Device for expanding linear measurement range of signal intensity

Abstract

The utility model provides a device for expanding the linear measurement range of signal intensity, which comprises a resistance attenuation network, a low-noise amplifier U51, a bypass straight-through circuit, a radio frequency switch U4 and a radio frequency switch U5, the resistance attenuation network is connected between the radio frequency switch U4 and the radio frequency switch U5, and the low-noise amplifier U51, the bypass straight-through circuit and the resistance attenuation network are connected between the radio frequency switch U4 and the radio frequency switch U5. The low-noise amplifier U51 and the bypass straight-through circuit are connected in parallel, and the radio frequency switches U4 and U5 are both connected with the MCU control circuit; the device controls the radio frequency switches U4 and U5 to dynamically switch the resistance attenuation network, the low-noise amplifier U51 and the bypass straight-through circuit through the MCU control circuit according to the numerical value of the signal intensity, so that the linear measurement range of an accessed chip is larger, the device can adapt to more application scenes, and the device can be compatible with different chips and has high practicability. The implementation cost is low, software algorithm modification is small, and rapid implementation is facilitated.

Description

TECHNICAL FIELD

[0001] The technical field of the utility model belongs to wireless communication technology field, especially relate to a device of expanding signal strength linear measurement range. BACKGROUND

[0002] Commonly used receiver uses ADC method to measure the strength of radio frequency signal, converts into RSSI reading value and returns to user. In actual use, it is found that the linear range of RSSI reading value of receiver is not very large, and the RSSI reading value of industrial grade chip is between-40dBm / MHz to-85dBm / MHz. When the signal is more than-40dBm, it will be saturated, and when the signal is less than-85dBm, it will be in nonlinear region, and the RSSI reading value will have uncertain deviation in saturation area and nonlinear area. When the chip receives the signal with strength less than-85dBm, the RSSI reading value of the chip will be larger than the actual signal strength. When the chip receives the signal with strength higher than-40dBm, the RSSI reading value of the chip will be smaller than the actual signal strength.

[0003] And the reading value in the nonlinear region can only be solved by production calibration without changing the circuit in the prior art. But production calibration will increase the production cost.

[0004] For example, the super large dynamic high performance receiver system is disclosed in China patent network, and the application number is 202410926205.6. In the patent, the signal receiving module, the adaptive gain control module, the signal processing module, the digital pre-distortion compensation module and the intelligent signal detection and separation module are arranged to expand the measurement range of the signal. Thus, the modules involved are more, the production cost is higher, and the maintenance is not easy. UTILITY MODEL CONTENT

[0005] The utility model aims at reducing the implementation cost under the premise of ensuring the expansion of the RSSI reading value range of the receiver chip, and will not replace the existing chip, the software algorithm is changed less, and it is beneficial to rapid implementation.

[0006] In order to realize the above purpose, the utility model adopts the following technical scheme:

[0007] The designed device comprises: radio frequency switch U4 and U5, low noise amplifier U51 and resistance attenuation network, the low noise amplifier U51 and the resistance attenuation network are connected between the radio frequency switch U4 and U5, and the radio frequency switch U4 and U5 are connected with MCU control circuit.

[0008] Preferably, the connection mode of the resistance attenuation network is as follows: the third pin of the RF switch U5 is connected to the first impedance; the first end of the resistor R29 is connected to the first impedance, and the second end of the resistor R29 is grounded; the first end of the resistor R29 and the first end of the first impedance are connected to the second end of the resistor R27; the first end of the resistor R27 is connected to the second end of the second impedance; the first end of the resistor R28 is connected to the second end of the second impedance, and the first end of the second impedance is connected to the 9th pin of the RF switch U4.

