Radio frequency transceiver gain flatness adaptive calibration circuit and method

Abstract

The invention discloses a radio frequency transceiver gain flatness adaptive calibration circuit and method, and relates to the technical field of radio frequency circuits. According to the invention, the gain flatness self-adaptive calibration circuit is introduced into the radio frequency receiving or transmitting channel, so that after the circuit is manufactured, the gain flatness of the radio frequency channel can be automatically detected and calibrated, and the adverse effects of process deviation, power supply voltage change and temperature fluctuation (PVT) on the gain flatness of the radio frequency receiving or transmitting channel are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of radio frequency circuits, and in particular to a circuit and method for adaptively calibrating gain flatness of a radio frequency transceiver. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0003] RF transceivers are widely used in modern communication systems and phased array systems. In order to achieve long-distance communication, the receiver is usually required to linearly amplify the weak signal received by the antenna under a certain power consumption to meet the requirements of the signal processing of the subsequent circuit; the transmitter is usually required to be able to amplify the signal power while maintaining high efficiency and no distortion; in the phased array system, the RF transceiver electronically controls the signal amplitude and phase of each unit of the antenna, which can realize the control of beam shape and direction, multi-target tracking, etc.

[0004] Gain flatness characterizes the gain fluctuation of the RF circuit within a certain frequency band and describes the signal amplitude distortion characteristics within the frequency band. This indicator is particularly important in broadband RF systems. In RF circuit design, due to the precision limitation of the manufacturing process (P), there will always be a deviation between the actual value and the designed value of each component; when the circuit scale is large, the cumulative effect of the deviation of active and passive components will cause a large deviation between the actual value and the designed value of the circuit gain flatness. At the same time, when the circuit is working, temperature (T) fluctuations and power supply voltage (V) changes will have a certain impact on the device parameters and deteriorate the gain flatness. When the circuit is designed using discrete components, components that meet the circuit gain flatness can be found through screening; in integrated circuit design, circuit parameters are usually adjusted through multiple tape-outs to meet the design requirements of parameters such as gain flatness. However, the screening of discrete components or multiple tape-outs of chips will increase product development costs and extend the product development cycle. Summary of the invention

[0005] The purpose of the present invention is to provide a gain flatness adaptive calibration circuit and method for a radio frequency transceiver in response to the problems existing in the prior art. By introducing a gain flatness adaptive calibration circuit in a radio frequency receiving or transmitting channel, after the circuit is manufactured, the gain flatness of the radio frequency channel can be automatically detected and calibrated, thereby improving the adverse effects of process deviations, power supply voltage changes, and temperature fluctuations (PVT) on the gain flatness of the radio frequency transceiver channel.

[0006] The technical solution of the present invention is as follows:

[0007] A radio frequency transceiver gain flatness adaptive calibration circuit, comprising:

[0008] A radio frequency signal generating circuit, a digital control circuit, a digital-to-analog conversion circuit, a power detection circuit, a gain slope adjustment circuit, a first radio frequency circuit, and a second radio frequency circuit;

[0009] The gain slope adjustment circuit is connected in series between the first RF circuit and the second RF circuit in the RF channel; the power detection circuit, the digital-to-analog conversion circuit, the digital control circuit, and the RF signal generating circuit are connected in series in sequence; the power detection circuit is connected to the RF output of the RF channel; the digital control circuit is connected to the gain slope adjustment circuit; and the RF signal generating circuit is connected to the RF input of the RF channel.

[0010] Furthermore, the first RF circuit and the second RF circuit have a RF signal processing function.

[0011] Furthermore, the radio frequency signal processing function includes:

[0012] One or more of the attenuation, amplification, phase shift, filtering, power combination / power division, and mixing functional units.

[0013] Furthermore, the gain slope adjustment circuit can adjust the gain flatness of the radio frequency channel under the action of the digital control circuit.

[0014] Furthermore, the power detection circuit detects the power amplitude of the radio frequency signal output by the radio frequency channel, and the digital-to-analog conversion circuit converts the analog signal output by the power detection circuit into a digital signal.

