuator 2.
[0022] The voltage feedback circuit mainly includes a detector and a first operational amplifier; among which, such as Figure 1As shown, detector 1 detects the DC voltage that varies with the output signal power based on the intermediate frequency signal output by analog attenuator 2, and outputs it to the positive terminal of the first operational amplifier. The first operational amplifier (op-amp 1) integrates and compares the DC voltage with the reference voltage output by the control unit to obtain an attenuation indication voltage that controls the attenuation values of the first and second analog attenuators. Specifically, when the RF signal power increases, the detection voltage increases, the output voltage of op-amp 1 increases, the attenuation of analog attenuators 1 and 2 increases, and the output signal power decreases. When the RF signal power decreases, the detection voltage decreases, the output voltage of op-amp 1 decreases, the attenuation of analog attenuators 1 and 2 decreases, and the output signal power increases. Thus, the output power can be controlled by adjusting the reference voltage. The AGC unit implements a feedback loop through a voltage feedback circuit, enabling dynamic adjustment when the input signal power changes, thus stabilizing the amplitude of the output RF signal. The stable amplitude is determined by the reference voltage, which can be adjusted by the "MCU + digital-to-analog converter" to achieve amplitude regulation.
[0023] The local oscillator unit in this embodiment includes a front-loop phase-locked system and a phase-locked loop. Wherein, as... Figure 1 As shown, the front-loop phase-locked system includes a phase detector and a VCO (voltage-controlled oscillator), used to perform front-loop phase-locking processing on the first preset frequency output by the control unit to obtain the first phase-locked frequency. In a specific embodiment of the present invention, the output frequency generated by the front-loop phase-locked system is 100MHz-210MHz. The phase-locked loop uses the 100MHz-210MHz generated by the front loop as a reference frequency for the rear-loop phase-locking, outputting the local oscillator frequency required by the frequency converter unit. Specifically, as... Figure 1 As shown, the phase-locked loop performs a second-loop phase-locked processing on the first phase-locked frequency according to the second preset frequency output by the control unit, and then the local oscillator signal after the second-loop phase-locked processing is amplified by amplifier 4 and output to the mixer of the frequency converter unit.
[0024] The control unit includes a microcontroller (MCU) and a host computer and a digital-to-analog converter connected to the microcontroller. Specifically, as an example, such as... Figure 1As shown, the host computer sets the frequency and output power of the reference signal for the MCU. The MCU controls each component (analog-to-digital converter 1, analog-to-digital converter 2, phase-locked loop of the local oscillator unit, and phase detector) according to the frequency and power parameters set by the host computer. The reference signal is related to the local oscillator reference signal provided by the microcontroller to the local oscillator unit and the reference voltage provided to the AGC unit. That is, the microcontroller controls the local oscillator unit and the AGC unit according to the reference signal. This reference signal includes a first preset frequency signal output to the local oscillator unit for post-phase-locked processing and a second preset frequency signal output to the local oscillator unit for pre-phase-locked processing, as well as a reference signal output to the digital-to-analog converter.
[0025] Specifically, as an example, the control unit also includes a second operational amplifier, and the digital-to-analog converter includes a first digital-to-analog converter and a second digital-to-analog converter. Figure 1 As shown, the microcontroller inputs the reference signal set by the host computer into the first digital-to-analog converter (DAC1) and the second digital-to-analog converter (DAC2) to obtain the first reference voltage and the second reference voltage. The second operational amplifier (op-amp 2) superimposes the first reference voltage and the second reference voltage to output the reference voltage required by the AGC unit to the first operational amplifier (op-amp 1).
[0026] In other words, the reference voltage is adjusted by superposition. The MCU is connected to analog converter 1 and analog converter 2, which output reference voltage 1 and reference voltage 2. Operational amplifier 2 superimposes reference voltage 1 and reference voltage 2 and outputs it to operational amplifier 1 as the reference voltage.