[0009] Preferably, the connection mode of the resistance attenuation network is as follows: the 9th pin of the RF switch U5 is connected to the third impedance; the first end of the resistor R26 is connected to the third impedance; the first end of the resistor R26 and the third impedance is connected to the second end of the resistor R24; the first end of the resistor R24 ​​and the second end of the fourth impedance are connected to the first end of the resistor R25; the first end of the resistor R25 is connected to the fourth impedance; and the first end of the fourth impedance is connected to the 3rd pin of the RF switch U4.

[0010] Preferably, the connection method of the low-noise amplifier U51 is: the second pin of the RF switch U5 is connected to the fifth impedance; the first end of the fifth impedance is connected to the second end of the capacitor C34, and the first end of the capacitor C34 is connected to the seventh pin of the low-noise amplifier U51; the second pin of the low-noise amplifier U51 is connected to the second end of the capacitor C31; the first end of the capacitor C31 is connected to the second end of the sixth impedance; and the first end of the sixth impedance is connected to the tenth pin of the RF switch U4.

[0011] Preferably, the 6th pin, the 5th pin and the 4th pin of the RF switch U5 are respectively connected to the second ends of the capacitor C26, the capacitor C27 and the capacitor C28; the first ends of the capacitor C26, the capacitor C27 and the capacitor C28 are all grounded.

[0012] Preferably, 6. Pin 4, pin 5 and pin 6 of the RF switch are connected to the first ends of capacitors C23, C24 and C25; and the second ends of capacitors C23, C24 and C25 are all grounded.

[0013] Preferably, the 13th pin of the RF switch U5 is connected to the first end of the seventh impedance; the first end of the capacitor C29 is connected to the seventh impedance; the first end of the resistor R22 is connected to the second end of the seventh impedance; the second end of the resistor R22 is connected to the first end of the eighth impedance; and the first end of the capacitor C30 is connected to the eighth impedance.

[0014] As preferred, the 13th pin of the radio frequency switch U4 is connected with the second end of the ninth impedance; the first end of the capacitor C22 is connected with the ninth impedance; the second end of the resistor R21 is connected with the first end of the ninth impedance; the first end of the resistor R21 is connected with the second end of the tenth impedance; the first end of the capacitor C21 is connected with the tenth impedance.

[0015] As preferred, the 10th pin of the radio frequency switch U5 is connected with the second end of the eleventh impedance; the 2nd pin of the radio frequency switch U4 is connected with the first end of the eleventh impedance.

[0016] The utility model discloses the beneficial effect lies in, enlargates the upper limit and lower limit of linear reading range on reading value linear reading value, realizes low cost, under the premise of not replacing the existing receiving chip, increases the SP4T radio frequency switch of GPIO control, attenuation resistance network, only LNA price is slightly expensive. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is the circuit diagram of the utility model.

[0018] Figure 2 It is the circuit frame diagram of the utility model.

[0019] Figure 3 It is linear reading value schematic diagram of a chip. DETAILED DESCRIPTION

[0020] In some embodiments, the utility model discloses the circuit connection mode of the utility model, as shown in Figure 1 .

[0021] The device related to the utility model includes: radio frequency switch U5, radio frequency switch U4, low noise amplifier U51, resistance attenuation network, bypass circuit.

[0022] The resistance attenuation network includes -20dBm resistance attenuation network and -40dBm resistance attenuation network.

[0023] The circuit connection mode of -20dBm resistance attenuation network is as follows: the 9th pin of radio frequency switch U5 is connected with the second end of the third impedance, the first end of resistance R26 is connected with the third impedance, and the second end of resistance R26 is grounded; the second end of resistance R24 is connected with the first end of the third impedance; the first end of resistance R24 is connected with the second end of the fourth impedance, and the first end of resistance R25 is connected with the fourth impedance; the first end of the fourth impedance is connected with the 3rd pin of radio frequency switch U4.

