An automatic gain control circuit and RF receiving circuit for IR-UWB communication

Abstract

This invention relates to an automatic gain control (AGC) circuit and an RF receiving circuit for IR-UWB communication, comprising: an adjustable gain amplifier for receiving a signal to be processed, and a first control unit, a second control unit, an AD sampling unit, a sampling threshold setting unit, a signal averaging unit, a first comparison unit, a first loop filter, a second comparison unit, and a second loop filter; the adjustable gain amplifier is connected to the second control unit; the AD sampling unit is connected to the adjustable gain amplifier and the sampling threshold setting unit; the signal averaging unit is connected to the AD sampling unit; the first comparison unit is connected to the signal averaging unit and the first loop filter; the first control unit is connected to the first loop filter and the sampling threshold setting unit; the second comparison unit is connected to the first loop filter and the second loop filter; and the second control unit is connected to the second loop filter. Implementing this invention can reduce circuit area and power consumption while ensuring the performance of the AGC circuit.

Description

Technical Field

[0001] This invention relates to the field of radio frequency technology, and more specifically, to an automatic gain control circuit and a radio frequency receiving circuit for IR-UWB communication. Background Technology

[0002] In wireless communication, the signal power received by the receiver fluctuates due to multipath effects and distance. To address this issue, an Automatic Gain Control (AGC) circuit is needed in the wireless communication system. An AGC circuit is essentially a negative feedback system; the feedback effect means that the output voltage has a reverse effect on the input. AGC circuits have wide practical applications. They can keep the receiver's output voltage amplitude relatively constant while maintaining a certain level of accuracy; they are insensitive to changes in system parameters and have a suitable response speed. A typical communication receiver's AGC circuit consists of a PGA, an ADC, and a digital adjustment circuit. During operation, the digital adjustment circuit adjusts the PGA gain accordingly based on the ADC input value.

[0003] IR-UWB uses a narrow pulse signal, resulting in a higher sampling rate for the corresponding ADC. Many current AGC circuits employ high-precision ADCs to determine signal strength, which increases chip area and power consumption. Therefore, improving the accuracy of the AGC control process is a key challenge in AGC design, aiming to reduce the receiver chip's area and power consumption. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an automatic gain control circuit and an RF receiving circuit for IR-UWB communication.

[0005] The technical solution adopted by the present invention to solve its technical problem is: to construct an automatic gain control circuit for IR-UWB communication, including: an adjustable gain amplifier for receiving the signal to be processed, and a first control unit, a second control unit, an AD sampling unit, a sampling threshold setting unit, a signal averaging unit, a first comparison unit, a first loop filter, a second comparison unit, and a second loop filter.

[0006] The adjustable gain amplifier is connected to the second control unit and is used to receive a second control signal from the second control unit to adjust the output signal corresponding to the signal to be processed.

[0007] The AD sampling unit is connected to the adjustable gain amplifier and the sampling threshold setting unit, and is used to generate a sampling signal corresponding to the output signal according to the sampling threshold generated by the sampling threshold setting unit.

[0008] The signal averaging unit is connected to the AD sampling unit and is used to average the sampled signal according to a preset period to obtain the average value of the sampled signal.

[0009] The first comparison unit is connected to the signal averaging unit and the first loop filter, and is used to obtain a first initial error between the average value of the sampled signal and a first reference value, wherein the first loop filter is used to obtain a first output value based on the first initial error;

[0010] The first control unit is connected to the first loop filter and the sampling threshold setting unit, and is used to generate a first control signal according to the first output value to control the sampling threshold setting unit to generate the sampling threshold.

[0011] The second comparison unit is connected to the first loop filter and the second loop filter, and is used to obtain a second initial error between the first output value and a second reference value, wherein the second loop filter is used to obtain a second output value based on the second initial error;

[0012] The second control unit is connected to the second loop filter and is used to generate the second control signal based on the second output value.

