Radio frequency optical fiber transmission transmitter

Abstract

The utility model discloses a radio frequency optical fiber transmission transmitter which comprises a master control module, a transmitting end RF transmission link connected with the master control module and a laser module, an input end of the transmitting end RF transmission link is connected with an RF signal, an output end of the transmitting end RF transmission link is connected with the laser module, and the laser module is connected with the master control module. The laser module converts RF signals into optical signals and then outputs the optical signals, the pilot signal injection module, the logarithmic detector module and the diagnosis monitoring signal output module are connected with the master control module, the pilot signal injection module is further connected with the input end of the transmitting end RF transmission link, and the logarithmic detector module is further connected with the output end of the transmitting end RF transmission link. And the logarithmic detector module is also connected with the output end of the transmitting end RF transmission link. According to the utility model, the RF transmission link can be monitored and diagnosed, and maintenance personnel can conveniently maintain the RF link.

Description

Technical Field

[0001] The utility model relates to the technical field of communications, and particularly to a radio frequency over fiber transmitter. Background Art

[0002] RFOF (Radio Frequency over Fiber) is a technology and solution for transmitting radio frequency signals through optical fibers.

[0003] With the increasing demand for high-bandwidth and low-latency communications, RFOF devices are being increasingly widely used in fields such as telecommunications, cable television, and satellite communications, driving the continuous growth of the market scale. Currently, very few RFOF devices can be found on the domestic market, and high-performance RFOF products basically rely on imports.

[0004] Existing RFOF devices cannot monitor and diagnose RF transmission links, making it inconvenient for maintenance personnel to maintain RF links.

[0005] Therefore, the existing technology needs to be improved. Content of the Utility Model

[0006] In view of the deficiencies of the above-mentioned existing technology, the purpose of the utility model is to provide a radio frequency over fiber transmitter, aiming to be able to monitor and diagnose RF transmission links and facilitate the maintenance of RF links by maintenance personnel.

[0007] To achieve the above purpose, the utility model has taken the following technical solutions:

[0008] A radio frequency over fiber transmitter includes a main control module, a transmitting end RF transmission link and a laser module connected to the main control module. The input end of the transmitting end RF transmission link receives an RF signal, and the output end of the transmitting end RF transmission link is connected to the laser module. The laser module converts the RF signal into an optical signal and then outputs it, wherein:

[0009] It further includes a pilot signal injection module, a logarithmic detector module and a diagnostic monitoring signal output module connected to the main control module. The pilot signal injection module is also connected to the input end of the transmitting end RF transmission link, and the logarithmic detector module is also connected to the output end of the transmitting end RF transmission link.

[0010] In some examples, the transmitting - end RF transmission link includes an RF amplifier module and a digital - controlled attenuation module connected to the main control module. The input end of the RF amplifier module accesses the RF signal and the pilot - signal injection module. The output end of the RF amplifier module is connected to the input end of the digital - controlled attenuation module. The output end of the digital - controlled attenuation module is connected to the input end of the laser module and the logarithmic detector module.

[0011] In some examples, the pilot - signal injection module includes a first current - limiting resistor, a second current - limiting resistor, a triode array, and a first RF - signal transmission capacitor. The triode array includes a first triode and a second triode.

[0012] The input ends of the first current - limiting resistor and the second current - limiting resistor are both connected to the control signal input by the main control module. The output end of the first current - limiting resistor is connected to the base of the first triode. The output end of the second current - limiting resistor is connected to the base of the second triode. The emitter of the first triode is connected to the RF signal input by the main control module. The emitter of the second triode is grounded.

[0013] The collector of the first triode is connected to one end of the first RF - signal transmission capacitor. The other end of the RF - signal transmission capacitor is connected to the RF - signal output node. The collector of the second triode is connected to the RF - signal output node.

