TWI461033B - ASK / OOK RF reception circuit - Google Patents

Description

ASK/OOK RF receiving circuit

The present invention relates to the field of signal and information processing, and more particularly to radio frequency receiving technology.

Traditional remote control circuits, such as toy car remote control circuits, door and window remote control circuits, etc., use ASK/OOK modulation, and their receiving circuits generally have two implementations of super-regenerative circuits and super-heterodyne circuits. The super-regenerative circuit is widely used due to its low cost, simple circuit and high sensitivity, but it has problems such as difficulty in integration and weak anti-interference ability compared with super-heterodyne structure.

The structure of a superheterodyne RF receiving circuit is shown in Figure 1. The signal received by the antenna is amplified by a low noise amplifier (11) and passed through a mixer together with a local oscillator signal generated by the local oscillator (17). Down-converted to the intermediate frequency, and then amplified by the first-stage IF amplifier (13), the mid-band pass filter (14) filter, and the second-stage IF amplifier (15), and then demodulated by the peak detection module (16). Give the latter digital decoding circuit. The superheterodyne receiving circuit is easy to integrate, has better circuit stability and stronger anti-interference ability, but there is a problem of signal blocking in practical applications. In remote control applications, depending on the transceiver distance, the size of the signal received by the antenna can vary from less than -100 dBm to a wide range of approximately 0 dBm. In order to ensure the sensitivity of the RF receiving circuit, the total gain of the RF receiving circuit consisting of low noise amplifier gain, mixer gain, primary IF amplifier gain, secondary IF amplifier gain and filter gain needs to reach about 100 dB. When the amplitude of the signal received by the antenna is large, if the gain value is kept unchanged, some circuits in the RF receiving circuit will work in a large signal state, and the circuit nonlinearity reaches a certain level in the large signal state, which will result in the superheterodyne RF receiving circuit failing. normal work. The range of signals in which the RF receiving circuit works normally is called the dynamic range of the system, so the above phenomenon is actually the insufficient dynamic range of the RF receiving circuit. In the actual application, when the remote control distance is very close, there is a state that cannot respond, and the signal is "blocked" because it is too large.

A general method for solving the problem that the dynamic range of the RF receiving circuit is insufficient is to increase the gain control. By detecting the size of the received signal and feeding back, the gain of each part of the RF receiving circuit is controlled to be reduced to an appropriate value, thereby reducing the nonlinearity of the circuit. Since no external control is required, this feedback circuit is generally referred to as an automatic gain control loop (AGC loop). At present, the automatic gain control loop has various implementation modes, such as using an analog digital converter to detect the signal size, controlling the logic switch to change the gain size of the pure digit mode (as shown in FIG. 2), or using the peak detection module to obtain the signal size feedback back. The analogy of the gain of the control circuit, or the way analog and digital are mixed, and so on. Each of the above methods has a wide range of applications, but the digital method uses an analog-to-digital converter, which occupies a large wafer area and power consumption, which is not conducive to cost reduction; and analogy, in order to ensure the sensitivity of the receiving circuit is not Loss, generally only the gain of the IF amplifier or mixer, and to increase the gain of the low noise amplifier to obtain a higher dynamic range, usually through a complex gain controller The feedback signal is operated to control the gain of each unit separately (as shown in Figure 3).

The invention aims to solve the deficiencies of the prior art, and provides an ASK/OOK radio frequency receiving circuit with strong anti-interference ability, high sensitivity and low cost for the characteristics of ASK/OOK modulation.