[0013] Preferably, in the automatic gain control circuit of the present invention,

[0014] The sampling threshold includes a first threshold and a second threshold, and the sampling signal includes a first sampling signal that is greater than the first threshold and a second sampling signal that is less than the second threshold;

[0015] The signal averaging unit is used to accumulate and average the first sampled signal according to the preset period to obtain the first sampled signal average value and to accumulate and average the second sampled signal to obtain the second sampled signal average value, and to obtain the average of the absolute values ​​of the first sampled signal average value and the second sampled signal average value as the sampled signal average value.

[0016] Preferably, in the automatic gain control circuit of the present invention, the first threshold is a positive value and the second threshold is a negative value.

[0017] Preferably, in the automatic gain control circuit of the present invention, the sampling threshold setting unit is used to generate the first threshold and the second threshold respectively according to the first control signal, wherein the absolute values ​​of the first threshold and the second threshold are the same.

[0018] Preferably, in the automatic gain control circuit of the present invention, the preset period is the signal period of the signal to be processed.

[0019] Preferably, in the automatic gain control circuit of the present invention, the first loop filter is a proportional-integral filter and / or the second loop filter is a proportional-integral filter.

[0020] Preferably, in the automatic gain control circuit of the present invention, the adjustable gain amplifier is a programmable gain amplifier.

[0021] Preferably, in the automatic gain control circuit of the present invention, the first reference value is adjusted according to the amplitude range of the input signal of the adjustable gain amplifier.

[0022] Preferably, in the automatic gain control circuit of the present invention, the second reference value is adjusted according to the amplitude range of the input signal of the adjustable gain amplifier.

[0023] Furthermore, the present invention also constructs a radio frequency receiving circuit for IR-UWB communication, comprising: a front-end radio frequency receiving unit, a mixing unit connected to the front-end radio frequency receiving unit, and a first gain control circuit connected to the I-channel output of the mixing unit and a second gain control circuit connected to the Q-channel output of the mixing unit; wherein the first gain control circuit and the second gain control circuit are respectively automatic gain control circuits as described in any one of the above.

[0024] The automatic gain control circuit and radio frequency receiving circuit of the present invention applied to IR-UWB communication have the following beneficial effects: they can reduce circuit area and power consumption while ensuring the performance of the AGC circuit. Attached Figure Description

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0026] Figure 1 This is a schematic diagram of an embodiment of an automatic gain control circuit applied to IR-UWB communication according to the present invention. Detailed Implementation

[0027] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0028] like Figure 1As shown, in the first embodiment of the automatic gain control circuit for IR-UWB communication of the present invention, it includes: an adjustable gain amplifier 110 for receiving a signal to be processed, and a first control unit 161, a second control unit 162, an AD sampling unit 120, a sampling threshold setting unit 170, a signal averaging unit 130, a first comparison unit 141, a first loop filter 151, a second comparison unit 142, and a second loop filter 152; the adjustable gain amplifier 110 is connected to the second control unit 162 and is used to receive a second control signal from the second control unit 162 to adjust the output signal corresponding to the signal to be processed; the AD sampling unit 120 is connected to the adjustable gain amplifier 110 and the sampling threshold setting unit 170 and is used to generate a sampling signal corresponding to the output signal according to the sampling threshold generated by the sampling threshold setting unit 170; the signal averaging unit 130 is connected to the AD sampling unit 120 and is used to average the sampling signal according to a preset period to obtain The first comparison unit 141 is connected to the signal averaging unit 130 and the first loop filter 151, and is used to obtain a first initial error between the average value of the sampled signal and a first reference value, wherein the first loop filter 151 is used to obtain a first output value based on the first initial error; the first control unit 161 is connected to the first loop filter 151 and the sampling threshold setting unit 170, and is used to generate a first control signal based on the first output value to control the sampling threshold setting unit 170 to generate the sampling threshold; the second comparison unit 142 is connected to the first loop filter 151 and the second loop filter 152, and is used to obtain a second initial error between the first output value and a second reference value, wherein the second loop filter 152 is used to obtain a second output value based on the second initial error; the second control unit 162 is connected to the second loop filter 152, and is used to generate a second control signal based on the second output value.