[0014] In some examples, the logarithmic detector module includes a logarithmic amplifier, a second RF - signal transmission capacitor, a third current - limiting resistor, and a voltage divider. The input end of the second RF - signal transmission capacitor is connected to the output end of the digital - controlled attenuation module. The output end of the second RF - signal transmission capacitor is connected to the input pin of the logarithmic amplifier. The output pin of the logarithmic amplifier is connected to the input end of the third current - limiting resistor. The output end of the third current - limiting resistor is connected to the main control module. The output pin of the logarithmic amplifier is also connected to the voltage divider.

[0015] In some examples, the laser module includes a laser and a laser - driving module. The input end of the laser is connected to the output end of the digital - controlled attenuation module. The output end of the laser emits an optical signal. The laser is also connected to the main control module and the laser - driving module.

[0016] In some examples, the laser - driving module includes a digital - to - analog converter, a precision operational amplifier, and a V / I conversion circuit connected in sequence. The digital - to - analog converter is also connected to the main control module. The V / I conversion circuit is also connected to the laser.

[0017] In some examples, the diagnostic - monitoring signal output module includes an LED indication module connected to the main control module and / or a diagnostic - monitoring signal interface connected to the main control module.

[0018] In some examples, a temperature compensation module connected to the main control module is further included.

[0019] In some examples, a power supply module is further included. The power supply module includes an adapter module, a negative output DC / DC conversion module, a boost module, a first voltage regulator module, a second voltage regulator module, and a low dropout linear regulator module.

[0020] The adapter module outputs a DC voltage to the input ends of the negative output DC / DC conversion module and the boost module. The output end of the boost module is connected to the input ends of the first voltage regulator module and the second voltage regulator module. The output end of the first voltage regulator module is connected to the RF amplifier module. The output end of the second voltage regulator module is connected to the main control module.

[0021] The output end of the negative output DC / DC conversion module is connected to the input end of the low dropout linear regulator module. The output end of the low dropout linear regulator module is connected to the laser.

[0022] In some examples, the RF amplifier module includes an RF input switch, an RF output switch, and an amplifier. The RF input switch has one input end and two output ends. The RF output switch has two input ends and one output end. The input end of the RF input switch is connected to an RF signal. One output end of the RF input switch is connected to the input end of the amplifier. The output end of the amplifier is connected to one input end of the RF output switch. The other output end of the RF input switch is directly connected to the other input end of the RF output switch. The output end of the RF output switch outputs an RF signal to the input end of the digital control attenuation module.

[0023] It should be understood that within the scope of the present invention, the above-mentioned various technical features of the present invention and the various technical features specifically described hereinafter (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be elaborated one by one here.

[0024] Advantages of the present invention:

[0025] The radio frequency optical fiber transmission transmitter of the present invention internally includes a pilot signal injection module and a logarithmic detector module. The pilot signal is transmitted through the main control module, and then the voltage detected by the logarithmic detector module is read to judge and monitor the situation of the RF link, helping maintenance personnel understand and troubleshoot the situation and reasons of the faults, so as to take corresponding measures to solve them. At the same time, the radio frequency optical fiber transmission transmitter of the present invention can support the transmission of signals of 5 GHz, 6 GHz, and even 20 GHz to 40 GHz. Description of the Drawings

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0027] Figure 1 It is a principle block diagram of an embodiment of the radio frequency optical fiber transmission transmitter of the present invention.

[0028] Figure 2 It is a signal path schematic diagram of the transmitter link test process of the present invention.

[0029] Figure 3 It is a principle block diagram of another embodiment of the radio frequency optical fiber transmission transmitter of the present invention.

[0030] Figure 4 It is a composition block diagram of the RF amplifier module of the present invention.

[0031] Figure 5 It is a circuit schematic diagram of the RF amplifier module of the present invention.

[0032] Figure 6 It is a circuit schematic diagram of the digital control attenuation module of the present invention.

[0033] Figure 7 It is a circuit schematic diagram of the pilot signal injection module of the present invention.

[0034] Figure 8 It is a circuit schematic diagram of the logarithmic detector module of the present invention.