The ASK/OOK RF receiving circuit includes: a low noise amplifier, an oscillator, a mixer, a first-order intermediate frequency amplifier, a medium-frequency pass filter, a secondary intermediate frequency amplifier, a peak detection module, a comparator, a charge pump, and a capacitor; The low noise amplifier amplifies the signal received by the antenna and inputs the mixer together with the local oscillator generated by the oscillator, and the mixer reduces the frequency of the low noise amplifier output to the intermediate frequency, and the mixer The output intermediate frequency signal is further amplified by a first-stage intermediate frequency amplifier, filtered by a medium-frequency band filter, and amplified by a second-stage intermediate frequency amplifier, and then demodulated and outputted by a peak detection module, and the peak detection output is compared with a fourth reference potential Vref4, according to comparison. As a result of charging, the capacitor is charged and discharged to obtain a gain control signal Vagc, and the gain control signal Vagc is fed back to the low noise amplifier, the first intermediate frequency amplifier and the second intermediate frequency amplifier to form an automatic gain control loop. The low noise amplifier inputs the first reference potential Vref1, the first intermediate frequency amplifier inputs the second reference potential Vref2, and the second intermediate frequency amplifier inputs the third reference potential Vref 3. Segment control of the gain at different received signal amplitudes is achieved by setting the first reference potential Vref1, the second reference potential Vref2, and the third reference potential Vref3.

The first reference potential Vref1, the second reference potential Vref2, and the third reference potential Vref3 may be provided by a voltage reference circuit of the ASK/OOK radio frequency receiving circuit, or may be generated by an external circuit.

The low noise amplifier is adjustable only when the control signal Vagc is near the first reference potential Vref1, and the gain value of the low noise amplifier is adjustable between its maximum limit and the minimum defined gain; the first stage intermediate frequency amplifier is only the control signal When Vagc is near the second reference potential Vref2, the gain value of the primary IF amplifier is adjustable between its maximum limit and the minimum defined gain; the secondary IF amplifier only when the control signal Vagc is near the third reference potential Vref3 The gain value of the secondary IF amplifier is adjustable between its maximum and minimum defined gains.

The capacitor is charged and discharged by a charge pump, and the ratio of the charging current to the discharging current of the charge pump is 1:n, and the value of n is determined by system characteristics: if the ASK/OOK radio frequency receiving circuit is set to be larger than the control signal Vagc, The greater the gain, the discharge current of the charge pump is greater than the charging current, and n is a positive number much greater than 1; if the ASK/OOK RF receiving circuit is set to have a larger control signal Vagc, the smaller the gain, the charge pump The discharge current should be less than the charge current, and n is a positive number much less than one.

The two input ends of the comparator respectively input a fourth reference potential Vref4 and a peak detection output, and the two outputs of the comparator are respectively connected to a charging current source and a discharging current source of the charge pump, one end of the capacitor is connected Between the charging current source and the discharging current source, the other end of the capacitor is grounded.

If the ASK/OOK radio frequency receiving circuit is expected to have a larger gain when the control signal Vagc is larger, the peak detection output is compared with the fourth reference potential Vref4, and the peak detection outputs a square wave composed of high and low potentials: 1) When the signal received by the antenna is small or the gain of the ASK/OOK radio frequency receiving circuit is insufficient, the peak detection output high and low potentials are lower than the fourth reference potential Vref4, and the comparator outputs charging control logic (0 or 1) to the electric charge. The pump and the charge pump continuously charge the capacitor, and the control signal Vagc rises, thereby increasing the gain value of the ASK/OOK RF receiving circuit until the detection output high potential is near the fourth reference potential Vref4; (2) when the antenna receives a large signal or ASK /OOK RF receiving circuit gain is too large, the high potential of the peak detection output is higher than the fourth reference potential Vref4, the low potential is lower than the fourth reference potential Vref4, and the comparator outputs a square wave similar to the signal before the ASK/OOK modulation, The charge pump alternately charges and discharges the capacitor. Since the discharge pump discharge current is much larger than the charging current, the overall effect of the charge pump is as a capacitor discharge, and the control signal Vagc is decreased, thereby reducing the gain value of the ASK/OOK RF receiving circuit until the detection output high potential is at the fourth reference potential Vref4. (3) When there is interference in the signal received by the antenna, and the gain of the ASK/OOK RF receiving circuit is too large, the peak detection output high and low potential are higher than the fourth reference potential Vref4, and the comparator output discharge control logic (1 or 0) gives the charge. The pump and the charge pump continuously discharge the capacitor, and the control signal Vagc will decrease, thereby reducing the gain value of the ASK/OOK RF receiving circuit until the detection output peak falls to the fourth reference potential Vref4, and the interference signal is reduced to Low position.