[0027] In this embodiment, the microcontroller adjusts the first reference voltage and the second reference voltage based on a preset broadband temperature compensation algorithm. The first reference voltage is automatically adjusted according to the ambient temperature, while the second reference voltage is automatically adjusted according to the frequency setting. At different temperatures, the MCU processes the temperature and adjusts the first reference voltage to compensate for output power errors caused by temperature changes, thus solving the problem of stable power output errors. At different frequencies, the MCU adjusts the second reference voltage according to the frequency value to compensate for output power errors caused by frequency variations.
[0028] This AGC circuit can achieve stable output power of the receiving RF front end under different temperatures and frequencies. Experiments have shown that the power error of the output circuit is <0.1dB.
[0029] Therefore, in one embodiment of the present invention, the control unit further includes a temperature sensor connected to the microcontroller for real-time detection of the ambient temperature. The temperature sensor can be implemented using any device capable of real-time ambient temperature detection, and is not particularly limited herein. Furthermore, in the specific implementation of the present invention, the specific circuits implementing the above units are not limited to the circuits given in the above embodiments. The specific circuit configuration can be flexibly determined as needed, such as the number of filters and amplifiers. The specific implementation of each device can be any device capable of achieving the corresponding function, and is not particularly limited herein.
[0030] The above broadband temperature compensation algorithm can be used to calculate the compensation reference voltage using the following formula: ; Where f represents the real-time frequency of the radio frequency signal, f0 represents the center frequency, t represents the real-time ambient temperature of the radio frequency signal, t0 represents the reference temperature, v0 represents the reference voltage at f0 and t0, a1 and a2 represent the first and second order compensation coefficients of the frequency, respectively, b1 and b2 represent the first and second order compensation coefficients of the temperature, respectively, and c represents the cross-coupling coefficient of frequency and temperature.
[0031] The compensation reference voltage is the reference voltage output to the first operational amplifier. The purpose of this formula is to compensate the reference voltage according to changes in frequency and temperature, so that the AGC control can automatically adjust the reference voltage as the frequency and temperature change to maintain the stability of the system gain.
[0032] The function of each term in the formula will be analyzed in detail below: 1. Constant term: 1 The constant term is the baseline term, that is, when f=f0 and t=t0, v_comp = v0.
[0033] 2. Frequency linear term:
[0034] The frequency linearity term represents the linear adjustment of the reference voltage when the frequency deviates from the center frequency f0. a1 is the linearity coefficient, which is usually used to compensate for the linear change of gain with frequency.
[0035] 3. Quadratic term of frequency:
[0036] The frequency quadratic term represents the quadratic compensation for frequency deviation, used to compensate for the nonlinear change of gain with frequency (in broadband systems, the gain may change with frequency in a quadratic curve).
[0037] 4. Temperature linearity term:
[0038] The temperature linearity term represents the linear adjustment of the reference voltage when the temperature deviates from the reference temperature t0. b1 is the temperature linearity coefficient, used to compensate for the linear drift of the gain with temperature.
[0039] 5. Temperature quadratic term:
[0040] The temperature quadratic term represents the quadratic compensation for temperature deviation, used to compensate for the nonlinear drift of gain with temperature (e.g., some devices exhibit nonlinearity at high or low temperatures).
[0041] 6. Intersecting items:
[0042] Cross terms represent the interaction between frequency and temperature. For example, a change in temperature may affect the frequency response, or a change in frequency may affect temperature characteristics. Cross terms can compensate for this coupling effect.
[0043] To determine the coefficients a1, a2, b1, b2, and c, system calibration is typically required. In one specific embodiment of the present invention, the calibration steps include: S110: At a reference temperature t0, scan the frequency f and measure the gain to determine a1 and a2; S120: At the center frequency f0, scan the temperature t and measure the gain to determine b1 and b2; S130: Measure the gain under different combinations of temperature and frequency to determine the cross-coupling coefficient c.