[0035] Figure 9 It is an internal function schematic diagram of the laser of the present invention.

[0036] Figure 10 It is a composition block diagram of the laser driver module of the present invention.

[0037] Figure 11 It is a circuit schematic diagram of the laser driver module of the present invention.

[0038] Figure 12 It is a composition block diagram of the power supply module of the present invention.

[0039] Figure 13 It is a circuit schematic diagram of the negative output DC / DC conversion module in the power supply module of the present invention.

[0040] Figure 14 It is a circuit schematic diagram of the low dropout linear regulator module in the power supply module of the present invention.

[0041] Description of Reference Numerals of the Drawings:

[0042] 100 - Transmitter, 10 - Main Control Module, 20 - Transmitting - end RF Transmission Link, 21 - RF Amplifier Module, 211 - RF Input Switch, 212 - RF Output Switch, 213 - Amplifier, 2131 - First - stage Amplifier, 2132 - Second - stage Amplifier, 22 - Digital - controlled Attenuation Module, 30 - Laser Module, 31 - Laser, 32 - Laser Driver Module, 321 - Digital - to - Analog Converter, 322 - Precision Operational Amplifier, 323 - V / I Conversion Circuit, 40 - Pilot Signal Injection Module, 41 - Triode Array, 50 - Logarithmic Detector Module, 51 - Logarithmic Amplifier, 52 - Voltage Divider, 60 - Diagnostic Monitoring Signal Output Module, 61 - LED Indicator Module, 62 - Diagnostic Monitoring Signal Interface, 70 - Temperature Compensation Module, 80 - Power Supply Module, 81 - Adapter Module, 82 - Negative - output DC / DC Conversion Module, 821 - Negative - output Voltage Regulator Converter, 83 - Boosting Module, 84 - First Voltage Regulator Module, 85 - Second Voltage Regulator Module, 86 - Low - Dropout Linear Regulator Module, 861 - Low - Dropout Linear Regulator. Detailed Embodiment

[0043] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

[0044] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present utility model are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0045] In the present utility model, unless otherwise clearly defined and limited, terms such as "connection" and "fixation" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0046] In addition, in the present utility model, descriptions such as "first", "second", etc. are only for descriptive purposes and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second" may explicitly or implicitly include at least one such feature.

[0047] Please refer to Figure 1 , the present utility model provides a radio frequency optical fiber transmission transmitter 100, which includes a main control module 10, a transmitting end RF transmission link 20 and a laser module 30 connected to the main control module 10. The input end of the transmitting end RF transmission link 20 accesses an RF signal, and the output end of the transmitting end RF transmission link 20 is connected to the laser module 30. The laser module 30 converts the RF signal into an optical signal and then outputs it. The laser module 30 converts the RF signal into an optical signal and transmits it to the receiver end through an optical fiber.

[0048] The transmitter 100 of the present utility model further includes a pilot signal injection module 40, a logarithmic detector module 50 and a diagnostic monitoring signal output module 60 connected to the main control module 10. The pilot signal injection module 40 is also connected to the input end of the transmitting end RF transmission link 20, and the logarithmic detector module 50 is also connected to the output end of the transmitting end RF transmission link 20. As Figure 2 shown, the pilot signal injection module 40 is used to inject an RF signal for test diagnosis into the input end of the transmitting end RF transmission link 20, and this test diagnosis RF signal comes from the main control module 10. The logarithmic detector module 50 is used to obtain the RF level at the output end of the transmitting end RF transmission link 20 and send it back to the main control module 10. The main control module 10 determines whether there is an abnormality in the transmitting end RF transmission link 20 according to whether the transmitted RF level conforms to the current working state of the transmitter 100, and outputs the result through the diagnostic monitoring signal output module 60 for maintenance personnel to refer to.