If the ASK/OOK radio frequency receiving circuit is expected to have a smaller gain when the control signal Vagc is larger, the peak detection output is compared with the fourth reference potential Vref4, and the peak detection outputs a square wave composed of high and low potentials: 1) When the signal received by the antenna is small or the gain of the ASK/OOK radio frequency receiving circuit is insufficient, the peak detection output high and low potentials are lower than the fourth reference potential Vref4, and the comparator outputs the discharge control logic (0 or 1) to the electric charge. The pump and the charge pump continuously discharge the capacitor, and the control signal Vagc decreases, thereby reducing the gain value of the ASK/OOK RF receiving circuit until the detection output high potential is near the fourth reference potential Vref4; (2) when the signal received by the antenna is large or The gain of the ASK/OOK radio frequency receiving circuit is too large, the high potential of the peak detection output is higher than the fourth reference potential Vref4, the low potential is lower than the fourth reference potential Vref4, and the comparator outputs a square wave similar to the signal before the ASK/OOK modulation. The charge pump alternately charges and discharges the capacitor. Since the charge pump charging current is much larger than the discharge current, the overall effect of the charge pump is represented by capacitive charging, and the control signal Vagc rises, thereby increasing the gain value of the ASK/OOK RF receiving circuit until the detection output high potential is at the fourth reference potential Vref4. (3) When there is interference in the signal received by the antenna, and the gain of the ASK/OOK RF receiving circuit is too large, the peak detection output high and low potential are higher than the fourth reference potential Vref4, and the comparator output charging control logic (1 or 0) gives the charge. The pump and the charge pump continuously charge the capacitor, and the control signal Vagc will rise, thereby increasing the gain value of the ASK/OOK RF receiving circuit until the detection output peak falls to the fourth reference potential Vref4, and the interference signal is reduced to a lower level. position.

The low noise amplifier, the first intermediate frequency amplifier, and the second intermediate frequency amplifier gain adjustment sequence are implemented by setting a first reference potential Vref1, a second reference potential Vref2 and a third reference potential Vref3, and each amplifier provides an ASK/ In addition to the gain required by the OOK RF receiving circuit, the preamplifier also reduces the noise of the respective rear stage circuits. When the signal received by the antenna changes from small to large, if the gain of the low noise amplifier or the first intermediate frequency amplifier is first adjusted. While maintaining the gain of the secondary IF amplifier unchanged, the noise ratio of the circuit output may not be guaranteed, and the sensitivity of the ASK/OOK RF receiving circuit is reduced. Therefore, the gain adjustment order is: when the signal received by the antenna increases from small to large, the gain of the secondary IF amplifier is adjusted first, then the gain of the primary IF amplifier is adjusted, and finally the gain of the low noise amplifier is adjusted. If the ASK/OOK RF receiving circuit is expected to have a larger gain when the control signal Vagc is larger, the first reference potential Vref1 < the second reference potential Vref2 < the third reference potential Vref3; if the ASK/OOK RF receiving circuit is desired to be controlled The larger the signal Vagc is, the smaller the gain is, and the first reference potential Vref1>the second reference potential Vref2>the third reference potential Vref3.

The gain adjustment ranges of the low noise amplifier, the first intermediate frequency amplifier and the second intermediate frequency amplifier may not overlap each other, that is, only the gain of one of the amplifiers is adjusted at the same time, and the other two gains are constant, and may overlap each other. This allows the gain of two or three amplifiers to be adjusted simultaneously, depending on the needs of the application.

The invention solves the blocking problem in the short-distance remote control, improves the dynamic range of the ASK/OOK radio frequency receiving circuit without affecting the sensitivity, and ASK/OOK radio frequency when a large one and a small two co-frequency signal sources exist simultaneously The receiving circuit will reduce the gain value according to the maximum signal, and finally drown the smaller signal in the noise floor. The ASK/OOK RF receiving circuit will correctly decode according to the maximum signal, and has the advantage of strong anti-interference ability. At the same time, the structure of the invention is simple, and the gain adjustment order and range of the low noise amplifier and the two-stage intermediate frequency amplifier can be adjusted by adjusting the values of the three reference voltages. Compared to other gain control methods, only a small wafer area and power consumption are required.