[0015] Furthermore, the digital control circuit obtains the RF channel gain flatness according to the digital signal, and compares it with a desired flatness threshold, and controls the gain slope adjustment circuit to adjust the RF channel gain flatness according to the comparison result.

[0016] Furthermore, the digital control circuit also controls the radio frequency signal generating circuit to generate radio frequency signals with different frequencies and constant amplitudes as test signals to be input into the radio frequency channel.

[0017] The present invention also proposes a method for adaptively calibrating the gain flatness of a radio frequency transceiver, based on the above-mentioned adaptive calibration circuit for gain flatness of a radio frequency transceiver, comprising:

[0018] The gain slope adjustment circuit adjusts the gain flatness of the RF channel under the action of the digital control circuit; the power detection circuit detects the power amplitude of the RF signal output by the RF channel, the digital-to-analog conversion circuit converts the analog signal output by the power detection circuit into a digital signal, the digital control circuit obtains the gain flatness of the RF channel according to the digital signal, and compares it with the expected flatness threshold, controls the gain slope adjustment circuit to adjust the gain flatness of the RF channel according to the comparison result, and controls the RF signal generation circuit to generate RF signals of different frequencies and constant amplitudes as test signals to input into the RF channel.

[0019] Furthermore, a method for adaptively calibrating gain flatness of a radio frequency transceiver comprises the following specific steps:

[0020] Step S1: After calibration begins, the digital control circuit is initialized;

[0021] Step S2: Under the action of the output signal of the digital control circuit, the gain slope adjustment circuit initializes the gain slope of the RF channel, and the RF signal generation circuit outputs a RF signal with a frequency of f1 and a power of P0; the variable j is used to store the number of gain slope adjustments, and the variable i is used to store the number of times the test signal is input and the output power is sampled at the current gain slope after each gain slope adjustment;

[0022] Step S3: assign a value of 1 to variable j, assign a value of 1 to variable i, and determine whether j is greater than m; a maximum of m slope adjustments can be performed, and each slope adjustment performs RF channel gain flatness test signal input, output power detection, digital-to-analog conversion, and storage of output RF signal power amplitude information;

[0023] Step S4: Perform adaptive calibration according to the judgment result.

[0024] Furthermore, the step S4 comprises:

[0025] When j is greater than m, it means that after m times of gain slope adjustment, the gain flatness still does not meet expectations. At this time, the flatness adjustment is terminated, and the best flatness during the m times of slope adjustment is taken as the final flatness adjustment result.

[0026] If j is less than or equal to m, increase j by 1, and then determine whether i is greater than n, where n is the frequency range f1 to f nThe number of test signal frequency points within the RF channel; if i is greater than n, it means that under the current gain slope, the RF channel has completed n times of P0 test signal input with different frequencies and the same power, output power detection, digital-to-analog conversion, and saved the output RF signal power amplitude information, and can calculate the gain flatness and gain slope. If the gain flatness is less than the set flatness threshold, the algorithm ends, and the current gain slope is the adjusted final gain slope; if the expected gain flatness is not achieved, the digital control circuit outputs a signal to act on the gain slope adjustment circuit to adjust the RF channel gain slope, and at the same time controls the RF signal generation circuit to successively generate n test signals with different frequencies and the same power to input into the RF channel, perform output power detection, digital-to-analog conversion, and save the output RF signal power amplitude information, recalculate the RF channel gain flatness and gain slope, and again determine whether the RF channel gain slope meets the requirements.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) Under loop control, the gain flatness of the RF transceiver can be adaptively calibrated; after the circuit is manufactured, the gain flatness of the RF transceiver channel can be optimized, reducing product development costs and shortening product development cycles;

[0029] (2) It can reduce the impact of process, power supply, and temperature fluctuations on RF channel performance;

[0030] (3) The circuit is simple, easy to implement and has good engineering practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of a gain flatness adaptive calibration circuit of a radio frequency transceiver of the present invention;