[0044] In AGC control, it is generally desirable to maintain a constant output power. Therefore, v_comp can be used as the reference voltage in the AGC loop. When the frequency of the input RF or the ambient temperature changes, the reference voltage will automatically adjust, thereby changing the start point of the AGC and compensating for the gain changes caused by frequency and temperature variations, thus keeping the output power stable.
[0045] The specific process for wideband temperature-compensated amplitude stabilization of RF signals using the above-mentioned receiving RF front-end is as follows: Figure 2 As shown, firstly, in step S210, the received wideband radio frequency signal undergoes gain, filtering, and mixing processing to output the target intermediate frequency signal; further comprising: S211: Perform primary gain and filtering on the received wideband RF signal; S212: Based on the local oscillator signal provided by the local oscillator unit, the primary gain and filtered RF signal are mixed to obtain the intermediate frequency signal; S213: Perform two-stage gain and filtering processing on the intermediate frequency signal to output the target intermediate frequency signal.
[0046] Comparison Figure 1 It can be seen that this step is mainly implemented by the radio frequency unit.
[0047] Figure 3 The specific flow of step S212 according to an embodiment of the present invention is shown, as follows: Figure 3 As shown, step S212, the step of mixing the primary gain and filtered RF signal based on the local oscillator signal provided by the local oscillator unit, further includes: S2121: Based on the front-loop phase-locked system, the first preset frequency output by the control unit is subjected to front-loop phase-locked processing to obtain the first phase-locked frequency; S2122: Based on the phase-locked loop, the first phase-locked frequency is processed by the second preset frequency output by the control unit to obtain the local oscillator signal; S2123: Perform mixing processing on the primary filtered radio frequency signal according to the local oscillator signal.
[0048] Comparison Figure 1 It can be seen that this step is mainly implemented by the local oscillator unit.
[0049] Then, in step S220, the target intermediate frequency signal is subjected to controllable attenuation and voltage feedback dynamic adjustment processing to output a stable modulation signal, which further includes: S221: The target intermediate frequency signal is controllably attenuated based on a two-stage analog attenuator to obtain the intermediate frequency signal; S222: Detect the DC voltage in the intermediate frequency signal that varies with the output signal power based on the detector; S223: The DC voltage and the preset reference voltage are processed by an operational amplifier to obtain an attenuation indication voltage that controls the attenuation value of the two-stage analog attenuator.
[0050] Comparison Figure 1 It can be seen that this step is mainly implemented by the AGC unit.
[0051] As mentioned above, the reference voltage is determined based on the ambient temperature and a preset compensation frequency, which can be set by inputting from a host computer. Figure 4 The specific flow of step S223 according to an embodiment of the present invention is shown, as follows: Figure 4 As shown, the method for determining the reference voltage based on ambient temperature and a preset compensation frequency in step S223 may include: S2231: The reference signal set by the host computer is converted into digital and then into analog signals by two digital-to-analog converters to obtain the first reference voltage and the second reference voltage. S2232: Adjust the first reference voltage according to the ambient temperature to compensate for the output power error caused by temperature change; and adjust the second reference voltage according to the preset compensation frequency to compensate for the output power error caused by frequency change. S2233: The adjusted first reference voltage and the second reference voltage are superimposed to output the reference voltage.
[0052] More specific implementations of the wideband temperature-compensated amplitude stabilization method for the above-mentioned receiving radio frequency front-end can be found in the foregoing description of the embodiments for the receiving radio frequency front-end, and will not be detailed here.
[0053] The receiving radio frequency front-end and its wideband temperature-compensated amplitude stabilization method according to the present invention have been described above by way of example with reference to the accompanying drawings. In the several embodiments provided by the present invention, it should be understood that the disclosed devices, systems, and methods can also be implemented in other ways. The system embodiments described above are merely illustrative, and the division of units is only a logical functional division; in actual implementation, there may be other division methods. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple circuit modules. Some or all of the units can be selected to implement the scheme of this embodiment according to actual needs.