[0024] The circuit connection mode of the -40dBm resistance attenuation network is that the third pin of the radio frequency switch U5 is connected with the second end of the first impedance, the first end of the resistance R29 is connected with the first impedance, and the second end of the resistance R29 is grounded; the second end of the resistance R27 is connected with the second end of the first impedance; the first end of the resistance R27 is connected with the second end of the second impedance; the first end of the resistance R28 is connected with the second impedance, and the second end of the resistance R28 is grounded; the second impedance is connected with the ninth pin of the radio frequency switch U4.

[0025] The connection mode of the low noise amplifier U51 is that the second pin of the radio frequency switch U5 is connected with the first end of the fifth impedance, the first end of the fifth impedance is connected with the second end of the capacitor C34, and the first end of the capacitor C34 is connected with the seventh pin of the low noise amplifier U51; the second pin of the low noise amplifier U51 is connected with the second end of the capacitor C31; the first end of the capacitor C31 is connected with the second end of the sixth impedance; the first end of the sixth impedance is connected with the tenth pin of the radio frequency switch U4.

[0026] The connection mode of the bypass through circuit is that the second end of the eleventh impedance is connected with the tenth pin of the radio frequency switch U5, and the first end of the eleventh impedance is connected with the second pin of the radio frequency switch U4.

[0027] It should be additionally noted that the first end of the capacitor C34 and the seventh pin of the low noise amplifier U51 are both connected with the second end of the inductor L21; the first end of the inductor L21 is connected with the first end of the capacitor C33, the second end of the capacitor C33 is grounded; the first end of the capacitor C33 is connected with the second end of the capacitor C32, the second end of the capacitor C32 is connected with the first end of the resistance R23, the second end of the resistance R23 is connected with the first pin of the low noise amplifier U51; the first end of the capacitor C32 is grounded.

[0028] The thirteenth pin of the radio frequency switch U5 is connected with the first end of the seventh impedance, the first end of the capacitor C29 is connected with the seventh impedance, and the second end of the capacitor C29 is grounded; the second end of the seventh impedance is connected with the first end of the resistance R22, and the second end of the resistance R22 is connected with the first end of the eighth impedance; the first end of the capacitor C30 is connected with the eighth impedance, and the second end of the capacitor C30 is grounded.

[0029] The thirteenth pin of the radio frequency switch U4 is connected with the second end of the ninth impedance, the first end of the capacitor C22 is connected with the ninth impedance, and the second end of the capacitor C22 is grounded; the first end of the ninth impedance is connected with the second end of the resistance R21, and the first end of the resistance R22 is connected with the tenth impedance; the first end of the capacitor C21 is connected with the tenth impedance, and the second end of the capacitor C21 is grounded.

[0030] The sixth pin, the fifth pin and the fourth pin of the radio frequency switch U5 are connected with the second end of the capacitor C26, the second end of the capacitor C27 and the second end of the capacitor C28 respectively; the first end of the capacitor C26, the first end of the capacitor C27 and the first end of the capacitor C28 are grounded, and the capacitances of the capacitor C26, the capacitor C27 and the capacitor C28 are 100 pF.

[0031] The fifth pin, the sixth pin and the seventh pin of the radio frequency switch U4 are connected with the first pin of the capacitor C23, the first pin of the capacitor C24 and the first pin of the capacitor C25 respectively; the second end of the capacitor C23, the second end of the capacitor C24 and the second end of the capacitor C25 are grounded, and the capacitances of the capacitor C23, the capacitor C24 and the capacitor C25 are 100 pF.

[0032] It needs to be explained that if the radio frequency switch U5 and the radio frequency switch U4 are switched to the bypass straight-through circuit, if the whole device receives a certain signal, the signal strength of the device outputting the signal remains unchanged.

[0033] If the radio frequency switch U5 and the radio frequency switch U4 are switched to the -20dBm resistance attenuation network, if the whole device receives a certain signal, the strength of the signal output by the device is reduced by 20dBm.

[0034] If the radio frequency switch U5 and the radio frequency switch U4 are switched to the -40dBm resistance attenuation network, if the whole device receives a certain signal, the strength of the signal output by the device is reduced by 40dBm.