[0029] Specifically, the adjustable gain amplifier 110 adjusts its gain according to the second control signal received from the second control unit 162 to ultimately adjust the amplification process of the signal to be processed, thereby obtaining the corresponding output signal. The AD sampling unit 120 is connected to the adjustable gain amplifier 110 and the sampling threshold setting unit 170. It is used to control the sampling process of the output signal of the adjustable gain amplifier 110 according to the sampling threshold generated by the sampling threshold setting unit 170, thereby obtaining the corresponding sampled signal. The signal averaging unit 130 averages the sampled signal according to a preset rule to obtain the average value of the sampled signal. The first comparison unit 141 compares the average value of the sampled signal with a first reference value to obtain the first initial error of the average value of the sampled signal relative to the first reference value. The first loop filter 151 preprocesses the first output value according to the first initial error to obtain the first output value. The first control unit 161 adjusts the first control signal according to the obtained first output value to control the sampling threshold setting unit 170 to generate the corresponding sampling threshold. That is, the first control unit 161 forms a feedback loop to control the operation of the AD sampling unit 120, so that the sampling result of the AD sampling unit 120 can more accurately approximate the input signal. The AD sampling unit inputs the sampled signal to the baseband processing circuit for receiving signal to ultimately demodulate the received signal. The first comparison unit 141 and the first loop filter 151 allow control of the sampling threshold of the AD sampling unit 120 within the acceptable signal range of its operation.

[0030] In one embodiment, the first reference value is adjusted according to the amplitude range of the input signal of the adjustable gain amplifier. That is, the first reference value can be adjusted by the user according to the amplitude range of the input signal of the adjustable gain amplifier. The purpose is to ensure that the sampling threshold of the AD sampling unit 120 is within the normal operating range of the AD sampling unit 120 as much as possible.

[0031] The second comparison unit 142 compares the first output value with a second reference value to obtain a comparison result of the first output value relative to the second reference value, i.e., to obtain the second initial error of the first output value relative to the second reference value. This second initial error is then preprocessed by the second loop filter 152 to obtain the second output value. The second control unit 162 generates a corresponding second control signal based on this second output value. This ultimately achieves gain control of the adjustable gain controller, realizing the automatic gain control process of the receiving link of the signal to be processed. Through the second comparison unit 142 and the second loop filter 152, when the output value of the adjustable gain amplifier 110 exceeds the acceptable signal range of the AD sampling unit 120, the output signal can be restored to the controllable range of the AD sampling unit 120 by controlling the gain of the adjustable gain amplifier 110.

[0032] In one embodiment, the second reference value is adjusted according to the amplitude range of the input signal of the adjustable gain amplifier. That is, the second reference value can be adjusted by the user according to the amplitude range of the input signal of the adjustable gain amplifier. The purpose is to ensure that the input of the AD sampling unit 120 is within the acceptable range of the AD sampling unit 120 as much as possible.

[0033] Optionally, the sampling threshold includes a first threshold and a second threshold, and the sampling signal includes a first sampling signal greater than the first threshold and a second sampling signal less than the second threshold. The signal averaging unit 130 is used to accumulate and average the first sampling signal according to the preset period to obtain the average value of the first sampling signal and to accumulate and average the second sampling signal to obtain the average value of the second sampling signal, and to obtain the average of the absolute values ​​of the first sampling signal average value and the second sampling signal average value as the average value of the sampling signal. Specifically, during the operation of the AD sampling unit 120, a reasonable sampling threshold can be set to obtain the sampling signal of the output signal. Since the input signal can be understood as approximately a sine wave, it can set corresponding sampling thresholds according to its peaks and troughs, that is, the first sampling signal greater than the first threshold is obtained through the first threshold, and the second sampling signal less than the second threshold is obtained according to the second threshold. The process of the signal averaging unit 130 obtaining the average value of the sampling signal can be understood as accumulating and averaging the first sampling signal within the preset period to obtain the average value of the first sampling signal, accumulating and averaging the second sampling signal within the preset period to obtain the average value of the second sampling signal, obtaining the average of the absolute values ​​of the two average values ​​of the sampling signal, and finally obtaining the average value of the sampling signal.