[0032] Figure 2 It is a schematic diagram of a gain curve of a gain flatness adaptive calibration circuit of a radio frequency transceiver of the present invention;

[0033] Figure 3 The present invention is a schematic diagram of a RF transceiver gain flatness adaptive calibration process Figure 1 ;

[0034] Figure 4 The present invention is a schematic diagram of a RF transceiver gain flatness adaptive calibration process Figure 2 ;

[0035] Figure 5 The present invention is a schematic diagram of a flow chart of a gain flatness adaptive calibration algorithm for a radio frequency transceiver. DETAILED DESCRIPTION

[0036] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0037] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0038] Embodiment 1

[0039] See also Figure 1 , a radio frequency transceiver gain flatness adaptive calibration circuit, comprising:

[0040] A radio frequency signal generating circuit, a digital control circuit, a digital-to-analog conversion circuit, a power detection circuit, a gain slope adjustment circuit, a first radio frequency circuit, and a second radio frequency circuit;

[0041] The gain slope adjustment circuit is connected in series between the first RF circuit and the second RF circuit in the RF channel; the power detection circuit, the digital-to-analog conversion circuit, the digital control circuit, and the RF signal generating circuit are connected in series in sequence; the power detection circuit is connected to the RF output of the RF channel; the digital control circuit is connected to the gain slope adjustment circuit; and the RF signal generating circuit is connected to the RF input of the RF channel.

[0042] In this embodiment, specifically, the first RF circuit and the second RF circuit have RF signal processing functions, including: one or more of attenuation, amplification, phase shift, filtering, power combination / power division, and mixing functional units.

[0043] In this embodiment, specifically, the gain slope adjustment circuit can adjust the gain flatness of the RF channel under the action of the digital control circuit. The power detection circuit detects the power amplitude of the RF signal output by the RF channel, and the digital-to-analog conversion circuit converts the analog signal output by the power detection circuit into a digital signal. The digital control circuit obtains the gain flatness of the RF channel according to the digital signal, and compares it with the desired flatness threshold, and controls the gain slope adjustment circuit to adjust the gain flatness of the RF channel according to the comparison result. The digital control circuit also controls the RF signal generation circuit to generate RF signals of different frequencies and constant amplitudes as test signals to input into the RF channel.

[0044] See also Figure 2 , a schematic diagram of a gain curve of a gain flatness adaptive calibration circuit of a radio frequency transceiver. Curve a represents the gain curve of the gain slope adjustment circuit in the radio frequency channel; curve b represents the circuit other than the gain slope adjustment circuit in the radio frequency channel, i.e., the overall gain curve of the first radio frequency circuit and the second radio frequency circuit; curve c represents the gain curve of the entire radio frequency channel formed by superimposing curve a and curve b; the shaded part of curve c is the frequency range f1~f n The optimal flatness condition is the gain curve expected in the circuit design stage; optionally, Figure 2 In (a), the center frequency of curve a is higher than that of curve b. Figure 2 In (b), the center frequency of curve a is lower than that of curve b.

[0045] See also Figure 3 Schematic diagram of a RF transceiver gain flatness adaptive calibration process of the present invention Figure 1 , curve a j The center frequency is higher than curve b, j is a natural number, 1≤j≤m, m is defined as the maximum number of slope adjustments, for ease of description, Figure 3 The number of mid-slope adjustments is described by the maximum value m.

[0046] See also Figure 3 (a). Optionally, assuming that after the RF channel circuit is manufactured, due to PVT fluctuations, the gain curve of the gain slope adjustment circuit is a1, the overall gain curve of the first RF circuit and the second RF circuit is b, and the RF channel gain curve after the superposition of curves a1 and b is c1, with a frequency range of f1 to f n The internal gain has a positive slope, high-frequency gain is high, and low-frequency gain is low; the slope adjustment circuit is configured through the digital control circuit, and its gain curve is adjusted to a2, the total gain curve of the RF channel is c2, the positive slope of the gain decreases, and the flatness becomes better; continue to adjust in the same direction, after m times of adjustment, the gain curve of the slope adjustment circuit is adjusted to a m , the total gain curve of the RF channel is c m, the gain flatness reaches the expectation, that is, the in-band gain fluctuation is less than the expected flatness threshold.