The content of the present invention will be further described below with reference to the accompanying drawings.

The ASK/OOK RF receiving circuit, as shown in Figure 4, includes: a low noise amplifier (41), an oscillator (50), a mixer (42), a primary IF amplifier (43), and a mid-band pass filter ( 44), a secondary intermediate frequency amplifier (45), a peak detection module (46), a comparator (47), a charge pump (48), a capacitor, and the low noise amplifier (41) amplifies a signal received by the antenna Then, together with the local oscillator generated by the oscillator (50), the mixer (42) is input, and the mixer (42) reduces the frequency of the output of the low noise amplifier (41) to the intermediate frequency, and the mixer ( 42) The output intermediate frequency signal is further amplified by a first-stage intermediate frequency amplifier (43), a medium-frequency pass filter (44), and a secondary intermediate frequency amplifier (45), and then demodulated and outputted by a peak detection module (46). The peak detection output is compared with the fourth reference potential Vref4 to drive the charge pump (48), and the charge pump (48) charges and discharges the capacitor to obtain a gain control signal Vagc, and the gain control signal Vagc is fed back to the low impurity Amplifier (41), a primary IF amplifier (43) and a secondary IF amplifier (45) form an automatic gain control loop, the low noise amplifier (41) input The first reference potential Vref1, the first intermediate frequency amplifier (43) inputs the second reference potential Vref2, and the second intermediate frequency amplifier (45) inputs the third reference potential Vref3, by the first reference potential Vref1, the second reference potential VVref2 and the The setting of the three reference potentials Vref3 enables segmentation control of the gain at different received signal amplitudes.

The first reference potential Vref1, the second reference potential Vref2, and the third reference potential Vref3 may be provided by a voltage reference circuit (49) of the ASK/OOK radio frequency receiving circuit, or may be generated by an external circuit.

The low noise amplifier (41) is adjustable between a maximum limit and a minimum defined gain of the low noise amplifier (41) only when the control signal Vagc is near the first reference potential Vref1; The frequency amplifier (43) is adjustable between a maximum limit and a minimum defined gain of the first stage intermediate frequency amplifier (43) only when the control signal Vagc is near the second reference potential Vref2; the secondary intermediate frequency amplifier ( 45) The gain value of the secondary IF amplifier (45) is adjustable between its maximum and minimum defined gains only when the control signal Vagc is near the third reference potential Vref3.

The ratio of the charging current to the discharging current of the charge pump (48) is 1:n, and the value of n is determined by the system characteristics: if the ASK/OOK radio frequency receiving circuit is set to have a larger control signal Vagc, the greater the gain, the The discharge current of the charge pump (48) is greater than the charging current, and n is a positive number much greater than 1; if the ASK/OOK RF receiving circuit is set to have a larger control signal Vagc, the smaller the gain, the charge pump (48) The discharge current should be less than the charge current and n is a positive number much less than one.

As shown in FIG. 6, the two input terminals of the comparator (47) respectively input a fourth reference potential Vref4 and a peak detection output, and two outputs of the comparator (47) are respectively connected to the charge pump (48). A charging current source and a discharging current source, one end of the capacitor being connected between the charging current source and the discharging current source, and the other end of the capacitor being grounded.