[0035] If the radio frequency switch U5 and the radio frequency switch U4 are switched to the +20dBm low-noise amplifier, if the whole device receives a certain signal, the strength of the signal output by the device is increased by 20dBm.

[0036] Similarly, different performance resistance attenuation networks and different performance low-noise amplifiers can also be replaced according to actual measurement needs.

[0037] In some embodiments, the present embodiment discloses how the device works according to the strength of the signal, as shown in the figure. Figure 2 The frame diagram of the device.

[0038] If it is necessary to expand the signal detection range of a certain chip, the linear reading range of the chip is -40dBm to -80dBm. The reading value of the chip is as shown in the figure. Figure 3 When the chip receives a signal with a strength less than -80dBm, the reading value of the chip for the signal strength will be large, that is, the RSSI reading value is small; when the chip receives a signal with a strength greater than -20dBm, the reading value of the chip for the signal will be small, that is, the RSSI reading value is small.

[0039] The chip is connected to the output of the embodiment, the device starts to receive signals, first through the MCU control circuit to switch the radio frequency switch U5 and the radio frequency switch U4 to the bypass circuit, if the RSSI reading value of the chip is between -80dBm and -40dBm, then directly take the value as the measured value of the signal, because the chip is linear reading between -80dBm and -40dBm, the difference between the read signal strength and the actual signal strength is small.

[0040] If the RSSI reading value of the chip is less than -80dBm, then through the MCU control circuit to switch the radio frequency switch U5 and the radio frequency switch U4 to the low noise amplifier, the signal strength of the device will increase 20dBm after passing through the low noise amplifier, which will be illustrated by an example below.

[0041] For example: a signal with a signal strength of -85dBm is received by the device, the chip reads the signal strength less than -80dBm, at this time, through the MCU control circuit to switch the radio frequency switch U5 and the radio frequency switch U4 to the low noise amplifier, the signal strength increases 20dBm after passing through, and the RSSI value is -65dBm, which is within the linear reading range of the chip, at this time, to know the actual strength of the signal, only need to subtract -20dBm from the read RSSI value, and the actual signal strength of the signal is obtained.

[0042] If the RSSI reading value of the chip is greater than -40dBm and less than -20dBm, then through the MCU control circuit to switch the radio frequency switch U5 and the radio frequency switch U4 to the -20dBm resistance attenuation network, which will be illustrated by an example below.

[0043] For example: a signal with a signal strength of -34dBm is received by the device, the chip reads the signal strength greater than -40dBm, at this time, through the MCU control circuit to switch the radio frequency switch U5 and the radio frequency switch U4 to the -20dBm resistance attenuation network, the signal strength decreases 20dBm after passing through, and the RSSI value is -54dBm, which is within the linear reading range of the chip, at this time, to know the actual strength of the signal, only need to add 20dBm to the read RSSI value, and the actual signal strength of the signal is obtained.

[0044] If the RSSI reading value of the chip is greater than or equal to -20dBm, then through the MCU control circuit to switch the radio frequency switch U5 and the radio frequency switch U4 to the -40dBm resistance attenuation network, which will be illustrated by an example below.

[0045] For example, if a signal with a signal strength of -15dBm is received by the device, and the chip reads a signal strength greater than -40dBm, the MCU control circuit will switch the RF switch U5 and the RF switch U4 to the -40dBm resistance attenuation network at this time, and when this signal passes through, the signal strength decreases by 40dBm, and the RSSI value is -55dBm, which is within the linear reading range of the chip. At this time, to know the actual strength of the signal, only need to add 40dBm to the RSSI value read to obtain the actual signal strength of the signal.

[0046] Through the device, the chip originally only has a linear measurement range of -80dBm to -40dBm is significantly expanded to a linear measurement range of -100dBm to 0dBm. This expansion not only improves the detection ability of the chip for lower signal strength, but also enhances its adaptability and flexibility in various application scenarios, so that the chip can accurately measure in a wider signal environment.