[0049] Preferably, as Figure 2 shown, the diagnostic monitoring signal output module 60 of this embodiment includes an LED indication module 61 connected to the main control module 10 and / or a diagnostic monitoring signal interface 62 connected to the main control module 10. The LED indication module 61 can be provided with multiple or various colors of LED lights for display. For example, a red light indicates an abnormality, and a green light indicates normal, etc. The diagnostic monitoring signal interface 62 can be connected to intelligent devices such as a PC or a mobile phone, and then send the diagnostic signal or monitoring signal to the PC or mobile phone for display in combination with the corresponding application program.

[0050] Preferably, as Figure 2 and Figure 3As shown in the figure, the transmitting - end RF transmission link 20 includes an RF amplifier module 21 and a digital - control attenuation module 22 connected to the main control module 10. The input end of the RF amplifier module 21 is connected to the RF signal and the pilot - signal injection module 40. The output end of the RF amplifier module 21 is connected to the input end of the digital - control attenuation module 22, and the output end of the digital - control attenuation module 22 is connected to the input end of the laser module 30 and the logarithmic detector module 50.

[0051] The RF amplifier module 21 is used to amplify the input RF signal. The input RF signal has two sources. One is the real working signal input from the upper end of the transmission link, and the other is the diagnostic test signal input from the pilot - signal injection module 40. Since the input RF signals have different strength states, the RF amplifier module 21 selectively amplifies different - strength inputs to obtain appropriate gain and noise, and the specific selective amplification is controlled by the main control module 10.

[0052] Specifically, as Figure 4 shown in the figure, the RF amplifier module 21 of the present utility model includes an RF input switch 211, an RF output switch 212, and an amplifier 213. The RF input switch 211 has one input end and two output ends. The RF output switch 212 has two input ends and one output end. The input end of the RF input switch 212 is connected to the RF signal. One output end of the RF input switch 212 is connected to the input end of the amplifier 213. The output end of the amplifier 213 is connected to one input end of the RF output switch 212. The other output end of the RF input switch 211 is directly connected to the other input end of the RF output switch 212. The output end of the RF output switch 212 outputs the RF signal to the input end of the digital - control attenuation module 22.

[0053] The RF input switch 211 and the RF output switch 212 form a set of gating paths. The gating paths of the RF input switch 211 and the RF output switch 212 are controlled by the main control module 10. When LNA is On, the path between the RF input switch 211 and the amplifier 213 is activated. At this time, the input RF signal will be amplified by the amplifier 213 to obtain gain and then output through the RF output switch 212. When LNA is OFF, the path between the RF input switch 211 and the amplifier 213 is turned off. The RF signal is not amplified by the amplifier 213 but directly reaches the RF output switch 212 and is output to the next - level digital - control attenuation module 22. In the embodiment of the present invention, the LNA gain of the amplifier 213 is fixed, and the additional gain improves the noise performance of the module at the cost of sacrificing the maximum signal level.

[0054] Preferably, in this embodiment, the amplifier 213 is composed of multiple-stage amplifiers, including a first-stage amplifier 2131 and a second-stage amplifier 2132. This can reduce signal distortion while obtaining the required gain, so that the output signal has an appropriate signal-to-noise ratio.

[0055] Specifically, as Figure 5 shown, in the RF amplifier module 21 of the embodiment of the present invention, U2 is the first-stage amplifier 2131, U3 is the second-stage amplifier 2132, and the models of U2 and U3 both adopt TQP369180.

[0056] SW1 is the RF input switch 211, SW2 is the RF output switch 212, and the models of SW1 and SW2 both adopt JSW-63DR. The 2-pin of SW1 accesses the RF signal, the 2-output of SW2 outputs the RF signal, the 11-pin of SW1 is connected to the first pin of U2, and the 5-pin of SW2 is connected to the 3-pin of U2. The 7, 8, and 9 pins of SW1 are connected to the 7, 8, and 9 pins of SW2 through a current-limiting resistor and a filter capacitor. The 3-pin of U2 and the 1-pin of U3 are connected through a T-type attenuation circuit. Among them, in Figure 5 C1, C2, C27, C29, C30, and C31 are filter capacitors, C14, C16, C25, C33, C21, and C38 are RF signal transmission capacitors, R28, R29, R31, R37, R38, and R39 are current-limiting resistors, and R34, R35, and R36 are T-type attenuation circuits. The RF amplifier module 21 in the embodiment of the present invention can make the input RF signal obtain a total gain of 30 dB.