If the ASK/OOK radio frequency receiving circuit is expected to have a larger gain when the control signal Vagc is larger, the peak detection output is compared with the fourth reference potential Vref4, as shown in FIG. 7, the peak detection output is high and low. The square wave is composed of: (1) when the signal received by the antenna is small or the gain of the ASK/OOK radio frequency receiving circuit is insufficient, the peak detection output high and low potential are lower than the fourth reference potential Vref4, and the comparator outputs charging control logic ( 0 or 1) to the charge pump (48), the charge pump (48) continuously charges the capacitor, and the control signal Vagc rises, thereby increasing the gain value of the ASK/OOK RF receiving circuit until the detection output high potential is near the fourth reference potential Vref4 (2) When the signal received by the antenna is large or the gain of the ASK/OOK radio frequency receiving circuit is too large, the high potential of the peak detection output is higher than the fourth reference potential Vref4, and the low potential is lower than the fourth reference potential Vref4, the comparator (47) A square wave similar to the signal before ASK/OOK modulation is output, and the charge pump (48) alternately charges and discharges the capacitor. Since the discharge pump discharge current is much larger than the charging current, the overall effect of the charge pump is as a capacitor discharge, and the control signal Vagc is decreased, thereby reducing the gain value of the ASK/OOK RF receiving circuit until the detection output high potential is at the fourth reference potential Vref4. (3) When there is interference in the signal received by the antenna, and the gain of the ASK/OOK RF receiving circuit is too large, the peak detection output high and low potential are higher than the fourth reference potential Vref4, and the comparator (47) outputs the discharge control logic (1 or 0). To the charge pump (48), the charge pump (48) continuously discharges the capacitor, and the control signal Vagc will decrease, thereby reducing the gain value of the ASK/OOK RF receiving circuit until the detection output peak falls to the fourth reference potential Vref4. The interference signal is reduced to a lower position.

If the ASK/OOK radio frequency receiving circuit is expected to have a larger gain when the control signal Vagc is larger, the peak detection output is compared with the fourth reference potential Vref4, as shown in FIG. 7, the peak detection output is high and low. The square wave is composed of: (1) when the signal received by the antenna is small or the gain of the ASK/OOK radio frequency receiving circuit is insufficient, the peak detection output high and low potential are lower than the fourth reference potential Vref4, and the comparator (47) outputs the discharge. The control logic (0 or 1) is applied to the charge pump (48), the charge pump (48) is continuously discharged, and the control signal Vagc is decreased, thereby reducing the gain value of the ASK/OOK RF receiving circuit until the detection output is high. (2) when the signal received by the antenna is large or the gain of the ASK/OOK radio frequency receiving circuit is too large, the high potential of the peak detection output is higher than the fourth reference potential Vref4, and the low potential is lower than the fourth reference potential Vref4, The comparator (47) outputs a square wave similar to that before the ASK/OOK modulation, and the charge pump (48) alternately charges and discharges the capacitance. Since the charge pump (48) charging current is much larger than the discharge current, the overall effect of the charge pump (48) is represented by capacitive charging, and the control signal Vagc rises, thereby increasing the gain value of the ASK/OOK RF receiving circuit until the detection output is high. In the vicinity of the fourth reference potential Vref4; (3) when there is interference in the signal received by the antenna, and the gain of the ASK/OOK radio frequency receiving circuit is too large, the peak detection output high and low potential are higher than the fourth reference potential Vref4, and the comparator (47) outputs charging. The control logic (1 or 0) is applied to the charge pump (48), the charge pump (48) continuously charges the capacitor, and the control signal Vagc will rise, thereby increasing the gain value of the ASK/OOK RF receiving circuit until the detection output peak falls to the fourth Near the reference potential Vref4, the interference signal is reduced to a lower position.

The low noise amplifier, the first intermediate frequency amplifier, and the second intermediate frequency amplifier gain adjustment sequence are implemented by setting a first reference potential Vref1, a second reference potential Vref2 and a third reference potential Vref3, and each amplifier provides an ASK/ In addition to the gain required by the OOK RF receiving circuit, the preamplifier also reduces the noise of the respective rear stage circuits. When the signal received by the antenna changes from small to large, if the gain of the low noise amplifier or the first intermediate frequency amplifier is first adjusted. While maintaining the gain of the secondary IF amplifier unchanged, the noise ratio of the circuit output may not be guaranteed, and the sensitivity of the ASK/OOK RF receiving circuit is reduced. Therefore, the gain adjustment order is: when the signal received by the antenna increases from small to large, the gain of the secondary IF amplifier is adjusted first, then the gain of the primary IF amplifier is adjusted, and finally the gain of the low noise amplifier is adjusted. If the ASK/OOK RF receiving circuit is expected to have a larger gain when the control signal Vagc is larger, the first reference potential Vref1 < the second reference potential Vref2 < the third reference potential Vref3; if the ASK/OOK RF receiving circuit is desired to be controlled The larger the signal Vagc is, the smaller the gain is, and the first reference potential Vref1>the second reference potential Vref2>the third reference potential Vref3.