[0047] The linear measurement range of a certain chip can also be further expanded in a series manner. Specifically, by connecting multiple devices mentioned in the above embodiments in series, wider measurement capability can be achieved.

[0048] In some embodiments, the present embodiment discloses how to further expand the linear measurement range of the chip by connecting the devices involved in the present application in series.

[0049] If the linear measurement range of a certain chip is -85dBm to -22dBm, two devices involved in the previous embodiment are selected, and for convenience of the following description, they are denoted as device A and device B.

[0050] The output end of device A is connected to the input end of device B, and the RF switch U4 and the RF switch U5 of device A and device B are connected to the MCU control circuit, and the output end of device B is connected to the chip.

[0051] If the receiving end of device A receives a signal with a signal strength of -110dBm, if only one of the devices is used for expansion at this time, that is, the RF switch is switched to the +20dBm low noise amplifier through the MCU control circuit, after amplification, the signal strength is -90dBm, which is not within the linear measurement range of the chip, so that the RSSI reading value of the chip deviates from the actual signal strength.

[0052] The signal through the device involved in this embodiment, the signal strength is less than -85dBm, at least to enhance 45dBm, to accurately obtain the actual signal strength of the signal, at this time the RF switch U5 and RF switch U4 in device A through MCU control circuit is switched to +20dBm low noise amplifier, RF switch U5 and RF switch U4 in device B through MCU control circuit is switched to +20dBm low noise amplifier, at this time, the output strength of the signal is -70dBm, in the linear reading value area of the chip, at this time, if you want to know the actual signal strength of the signal, only need to subtract 40dBm from the RSSI reading value of the chip.

[0053] If there is a signal through the device involved in this embodiment, the signal strength is greater than -22dBm, the actual strength of the signal is 20, if at this time if only one signal device is used for expansion, that is, through the MCU control circuit, the RF switch is switched to the -40dBm resistance attenuation network, after attenuation, the signal strength of the signal is -20dBm, not in the linear measurement range of the chip, so the RSSI reading value of the chip deviates from the actual signal strength of the signal.

[0054] Therefore, through the device involved in this embodiment, the RF switch U4 and RF switch U5 of device A are switched to the -40dBm resistance attenuation network through the MCU control circuit, and the RF switch U4 and RF switch U5 of device B are switched to the -20dBm resistance attenuation network through the MCU control circuit. After signal attenuation, the signal strength of the signal is -40dBm, which is in the linear measurement range of the chip, so to know the actual signal strength of the signal, only need to add 40dBm to the RSSI reading value of the chip to obtain the actual signal strength of the signal.

[0055] Through the device, the linear measurement range of the chip is significantly expanded from -85dBm to -22dBm to -125dBm to 58dBm. This expansion not only enables the chip to measure lower intensity signals, but also enables it to process higher intensity signals, greatly increasing its linear measurement range.

[0056] The utility model discloses through concrete embodiment in -depth explanation its purpose, technical scheme and beneficial effect, but these embodiments only as example, with show the application mode of invention, do not constitute the limit of the protection scope of the utility model. We explicitly point out, any reasonable modification, equivalent replacement or technical improvement under the guidance of the utility model spirit and principle should be included in the protection scope of the utility model. This means, as long as these changes do not deviate from the core idea and basic function of invention, they should be protected by patent right. The protection scope of the utility model should be extensive, including all direct obvious variants and the non-obvious innovation that can be reasonably deduced by technical experts according to the utility model disclosure. This broad protection aims to promote further research and development based on the utility model, while ensuring that its innovativeness and practicality are comprehensively legally protected.