[0047] See also Figure 3 (b). Optionally, assuming that after the RF channel circuit is manufactured, due to PVT fluctuations, the gain curve of the gain slope adjustment circuit is a1, the overall gain curve of the first RF circuit and the second RF circuit is b, and the RF channel gain curve after the superposition of curves a1 and b is c1, with a frequency range of f1 to f n The internal gain has a negative slope, the high-frequency gain is low, and the low-frequency gain is high; the slope adjustment circuit is configured by the digital control circuit, and its gain curve is adjusted to a2, the total gain curve of the RF channel is c2, the negative slope of the gain decreases, and the flatness becomes better; continue to adjust in the same direction, after m times of adjustment, the gain curve of the slope adjustment circuit is adjusted to a m , the total gain curve of the RF channel is c m , the gain flatness reaches the expectation, that is, the in-band gain fluctuation is less than the expected flatness threshold.

[0048] See also Figure 4 Schematic diagram of a RF transceiver gain flatness adaptive calibration process of the present invention Figure 2 , curve a j The center frequency is lower than curve b, j is a natural number, 1≤j≤m, m is defined as the maximum number of slope adjustments, for the convenience of description, Figure 4 The number of mid-slope adjustments is described by the maximum value m.

[0049] See also Figure 4 (a). Optionally, assuming that after the RF channel circuit is manufactured, due to PVT fluctuations, the gain curve of the gain slope adjustment circuit is a1, the overall gain curve of the first RF circuit and the second RF circuit is b, and the RF channel gain curve after the superposition of curves a1 and b is c1, with a frequency range of f1 to f n The internal gain has a negative slope, the high-frequency gain is low, and the low-frequency gain is high; the slope adjustment circuit is configured by the digital control circuit, and its gain curve is adjusted to a2, the total gain curve of the RF channel is c2, the negative slope of the gain decreases, and the flatness becomes better; continue to adjust in the same direction, after m times of adjustment, the gain curve of the slope adjustment circuit is adjusted to a m , the total gain curve of the RF channel is c m , the gain flatness reaches the expectation, that is, the in-band gain fluctuation is less than the expected flatness threshold.

[0050] See also Figure 4 (b). Optionally, assuming that after the RF channel circuit is manufactured, due to PVT fluctuations, the gain curve of the gain slope adjustment circuit is a1, the overall gain curve of the first RF circuit and the second RF circuit is b, and the RF channel gain curve after the superposition of curves a1 and b is c1, with a frequency range of f1 to f nThe internal gain has a positive slope, high-frequency gain is high, and low-frequency gain is low; the slope adjustment circuit is configured through the digital control circuit, and its gain curve is adjusted to a2, the total gain curve of the RF channel is c2, the positive slope of the gain decreases, and the flatness becomes better; continue to adjust in the same direction, after m times of adjustment, the gain curve of the slope adjustment circuit is adjusted to a m , the total gain curve of the RF channel is c m , the gain flatness reaches the expectation, that is, the in-band gain fluctuation is less than the expected flatness threshold.

[0051] Based on the above-mentioned RF transceiver gain flatness adaptive calibration circuit, this embodiment further proposes a RF transceiver gain flatness adaptive calibration method, including:

[0052] The gain slope adjustment circuit adjusts the gain flatness of the RF channel under the action of the digital control circuit; the power detection circuit detects the power amplitude of the RF signal output by the RF channel, the digital-to-analog conversion circuit converts the analog signal output by the power detection circuit into a digital signal, the digital control circuit obtains the gain flatness of the RF channel according to the digital signal, and compares it with the expected flatness threshold, and controls the gain slope adjustment circuit to adjust the gain flatness of the RF channel according to the comparison result; at the same time, the RF signal generation circuit is controlled to generate RF signals of different frequencies and constant amplitudes as test signals to input into the RF channel.