The gain adjustment range of the low noise amplifier (41), the first intermediate frequency amplifier (43) and the second intermediate frequency amplifier (45) may not overlap each other, that is, only the gain of one of the amplifiers is adjusted at the same time, and the other two The gains are constant and can overlap each other, allowing the gain of two or three amplifiers to be adjusted simultaneously, depending on the low noise amplifier, the first intermediate frequency amplifier (43) and the secondary intermediate frequency amplifier in the ASK/OOK RF receiving circuit. (45) Gain and dynamic range of each circuit in the ASK/OOK RF receive circuit.

For convenience of explanation, FIG. 5 shows that only the gains of one of the low noise amplifier (41), the first intermediate frequency amplifier (43) and the second intermediate frequency amplifier (45) are adjusted at the same time while the other two gains are unchanged. Assume that the larger the control signal Vagc is, the larger the gain is. It can be seen that when the signal received by the antenna is small and is within the first signal range shown, the control signal Vagc will change near the third reference potential Vref3, and the adjustment 2 The gain of the IF amplifier (45); when the signal received by the antenna reaches a medium size within the second signal range shown, the control signal Vagc will change near the second reference potential Vref2, adjusting the primary IF amplifier (43) Gain; when the signal received by the antenna is large and is in the third signal range shown, the control signal Vagc changes around the first reference potential Vref1 to adjust the gain of the low noise amplifier (41).

Similarly, if it is allowed to simultaneously adjust the gain of two or three amplifiers in the low noise amplifier (41), the primary IF amplifier (43) and the secondary IF amplifier (45), the signal received by the antenna can be divided. Five ranges from small to large: adjust the gain of the secondary IF amplifier (45) when the signal received by the antenna is in the first and second signal ranges; when the signal received by the antenna is in the second, third and fourth signal ranges Adjust the gain of the primary IF amplifier (43); adjust the gain of the low noise amplifier (41) when the signal received by the antenna is in the fourth and fifth signal ranges. Of course, there are many other ways of overlapping, which can be designed as needed.

The present invention discloses an ASK/OOK radio frequency receiving circuit, and describes specific embodiments and effects of the present invention with reference to the accompanying drawings. It should be understood that the above-described embodiments are merely illustrative of the invention, and are not intended to limit the invention, any inventions that are within the scope of the spirit of the invention, including but not limited to changes to the partial construction of the circuit, Replacement of the type or model, as well as other non-substantial replacements or modifications, are within the scope of the invention.

11, 21, 31, 41. . . Low noise amplifier

12, 22, 32, 42. . . Mixer

13, 23, 33, 43. . . Primary IF amplifier

14, 24, 34, 44. . . Bandpass filter

15, 25, 35, 45. . . Secondary IF amplifier

16, 36, 46. . . Peak detection module

26. . . Analog digital converter

27. . . Digital logic circuit

37. . . Gain controller

47. . . Comparators

48. . . Charge pump

49. . . Voltage reference circuit

17, 28, 38, 50. . . Oscillator

Figure 1 is a schematic diagram of a conventional ASK/OOK superheterodyne RF receiving circuit.

Figure 2 is a schematic diagram of an ASK/OOK superheterodyne RF receiving circuit with a digital automatic gain control loop.

FIG. 3 is a schematic diagram of an ASK/OOK superheterodyne RF receiving circuit of a conventional analog automatic gain control loop.

4 is a schematic diagram of an ASK/OOK radio frequency receiving circuit of the present invention.

Fig. 5 is a graph showing the gain-control voltage of the ASK/OOK radio frequency receiving circuit of the present invention.