Claims

1. A device for extending the linear measurement range of signal strength, characterized in that: The device includes: radio frequency switches U4 and U5, a low noise amplifier U51 and a resistor attenuation network, and a bypass circuit; The low noise amplifier U51, the resistance attenuation network and the bypass circuit are connected between the RF switch U4 and the RF switch U5; The bypass, the resistor attenuation network and the noise amplifier U51 are connected in parallel; The radio frequency switch U4 and the radio frequency switch U5 are connected to the MCU control circuit.

2. The device for extending the linear measurement range of signal strength according to claim 1, characterized in that: The connection method of the resistance attenuation network is as follows: the third pin of the RF switch U5 is connected to the first impedance; the first end of the resistor R29 is connected to the first impedance, and the second end of the resistor R29 is grounded; the first end of the resistor R29 and the first end of the first impedance are connected to the second end of the resistor R27; the first end of the resistor R27 is connected to the second end of the second impedance; the first end of the resistor R28 is connected to the second end of the second impedance, and the first end of the second impedance is connected to the 9th pin of the RF switch U4.

3. The device for extending the linear measurement range of signal strength according to claim 1, characterized in that: The connection method of the resistance attenuation network is as follows: the 9th pin of the RF switch U5 is connected to the third impedance; the first end of the resistor R26 is connected to the third impedance; the first end of the resistor R26 and the third impedance is connected to the second end of the resistor R24; the first end of the resistor R24 ​​and the second end of the fourth impedance are connected to the first end of the resistor R25; the first end of the resistor R25 is connected to the fourth impedance; and the first end of the fourth impedance is connected to the 3rd pin of the RF switch U4.

4. The device for extending the linear measurement range of signal strength according to claim 1, characterized in that: The connection method of the low-noise amplifier U51 is as follows: the second pin of the RF switch U5 is connected to the fifth impedance; the first end of the fifth impedance is connected to the second end of the capacitor C34, and the first end of the capacitor C34 is connected to the seventh pin of the low-noise amplifier U51; the second pin of the low-noise amplifier U51 is connected to the second end of the capacitor C31; the first end of the capacitor C31 is connected to the second end of the sixth impedance; and the first end of the sixth impedance is connected to the tenth pin of the RF switch U4.

5. The device for extending the linear measurement range of signal strength according to any one of claims 1 to 4, characterized in that: The 6th pin, the 5th pin and the 4th pin of the RF switch U5 are connected to the second ends of the capacitor C26, the capacitor C27 and the capacitor C28 respectively; the first ends of the capacitor C26, the capacitor C27 and the capacitor C28 are all grounded.

6. The device for extending the linear measurement range of signal strength according to any one of claims 1 to 4, characterized in that: Pin 4, pin 5 and pin 6 of the RF switch are connected to first ends of capacitors C23, C24 and C25; second ends of capacitors C23, C24 and C25 are grounded.

7. The device for extending the linear measurement range of signal strength according to any one of claims 1 to 4, characterized in that: Pin 13 of the RF switch U5 is connected to the first end of the seventh impedance; the first end of the capacitor C29 is connected to the seventh impedance; the first end of the resistor R22 is connected to the second end of the seventh impedance; the second end of the resistor R22 is connected to the first end of the eighth impedance; and the first end of the capacitor C30 is connected to the eighth impedance.

8. The device for extending the linear measurement range of signal strength according to any one of claims 1 to 4, characterized in that: The 13th pin of the RF switch U4 is connected to the second end of the ninth impedance; the first end of the capacitor C22 is connected to the ninth impedance; the second end of the resistor R21 is connected to the first end of the ninth impedance; the first end of the resistor R21 is connected to the second end of the tenth impedance; and the first end of the capacitor C21 is connected to the tenth impedance.

9. The device for extending the linear measurement range of signal strength according to any one of claims 1 to 4, characterized in that: The bypass circuit is connected in the following manner: the 10th pin of the RF switch U5 is connected to the second end of the eleventh impedance; The second pin of the RF switch U4 is connected to the first end of the eleventh impedance.

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