[0057] The digital control attenuation module 22 of the present utility model is used to attenuate the RF signal transmitted by the RF amplifier module 21, and the attenuation value can be adjusted between 0 dB and 31.5 dB, and the adjustment step is 0.25 dB. The digital control attenuation module 22 of the present utility model is placed after the LNA and before the laser module 30 to adjust and balance the link gain between the links, or set the performance preference of the noise relative to the maximum signal. The attenuation value can be set through the main control module 10 externally connected to a GUI (Graphical User Interface).

[0058] Specifically, as Figure 6 shown, in the digital control attenuation module 22 of the embodiment of the present utility model, U18 is a digital control attenuation chip, and the chip model is HMC624A. The RF signal is output from the 6-pin of U18, and after being attenuated by U18, it is output from the 13-pin of U18. The 2, 3, and 4 pins of U18 are connected to the main control module MCU. Figure 6Among them, C57, C58, C59, C60, C61, C48, C50, C52, and C56 are filter capacitors, and C38 and C62 are RF signal transmission capacitors.

[0059] As Figure 7 As shown in the figure, in this embodiment, the pilot signal injection module 40 includes a first current-limiting resistor R18, a second current-limiting resistor R21, a triode array 41, and a first RF signal transmission capacitor C15. The triode array 41 includes a first triode Q1 and a second triode Q2. The input ends of the first current-limiting resistor R18 and the second current-limiting resistor R21 are both connected to the control signal input by the main control module 10. The output end of the first current-limiting resistor R18 is connected to the base B1 of the first triode Q1. The output end of the second current-limiting resistor R21 is connected to the base B2 of the second triode Q2. The emitter E1 of the first triode Q1 is connected to the RF signal input by the main control module 10. The emitter E2 of the second triode Q2 is grounded. The collector C1 of the first triode Q1 is connected to one end of the first RF signal transmission capacitor C15. The other end of the RF signal transmission capacitor C15 is connected to the RF signal output node A. The collector C2 of the second triode Q2 is connected to the RF signal output node A.

[0060] The triode array 41 of the present utility model is a RF signal amplification and switch control device U16, with the model SMBT3904PN. Q1 and Q2 are integrated in U16. In this embodiment, the collector C1 of Q1 is also grounded through a pull-down resistor R13. The emitter E2 of Q2 is grounded through a pull-down resistor R25. A current-limiting resistor R16 is also connected between the collector C1 of Q1 and C15.

[0061] The main control module 10 generates a RF signal and inputs it to U16. U16 amplifies the RF signal and outputs it through node A. The pilot signal injection module 40 is used for the RF link transmission test and diagnosis function of the transmitter 100. When the test and diagnosis are selected on the transmitter 100, the RF pilot signal will be activated through the main control module 10 and injected into the input end of the RF transmission link 20 of the transmitter 100, that is, the input end of the RF amplifier module 21, through the pilot signal injection module 40, and the logarithmic detector module 50 integrated before the laser module 30 at the output end of the transmitter 100 will be enabled. These two together provide the test and diagnosis of whether the RF transmission link signal transmission in the module is normal. At the same time, the RF pilot signal will also be converted into an optical signal by the laser module 30 and transmitted to the receiver in the RF transmission link at the receiving end. Maintenance personnel, etc. can monitor the RF signal in the receiver to achieve the channel test of this RFOF link. In this embodiment, when the pilot test is activated, the color of the LED indicator light of the LED indicator module will turn cyan, indicating that a RF signal is being injected into the input end of the transmitter 100.