Figure 6 is a schematic diagram of a comparator and a charge pump of the ASK/OOK radio frequency receiving circuit of the present invention.

FIG. 7 is a schematic diagram showing a comparison of a control signal Vagc and a fourth reference potential of the ASK/OOK radio frequency receiving circuit of the present invention.

41. . . Low noise amplifier

42. . . Mixer

43. . . Primary IF amplifier

44. . . Mid-band pass filter

45. . . Secondary IF amplifier

46. . . Peak detection module

47. . . Comparators

48. . . Charge pump

49. . . Voltage reference circuit

50. . . Oscillator

Claims (7)

An amplitude shift modulation/binary amplitude keying (ASK/OOK) radio frequency receiving circuit, comprising: a low noise amplifier, an oscillator, a mixer, a first intermediate frequency amplifier, a medium frequency band pass filter, and a second stage An intermediate frequency amplifier, a peak detection module, a comparator, a charge pump, and a capacitor, wherein the low noise amplifier amplifies the signal received by the antenna and inputs the mixer together with the local oscillator generated by the oscillator, the mixing The frequency of the output of the low noise amplifier is reduced to the intermediate frequency, and the intermediate frequency signal output by the mixer is amplified by the first intermediate frequency amplifier, filtered by the medium frequency band filter, and amplified by the second intermediate frequency amplifier, and then solved by the peak detection module. Adjusting the output, the peak detection output is compared with the fourth reference potential Vref4, charging and discharging the capacitor according to the output result of the comparator to obtain a gain control signal Vagc, and the gain control signal Vagc is fed back to the low noise amplifier, the first stage The frequency amplifier and the secondary intermediate frequency amplifier form an automatic gain control loop, the low noise amplifier inputs a first reference potential Vref1, and the first intermediate frequency amplifier inputs a second With reference to the potential Vref2, the secondary intermediate frequency amplifier inputs a third reference potential Vref3, and the segmentation control of the gain at different received signal amplitudes is achieved by setting the first reference potential Vref1, the second reference potential Vref2 and the third reference potential Vref3. The ASK/OOK radio frequency receiving circuit according to claim 1, wherein the low noise amplifier has a gain value of a low noise amplifier at a maximum limit and a minimum when the control signal Vagc is near the first reference potential Vref1. Adjustable between gains; the primary IF amplifier is only a control letter When the Vagc is near the second reference potential Vref2, the gain value of the primary IF amplifier is adjustable between its maximum limit and the minimum defined gain; the secondary IF amplifier is only when the control signal Vagc is near the third reference potential Vref3 The gain value of the secondary IF amplifier is adjustable between its maximum and minimum defined gains. The ASK/OOK radio frequency receiving circuit according to claim 1, wherein the capacitor is charged and discharged by a charge pump, and the ratio of the charging current to the discharging current of the charge pump is 1:n, and the value of n is determined by system characteristics. Decide: If the ASK/OOK RF receiving circuit is expected to be set to a larger control signal Vagc, the greater the gain, the discharge current of the charge pump is greater than the charging current, n is a positive number much greater than 1; if ASK/OOK RF is desired When the receiving circuit is set to have a larger control signal Vagc, the smaller the gain, the discharge current of the charge pump should be smaller than the charging current, and n is a positive number much smaller than 1. The ASK/OOK radio frequency receiving circuit according to claim 1, wherein the two input ends of the comparator respectively input a fourth reference potential Vref4 and a peak detection output, and the two outputs of the comparator respectively connect the electric charges. A charging current source and a discharging current source of the pump, one end of the capacitor being connected between the charging current source and the discharging current source, and the other end of the capacitor being grounded. The ASK/OOK radio frequency receiving circuit as claimed in claim 1, wherein the low noise amplifier, the first intermediate frequency amplifier, and the second intermediate frequency amplification The order of the gain adjustment is implemented by setting the first reference potential Vref1, the second reference potential Vref2 and the third reference potential Vref3. If the ASK/OOK RF receiving circuit is expected to have a larger gain, the first gain is The reference potential Vref1<the second reference potential Vref2<the third reference potential Vref3; if