[0053] See also Figure 5 In this embodiment, specifically, a method for adaptively calibrating gain flatness of a radio frequency transceiver includes the following specific steps:

[0054] Step S1: After calibration begins, the digital control circuit is initialized;

[0055] Step S2: Under the action of the output signal of the digital control circuit, the gain slope adjustment circuit initializes the gain slope of the RF channel, and the RF signal generation circuit outputs a RF signal with a frequency of f1 and a power of P0; the variable j is used to store the number of gain slope adjustments, and the variable i is used to store the number of times the test signal is input and the output power is sampled at the current gain slope after each gain slope adjustment;

[0056] Step S3: assign a value of 1 to variable j, assign a value of 1 to variable i, and determine whether j is greater than m; a maximum of m slope adjustments can be performed, and each slope adjustment performs RF channel gain flatness test signal input, output power detection, digital-to-analog conversion, and storage of output RF signal power amplitude information;

[0057] Step S4: Perform adaptive calibration according to the judgment result.

[0058] In this embodiment, specifically, step S4 includes:

[0059] When j is greater than m, it means that after m times of gain slope adjustment, the gain flatness still does not meet expectations. At this time, the flatness adjustment is terminated, and the best flatness during the m times of slope adjustment is taken as the final flatness adjustment result.

[0060] If j is less than or equal to m, increase j by 1, and then determine whether i is greater than n, where n is the frequency range f1 to f n The number of test signal frequency points within the RF channel; if i is greater than n, it means that under the current gain slope, the RF channel has completed n times of P0 test signal input with different frequencies and the same power, output power detection, digital-to-analog conversion, and saved the output RF signal power amplitude information, and can calculate the gain flatness and gain slope. If the gain flatness is less than the set flatness threshold, the algorithm ends, and the current gain slope is the adjusted final gain slope; if the expected gain flatness is not achieved, the digital control circuit outputs a signal to act on the gain slope adjustment circuit to adjust the RF channel gain slope, and at the same time controls the RF signal generation circuit to successively generate n test signals with different frequencies and the same power to input into the RF channel, perform output power detection, digital-to-analog conversion, and save the output RF signal power amplitude information, recalculate the RF channel gain flatness and gain slope, and again determine whether the RF channel gain slope meets the requirements.

[0061] The above-mentioned embodiments only express the specific implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the protection scope of the present application. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the technical solution concept of the present application, and these all belong to the protection scope of the present application.

[0062] This background section is provided to generally present the context of the invention, and the work of the presently named inventors, the work to the extent described in this background section, and aspects of this section that did not constitute prior art at the time of application are neither explicitly nor implicitly admitted to be prior art to the present invention.

Claims

1. A radio frequency transceiver gain flatness adaptive calibration circuit, characterized in that: include: A radio frequency signal generating circuit, a digital control circuit, a digital-to-analog conversion circuit, a power detection circuit, a gain slope adjustment circuit, a first radio frequency circuit, and a second radio frequency circuit; The gain slope adjustment circuit is connected in series between the first RF circuit and the second RF circuit in the RF channel; the power detection circuit, the digital-to-analog conversion circuit, the digital control circuit, and the RF signal generating circuit are connected in series in sequence; the power detection circuit is connected to the RF output of the RF channel; the digital control circuit is connected to the gain slope adjustment circuit; and the RF signal generating circuit is connected to the RF input of the RF channel.

2. The RF transceiver gain flatness adaptive calibration circuit according to claim 1, characterized in that: The first RF circuit and the second RF circuit have a RF signal processing function.

3. The RF transceiver gain flatness adaptive calibration circuit according to claim 2, characterized in that: The radio frequency signal processing function includes: One or more of the attenuation, amplification, phase shift, filtering, power combination / power division, and mixing functional units.