[0062] In the present utility model, as Figure 8 shown in, the logarithmic detector module 50 includes a logarithmic amplifier 51. In this embodiment, the logarithmic amplifier 51 is the component U12 in Figure 8 , and the logarithmic amplifier chip of model AD8317 is adopted for U12. U12 has a signal input pin 1 (INHI) and a signal output pin 5 (VOUT). The logarithmic detector module 50 of this embodiment further includes a second RF signal transmission capacitor C2, a third current-limiting resistor R8, and a voltage divider 52. The input end of the second RF signal transmission capacitor C2 is connected to the output end of the digital control attenuation module 22, the output end of the second RF signal transmission capacitor C2 is connected to the input pin 1 of the logarithmic amplifier 51, the output pin 5 of the logarithmic amplifier 51 is connected to the input end of the third current-limiting resistor R8, the output end of the third current-limiting resistor R8 is connected to the main control module 10, and the output pin 5 of the logarithmic amplifier 51 is also connected to the voltage divider 52.

[0063] Preferably, the voltage divider 52 of this embodiment is composed of voltage-dividing resistors R4 and R5 in a parallel relationship with R8. One end of R5 is connected to the output pin 5 of U12, the other end is connected to R4 and the 4th pin of U12, and the other end of R4 is grounded.

[0064] The logarithmic detector module 50 can accurately process the RF signal output from the digital control attenuation module 22 to the pin 1 of U12 and convert it into a corresponding voltage to be output to the MCU of the main control module 10. When the main control module 10 receives this voltage, it can accurately read the level of this RF signal. Then, the main control module 10 diagnoses the RF transmission link at the transmitting end according to the RF level fed back by the logarithmic detector module 50 and the working state of the current transmitter 100:

[0065] For example, the RF power decreases or increases, or the device is damaged resulting in the disconnection of the RF link, and whether the LNA ON and LNA Off states match the RF power, etc. If the read RF signal level does not match the LNA ON and Off states, it is diagnosed that the RF link is abnormal; if the read RF signal level is in line, the RF link diagnosis is considered to pass, and the diagnosis result is output through the diagnosis monitoring signal output module 60 for the maintenance personnel to refer to.

[0066] The pilot signal injection module 40 and the logarithmic detector module 50 of this embodiment can also be applied to the receiver end to test and diagnose the receiving end RF transmission link on the receiver.

[0067] In Figure 8Among them, C3, C5, C6, C7, C8, C9, and C11 are filter capacitors. R12 is connected to the 6th pin (TADJ) of U12 to adjust the performance for optimizing the input frequency.

[0068] Please continue to refer to Figure 3 , the laser module 30 of the transmitter 100 of the present utility model includes a laser 31 and a laser driving module 32. The input end of the laser 31 is connected to the output end of the digital control attenuation module 22. The output end of the laser 31 emits an optical signal. The laser 31 is also connected to the main control module 10 and the laser driving module 32. The laser 31 converts the RF signal into an optical signal, and the laser driving module 32 provides an accurate and stable bias current for the laser 31, so that the laser 31 emits a stable optical power output during operation.

[0069] The laser 31, as an optical signal emission source, converts the RF signal transmitted by the digital control attenuation module 22 into an optical signal for high-speed transmission. When activated, once its temperature reaches the target temperature (default set to 25 °C), it will arrange for the laser to turn on. This stabilization process depends on the ambient temperature and takes approximately 10 to 30 seconds to read the laser output power and display the LED status. The LED indication module 61 of this embodiment includes a three-color laser indicator light. When the control laser 31 is turned off, the laser indicator light changes in brightness. When the control laser 31 runs to make the laser enter its working state, the laser indicator light turns amber. When the laser is locked into its working range, the laser indicator light turns green.

[0070] Specifically, inside the laser 31 of this embodiment is as Figure 9 shown. It contains an LD (Laser Diode) and a PD (Photo Diode). The LD converts the RF signal into an optical signal, and the PD is used to monitor the optical power of the optical signal emitted by the LD, and returns the monitored optical power voltage value to the main control module 10 for monitoring.