[0054] Furthermore, the functional circuits in the various embodiments of this invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. Clearly, the word "comprising" does not exclude other units or steps, and the singular does not exclude the plural. Multiple units or circuit devices stated in the system claims can also be implemented by a single unit or circuit.
[0055] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be embraced within the present invention. No appended diagram markings in the claims should be construed as limiting the scope of the claims.
Claims
1. A receiving radio frequency front end, characterized in that, It includes a frequency converter unit, a local oscillator unit, an AGC unit, and a control unit, among which, The frequency conversion unit is used to perform gain, filtering and mixing processing on the received wide-bandwidth radio frequency signal to output the target intermediate frequency signal; The local oscillator unit is used to provide a local oscillator signal for the mixing process of the frequency conversion unit based on the local oscillator reference signal provided by the control unit; The AGC unit is used to controllably attenuate the target intermediate frequency signal output by the frequency converter unit, and to perform voltage feedback dynamic adjustment processing on the controllably attenuated signal according to the reference voltage provided by the control unit, so as to output a stable control signal. The control unit is used to provide a local oscillator reference signal to the local oscillator unit based on ambient temperature and preset control information, and to provide a reference voltage for dynamic voltage feedback adjustment to the AGC unit.
2. The receiving radio frequency front end as described in claim 1, characterized in that, The frequency conversion unit includes a first amplifier, a first filter, a mixer, a second filter, and a second amplifier connected in series; wherein... The first amplifier and the second amplifier are used to provide signal gain for the frequency conversion unit; The first filter is used to suppress out-of-band spurious signals and image frequencies in the radio frequency signal amplified by the first amplifier; The mixer is used to perform frequency mixing processing on the radio frequency signal output by the first filter according to the local oscillator signal provided by the local oscillator unit, so as to obtain an intermediate frequency signal. The second filter is used to suppress out-of-band spurious signals and local oscillator leakage in the intermediate frequency signal.
3. The receiving radio frequency front end as described in claim 1 or 2, characterized in that, The AGC unit includes a controllable attenuation circuit and a voltage feedback circuit; wherein... The controllable attenuation circuit includes a first analog attenuator, a third amplifier, a second analog attenuator, and a coupler connected in series; wherein, the first analog attenuator and the second analog attenuator are used to controllably attenuate the target intermediate frequency signal, and the coupler is used to extract the intermediate frequency signal output by the second analog attenuator; The voltage feedback circuit includes a detector and a first operational amplifier; wherein the detector is used to detect a DC voltage that varies with the output signal power based on the intermediate frequency signal output by the second analog attenuator; the first operational amplifier is used to compare the DC voltage with a reference voltage output by the control unit to obtain an attenuation indication voltage that controls the attenuation values of the first analog attenuator and the second analog attenuator.
4. The receiving radio frequency front end as described in claim 3, characterized in that, The local oscillator unit includes a front-loop phase-locked system and a phase-locked loop; wherein... The front-loop phase-locked system includes a phase detector and a VCO, which are used to perform front-loop phase-locked processing on the first preset frequency output by the control unit to obtain the first phase-locked frequency. The phase-locked loop is used to perform a post-loop phase-locking process on the first phase-locked frequency according to the second preset frequency output by the control unit, so as to output the local oscillator signal required by the local oscillator unit.
5. The receiving radio frequency front end as described in claim 4, characterized in that, The frequency range of the first phase-locked frequency is 100MHz-210MHz.
6. The receiving radio frequency front end as described in claim 4, characterized in that, The control unit includes a microcontroller and a host computer and a digital-to-analog converter respectively connected to the microcontroller; wherein, The host computer is used to set the frequency and output power of the reference signal; wherein, the reference signal is related to the local oscillator reference signal provided by the microcontroller to the local oscillator unit and the reference voltage provided to the AGC unit; The microcontroller is used to control the local oscillator unit and the AGC unit according to the reference signal.