4. The RF transceiver gain flatness adaptive calibration circuit according to claim 1, characterized in that: The gain slope adjustment circuit can adjust the gain flatness of the radio frequency channel under the action of the digital control circuit.

5. The RF transceiver gain flatness adaptive calibration circuit according to claim 4, characterized in that: The power detection circuit detects the power amplitude of the radio frequency signal output by the radio frequency channel, and the digital-to-analog conversion circuit converts the analog signal output by the power detection circuit into a digital signal.

6. The RF transceiver gain flatness adaptive calibration circuit according to claim 5, characterized in that: The digital control circuit obtains the RF channel gain flatness according to the digital signal, and compares it with the expected flatness threshold, and controls the gain slope adjustment circuit to adjust the RF channel gain flatness according to the comparison result.

7. The RF transceiver gain flatness adaptive calibration circuit according to claim 6, characterized in that: The digital control circuit also controls the radio frequency signal generating circuit to generate radio frequency signals with different frequencies and constant amplitudes as test signals to be input into the radio frequency channel.

8. A method for adaptively calibrating gain flatness of a radio frequency transceiver, characterized in that: A radio frequency transceiver gain flatness adaptive calibration circuit according to any one of claims 1 to 7, comprising: The gain slope adjustment circuit adjusts the gain flatness of the RF channel under the action of the digital control circuit; the power detection circuit detects the power amplitude of the RF signal output by the RF channel, the digital-to-analog conversion circuit converts the analog signal output by the power detection circuit into a digital signal, the digital control circuit obtains the gain flatness of the RF channel according to the digital signal, and compares it with the expected flatness threshold, controls the gain slope adjustment circuit to adjust the gain flatness of the RF channel according to the comparison result, and controls the RF signal generation circuit to generate RF signals of different frequencies and constant amplitudes as test signals to input into the RF channel.

9. The method for adaptively calibrating gain flatness of a radio frequency transceiver according to claim 8, characterized in that: The specific steps include: Step S1: After calibration begins, the digital control circuit is initialized; Step S2: Under the action of the output signal of the digital control circuit, the gain slope adjustment circuit initializes the gain slope of the RF channel, and the RF signal generation circuit outputs a RF signal with a frequency of f1 and a power of P0; The variable j is used to store the number of times the gain slope is adjusted, and the variable i is used to store the number of times the test signal is input and the output power is sampled at the current gain slope after each gain slope adjustment; Step S3: assign a value of 1 to variable j, assign a value of 1 to variable i, and determine whether j is greater than m; a maximum of m slope adjustments can be performed, and each slope adjustment performs RF channel gain flatness test signal input, output power detection, digital-to-analog conversion, and storage of output RF signal power amplitude information; Step S4: Perform adaptive calibration according to the judgment result.

10. The method for adaptively calibrating gain flatness of a radio frequency transceiver according to claim 9, characterized in that: The step S4 comprises: When j is greater than m, it means that after m times of gain slope adjustment, the gain flatness still does not meet expectations. At this time, the flatness adjustment is terminated, and the best flatness during the m times of slope adjustment is taken as the final flatness adjustment result. If j is less than or equal to m, increase j by 1, and then determine whether i is greater than n, where n is the frequency range f1 to f n The number of test signal frequency points within the RF channel; if i is greater than n, it means that under the current gain slope, the RF channel has completed n times of P0 test signal input with different frequencies and the same power, output power detection, digital-to-analog conversion, and saved the output RF signal power amplitude information, and can calculate the gain flatness and gain slope. If the gain flatness is less than the set flatness threshold, the algorithm ends, and the current gain slope is the adjusted final gain slope; if the expected gain flatness is not achieved, the digital control circuit output signal acts on the gain slope adjustment circuit to adjust the RF channel gain slope, and at the same time controls the RF signal generation circuit to successively generate n test signals with different frequencies and the same power to input into the RF channel, perform output power detection, digital-to-analog conversion, and save the output RF signal power amplitude information, recalculate the RF channel gain flatness and gain slope, and again determine whether the RF channel gain slope meets the requirements.

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