[0071] Preferably, as Figure 3 shown, the transmitter 100 of the present utility model further includes a temperature compensation module 70 connected to the main control module 10. The temperature compensation module 70 is used to compensate for the error value of the power of the optical signal emitted by the transmitter 100 due to temperature characteristics. Due to the temperature characteristic drop of components under different temperature conditions, the test results of the same measured input signal at low temperature and high temperature will have a slight deviation compared to the test results at normal temperature. The temperature compensation module 70 uses a temperature sensor to detect the current temperature and compare it with the normal temperature of 25 °C, and compensates the measurement results at low temperature and high temperature according to the preset compensation value to keep the measurement results at low temperature and high temperature the same as the measurement results at normal temperature of 25 °C, reducing the measurement error caused by the temperature characteristics of components.

[0072] The emission characteristics of the laser 31 are closely related to the driving current. A stable optical signal can ensure the accuracy and reliability of data transmission and reduce the bit error rate. The laser driving module 32 can provide an accurate and stable bias current for the laser. By precisely controlling the current magnitude, the optical power output of the laser 31 can be adjusted, enabling the laser 31 to adapt to different application requirements.

[0073] In the prior art, the laser driving module is completed by a single laser driving chip. However, setting the bias current of the laser driving chip needs to be pre-set in the circuit design. This means that the output optical power of the laser in the transmitter will be set to a fixed value at the time of factory. Other APC (Automatic Power Control) functions, temperature compensation functions, etc. can only make the output optical power of the laser approach the pre-set value and cannot change the pre-set output optical power. In this case, for some transmitters that may need to change the output optical power, the manufacturer will add a variable resistor in the circuit for setting the bias current and manually adjust it according to requirements at the time of factory. This method is complex, inefficient and has unstable quality.

[0074] In the design of the present utility model, as Figure 10 shown, the laser driving module 32 includes three parts: a digital-to-analog converter 321, a precision operational amplifier 322 and a V / I conversion circuit 323 connected in sequence. The digital-to-analog converter 321 is also connected to the main control module 10, and the V / I conversion circuit 323 is also connected to the laser 31. The main control module 10 is connected to the digital-to-analog converter 321 through three lines: DIN, SCLK, and CS. Among them, DIN is the serial data input; SCLK is the serial clock input; CS is the chip select input pin. The main control module 10 transmits the data of the digital signal to the digital-to-analog converter 321. The digital signal is converted into an analog signal by the digital-to-analog converter 321. The analog signal then passes through a precision operational amplifier 322 and a V / I conversion circuit 323 to convert the obtained voltage signal into an adjustable current. The adjustment of the magnitude of this current is determined by the digital signal transmitted from the main control module 10 to the digital-to-analog converter 321. Thus, a digitally programmable current source is formed to provide a stable and programmably adjustable bias current for the laser 31 to drive the laser 31 to work.

[0075] The adjustment of the laser driving module 32 of the present utility model can monitor and adjust the current output optical power through the main control module 10 connected to the GUI (Graphical User Interface) installed on the PC. The operation is convenient, the interaction is simple, the stability is strong, which facilitates the installation and maintenance.

[0076] Preferably, as Figure 10 shown, the digital-to-analog converter 321 and the precision operational amplifier 322 of this embodiment can be integrated on one chip.

[0077] Specifically, as Figure 11 shown, in the laser driving module 32 of this embodiment, U20 is a chip integrating a 10-bit digital-to-analog converter (DAC) 321 and a precision operational amplifier 322, and the chip model is MAX5355EUA. U14 and U15 are triodes, forming a V / I conversion circuit. The models of U14 and U15 are both SMBT3904. The C1 pole of U14 is connected to the laser 31 to drive the laser 31. C55, C99, C51, C98, C54, C36, C45, and C39 are filter capacitors. D2 is an anti-reverse connection diode. R43, R45, R30, R52, R49, R47, and R53 are current-limiting resistors. R95 and R68 are reference voltage adjustment resistors of the U20 chip. R54, R56, R57, and R66 are laser voltage loads. R55 and R67 are output feedback resistors.