7. The receiving radio frequency front end as described in claim 6, characterized in that, The control unit further includes a second operational amplifier, and the digital-to-analog converter includes a first digital-to-analog converter and a second digital-to-analog converter; wherein... The microcontroller inputs the reference signal set by the host computer into the first digital-to-analog converter and the second digital-to-analog converter respectively to obtain the first reference voltage and the second reference voltage; The second operational amplifier is used to superimpose the first reference voltage and the second reference voltage to output the reference voltage to the first operational amplifier of the AGC unit.
8. The receiving radio frequency front end as described in claim 7, characterized in that, The control unit also includes a temperature sensor connected to the microcontroller for real-time detection of ambient temperature.
9. The receiving radio frequency front end as described in claim 8, characterized in that, The microcontroller is also used to adjust the first reference voltage and the second reference voltage based on a preset broadband temperature compensation algorithm; including: The first reference voltage is adjusted according to the ambient temperature to compensate for the output power error caused by temperature changes; and, The second reference voltage is adjusted according to a preset compensation frequency to compensate for the output power error caused by frequency changes; The broadband temperature compensation algorithm calculates the compensation reference voltage using the following formula: ； Where f represents the real-time frequency of the radio frequency signal, f0 represents the center frequency, t represents the real-time ambient temperature of the radio frequency signal, t0 represents the reference temperature, v0 represents the reference voltage at f0 and t0, a1 and a2 represent the first and second order compensation coefficients of the frequency, respectively, b1 and b2 represent the first and second order compensation coefficients of the temperature, respectively, and c represents the cross-coupling coefficient of frequency and temperature.
10. A broadband temperature-compensated amplitude stabilization method for a receiving radio frequency front-end, characterized in that, Includes the following steps: S210: Performs gain, filtering, and mixing processing on the received wideband RF signal to output the target intermediate frequency signal; These include: Primary gain and filtering are performed on the received wideband radio frequency signals; Based on the local oscillator signal provided by the local oscillator unit, the primary gain and filtered RF signal are mixed to obtain the intermediate frequency signal. The intermediate frequency signal is subjected to two-stage gain and filtering processing to output the target intermediate frequency signal; S220: Perform controllable attenuation and voltage feedback dynamic adjustment processing on the target intermediate frequency signal to output a stable amplitude control signal; including: The target intermediate frequency signal is controllably attenuated using a two-stage analog attenuator to obtain the intermediate frequency signal. The detector detects the DC voltage in the intermediate frequency signal that varies with the output signal power. The DC voltage and the preset reference voltage are processed by an operational amplifier to obtain the attenuation indication voltage that controls the attenuation value of the two-stage analog attenuator. The reference voltage is determined based on the ambient temperature and a preset compensation frequency.
11. The wideband temperature-compensated amplitude stabilization method for the receiving radio frequency front end as described in claim 10, characterized in that, The mixing process of the primary gain and filtered RF signal based on the local oscillator signal provided by the local oscillator unit includes: Based on the front-loop phase-locked system, the first preset frequency output by the control unit is subjected to front-loop phase-locked processing to obtain the first phase-locked frequency; Based on the phase-locked loop, the first phase-locked frequency is processed by the second preset frequency output by the control unit to obtain the local oscillator signal; The primary filtered radio frequency signal is mixed based on the local oscillator signal.
12. The wideband temperature-compensated amplitude stabilization method for the receiving radio frequency front end as described in claim 11, characterized in that, The reference voltage is determined based on ambient temperature and a preset compensation frequency. The method for determining the reference voltage includes: The reference signal set by the host computer is converted into digital and then into analog signals by two digital-to-analog converters to obtain the first reference voltage and the second reference voltage. The first reference voltage is adjusted according to the ambient temperature to compensate for the output power error caused by temperature changes; and the second reference voltage is adjusted according to a preset compensation frequency to compensate for the output power error caused by frequency changes. The adjusted first reference voltage and the second reference voltage are superimposed to output the reference voltage.