[0034] Optionally, the first threshold is positive and the second threshold is negative. This means that the signal to be processed is a normalized AC signal that has been de-DCed. In this case, the first threshold can be set to a positive value to sample the positive waveform of the AC signal, and the second threshold can be set to a negative value to sample the negative waveform of the AC signal.

[0035] Optionally, the sampling threshold setting unit 170 is used to generate a first threshold and a second threshold respectively according to the first control signal, wherein the absolute values ​​of the first threshold and the second threshold are the same. The process of the sampling threshold setting unit generating the first threshold and the second threshold is as follows: generating an absolute value, directly setting the absolute value as the first threshold, adding a negative value to the absolute value to obtain a negative value, and setting the negative value as the second threshold.

[0036] Optionally, the preset period is the signal period of the signal to be processed. Optionally, the adjustment process of the adjustable gain amplifier 110 can be periodic, with each adjustment period mainly set according to the periodicity of the input signal to be processed. For example, if the input signal to be processed is an IEEE 802.15.4z UWB signal, the period of each symbol is approximately 1µs, and the corresponding adjustment period can be 1µs. In each adjustment period, the sampling threshold control of the AD sampling unit 120 and the amplification gain control of the adjustable gain amplifier 110 are performed respectively.

[0037] Optionally, the first loop filter 151 is a proportional-integral (PI) filter. Specifically, the loop filter includes proportional and integral components to reduce the impact of noise through the integral component. This PPI filter can be represented as kp_dac*error1+sum(ki_dac*error1), where error1 is the first initial error. kp_dac is the coefficient of the proportional component, and ki_dac is the coefficient of the integral component; these constants can be set according to the operating parameters of the AD sampling unit 120.

[0038] Optionally, the second loop filter 152 is a proportional-integral (PI) filter. Specifically, the structure of this PPI filter can be kp_pga*error2 + sum(ki_pga*error2). The second control unit 162 is used to generate a second control signal based on the output of this loop filter, ultimately achieving the purpose of setting the amplification amplitude of the baseband signal. Here, error2 is the second initial error. kp_pga is the coefficient of the proportional element, and ki_pga is the coefficient of the integral element; both can be set as constants according to the operating parameters of the adjustable gain amplifier 110.

[0039] Optionally, the adjustable gain amplifier 110 is a programmable gain amplifier. That is, the second control unit 162 is used to set the control word of the programmable gain amplifier, and its control process needs to ensure that it is within the adjustment range of the programmable gain amplifier. In other words, the generation process of the second control signal needs to take into account the full scale of the programmable gain amplifier and its adjustment step.

[0040] Similarly, it can be understood that the process of the first control unit 161 generating the first control signal also needs to take into account the full-scale range of the AD sampling unit 120 and its adjustment step to obtain the most reasonable first control signal. Since the AD sampling unit 120 can sample the input signal of the ADC module in the link, this process ensures that the input signal of the ADC module is within a reasonable range. Therefore, when the control process of the first control unit 161 exceeds the acceptable signal range of the ADC, the gain of the adjustable gain amplifier can be controlled by the second control unit 162 to restore the signal entering the ADC back to the controllable range of the ADC. Furthermore, the AD sampling unit 120 can be integrated into the ADC module.