the ASK/OOK radio frequency receiving circuit is expected to have a larger gain when the control signal Vagc is smaller, the first reference potential Vref1>the second reference potential Vref2> The third reference potential Vref3. The ASK/OOK radio frequency receiving circuit according to claim 1, 2, 3, 4 or 5, wherein if the ASK/OOK radio frequency receiving circuit is expected to have a larger gain when the control signal Vagc is larger, the peak value is obtained. The detection output is compared with the fourth reference potential Vref4, and the peak detection outputs a square wave composed of high and low potentials; (1) when the signal received by the antenna is small or the gain of the ASK/OOK radio frequency receiving circuit is insufficient, the peak detection output is high or low. The potential is lower than the fourth reference potential Vref4, the comparator outputs charging control logic (0 or 1) to the charge pump, the charge pump continuously charges the capacitor, and the control signal Vagc rises, thereby increasing the gain value of the ASK/OOK RF receiving circuit. Until the detection output high potential is near the fourth reference potential Vref4; (2) when the signal received by the antenna is large or the gain of the ASK/OOK radio frequency receiving circuit is too large, the high potential of the peak detection output is higher than the fourth reference potential Vref4, low The potential is lower than the fourth reference potential Vref4, the comparator outputs a square wave similar to the signal before the ASK/OOK modulation, and the charge pump alternately charges and discharges the capacitor, since the charge pump discharge current is much larger than the charge Current, the overall effect of the charge pump capacitor discharge performance, decrease the control signal Vagc, Thereby reducing the gain value of the ASK/OOK RF receiving circuit until the detection output high potential is near the fourth reference potential Vref4; (3) when the signal received by the antenna has interference, and the ASK/OOK RF receiving circuit gain is too large, the peak detection output is high or low The potential is higher than the fourth reference potential Vref4, the comparator outputs discharge control logic (1 or 0) to the charge pump, the charge pump continuously discharges the capacitor, and the control signal Vagc is reduced, thereby reducing the gain of the ASK/OOK RF receiving circuit. The value is reduced until the detection output peak falls near the fourth reference potential Vref4, and the interference signal is reduced to a lower position. The ASK/OOK radio frequency receiving circuit as claimed in claim 1, 2, 3, 4 or 5, wherein if the ASK/OOK radio frequency receiving circuit is expected to have a larger gain when the control signal Vagc is larger, the peak value is obtained. The detection output is compared with the fourth reference potential Vref4, and the peak detection outputs a square wave composed of high and low potentials; (1) when the signal received by the antenna is small or the gain of the ASK/OOK radio frequency receiving circuit is insufficient, the peak detection output is high or low. The potential is lower than the fourth reference potential Vref4, the comparator outputs discharge control logic (0 or 1) to the charge pump, the charge pump continuously discharges the capacitor, and the control signal Vagc decreases, thereby reducing the gain of the ASK/OOK RF receiving circuit. The value until the detection output high potential is near the fourth reference potential Vref4; (2) when the signal received by the antenna is large or the gain of the ASK/OOK radio frequency receiving circuit is too large, the high potential of the peak detection output is higher than the fourth reference potential Vref4, The low potential is lower than the fourth reference potential Vref4, the comparator outputs a square wave similar to the signal before the ASK/OOK modulation, and the charge pump alternately charges and discharges the capacitor, since the charge pump charging current is much larger than the discharge current Current, the overall effect of the charge pump capacitor charging performance, increased control signal Vagc, Thereby increasing the gain value of the ASK/OOK RF receiving circuit until the detection output high potential is near the fourth reference potential Vref4; (3) when the signal received by the antenna has interference, and the ASK/OOK RF receiving circuit gain is too large, the peak detection output is high or low The potential is higher than the fourth reference potential Vref4, the comparator outputs charging control logic (1 or 0) to the charge pump, the charge pump continuously charges the capacitor, and the control signal Vagc will rise, thereby increasing the gain value of the ASK/OOK RF receiving circuit. Until the detection output peak falls near the fourth reference potential Vref4, the interference signal is reduced to a lower position.