[0041] Additionally, in a radio frequency receiving circuit for IR-UWB communication according to the present invention, there are: a front-end radio frequency receiving unit, a mixer unit connected to the front-end radio frequency receiving unit, and a first gain control circuit connected to the I-channel output of the mixer unit and a second gain control circuit connected to the Q-channel output of the mixer unit; wherein the first gain control circuit and the second gain control circuit are respectively automatic gain control circuits as described in any one of the above claims.

[0042] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. An automatic gain control circuit for IR-UWB communication, characterized in that, include: An adjustable gain amplifier for receiving signals to be processed, as well as a first control unit, a second control unit, an AD sampling unit, a sampling threshold setting unit, a signal averaging unit, a first comparison unit, a first loop filter, a second comparison unit, and a second loop filter; The adjustable gain amplifier is connected to the second control unit and is used to receive a second control signal from the second control unit to adjust the output signal corresponding to the signal to be processed. The AD sampling unit is connected to the adjustable gain amplifier and the sampling threshold setting unit, and is used to generate a sampling signal corresponding to the output signal according to the sampling threshold generated by the sampling threshold setting unit. The signal averaging unit is connected to the AD sampling unit and is used to average the sampled signal according to a preset period to obtain the average value of the sampled signal. The first comparison unit is connected to the signal averaging unit and the first loop filter, and is used to obtain a first initial error between the average value of the sampled signal and a first reference value, wherein the first loop filter is used to obtain a first output value based on the first initial error; The first control unit is connected to the first loop filter and the sampling threshold setting unit, and is used to generate a first control signal according to the first output value to control the sampling threshold setting unit to generate the sampling threshold. The second comparison unit is connected to the first loop filter and the second loop filter, and is used to obtain a second initial error between the first output value and a second reference value, wherein the second loop filter is used to obtain a second output value based on the second initial error; The second control unit is connected to the second loop filter and is used to generate the second control signal based on the second output value.

2. The automatic gain control circuit according to claim 1, characterized in that, The sampling threshold includes a first threshold and a second threshold, and the sampling signal includes a first sampling signal that is greater than the first threshold and a second sampling signal that is less than the second threshold; The signal averaging unit is used to accumulate and average the first sampled signal according to the preset period to obtain the first sampled signal average value and to accumulate and average the second sampled signal to obtain the second sampled signal average value, and to obtain the average of the absolute values ​​of the first sampled signal average value and the second sampled signal average value as the sampled signal average value.

3. The automatic gain control circuit according to claim 2, characterized in that, The first threshold is a positive value, and the second threshold is a negative value.

4. The automatic gain control circuit according to claim 3, characterized in that, The sampling threshold setting unit is used to generate the first threshold and the second threshold respectively according to the first control signal, wherein the absolute values ​​of the first threshold and the second threshold are the same.

5. The automatic gain control circuit according to claim 1, characterized in that, The preset period is the signal period of the signal to be processed.

6. The automatic gain control circuit according to claim 1, characterized in that, The first loop filter is a proportional-integral filter and / or the second loop filter is a proportional-integral filter.

7. The automatic gain control circuit according to claim 1, characterized in that, The adjustable gain amplifier is a programmable gain amplifier.

8. The automatic gain control circuit according to claim 1, characterized in that, The first reference value is adjusted according to the amplitude range of the input signal of the adjustable gain amplifier.

9. The automatic gain control circuit according to claim 1, characterized in that, The second reference value is adjusted according to the amplitude range of the input signal of the adjustable gain amplifier.

10. A radio frequency receiving circuit for IR-UWB communication, characterized in that, include: A front-end radio frequency receiving unit, a mixer unit connected to the front-end radio frequency receiving unit, a first gain control circuit connected to the I-channel output of the mixer unit, and a second gain control circuit connected to the Q-channel output of the mixer unit; wherein the first gain control circuit and the second gain control circuit are respectively the automatic gain control circuits according to any one of claims 1 to 9.

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