[0078] As Figure 3 shown, the transmitter 100 of the present invention further includes a power supply module 80. As Figure 12 shown, the power supply module 80 includes an adapter module 81, a negative-output DC / DC conversion module 82, a boost module 83, a first voltage stabilization module 84, a second voltage stabilization module 85, and a low-dropout linear voltage regulator module 86. The adapter module 81 outputs a DC voltage to the input ends of the negative-output DC / DC conversion module 82 and the boost module 83. The output end of the boost module 83 is connected to the input ends of the first voltage stabilization module 84 and the second voltage stabilization module 85. The output end of the first voltage stabilization module 84 is connected to the RF amplifier module 21. The output end of the second voltage stabilization module 85 is connected to the main control module 10. The output end of the negative-output DC / DC conversion module 82 is connected to the input end of the low-dropout linear voltage regulator module 86. The output end of the low-dropout linear voltage regulator module 86 is connected to the laser 31.

[0079] Since the RFOF transmitter 100 of the present invention belongs to an RF high-frequency transmission device, which requires higher power supply rejection and low noise, its power supply module 10 needs reasonable design. The specific description is as follows:

[0080] The adapter module 81 converts the external 110 / 220VAC power supply into a DC +5V output, and its rated power is 3W or higher.

[0081] The boost module 83 is used to boost DC5V to 6.5V for use by the first voltage stabilization module 84 and the second voltage stabilization module 85.

[0082] The first voltage stabilizing module 84: It is used to stabilize DC6.5V to DC6V for the RF amplifier module 21.

[0083] The second voltage stabilizing module 84: It is used to stabilize DC6.5V to DC3.3V for the main control module 10.

[0084] The negative output DC / DC conversion module 82: It is used to convert +5V to -5V for the low dropout (LDO) linear voltage regulator module 86. The negative output DC / DC conversion module 82 is also connected to the main control module 10, and the main control module 10 controls the on and off of the negative output DC / DC conversion module 82, thereby controlling the on and off of the laser 31. As Figure 13 shown, in the negative output DC / DC conversion module 82, U6 is the negative output voltage regulator 821, and the chip model is LT1931A. The VIN pin of U6 inputs +5VDC, and its SW pin outputs -5VDC. C78, C82, C9, C87, C92, C85, C86, C74 are power filter capacitors, L18, L29, L30 are power filter inductors, R75 is a pull-down resistor, D6 is a voltage regulator diode, and R72, R71, R74, R76 are load resistors.

[0085] The low dropout linear voltage regulator module 86: It has extremely low self-noise and a higher power supply rejection ratio, and is used to stabilize -5VDC to a voltage with higher power supply rejection and low noise for the laser 31.

[0086] As Figure 14 shown, in the low dropout linear voltage regulator module 86, U5 is the low dropout linear voltage regulator 861, and the model of U5 is ADP7182AUJZ. C75, C76, C81, C93, C89 are power filter capacitors, L20, L21 are power filter inductors, and R90, R91, R93 are load resistances.

[0087] Preferably, the diagnostic monitoring signal interface 62 of the transmitter 100 of the present invention can be various interfaces, such as USB, TYPE-C interface, etc. The RFOF transmitter 100 is also equipped with a GUI (Graphical User Interface). Workers, users or maintenance personnel can connect the transmitter 100 through a PC via the diagnostic monitoring signal interface 62, and all functions in the transmitter 100 can be monitored and set on the corresponding GUI, including:

[0088] 1. Real-time temperature monitoring.

[0089] 2. Set LNA ON / Off in the RF amplifier module.

[0090] 3. Set the attenuation amount in the digital control attenuation module.

[0091] 4. Set the laser to be turned on or off.

[0092] 5. Real-time monitor the RF signal level entering the laser.

[0093] 6. Real-time monitor and adjust the output optical power of the laser.

[0094] 7. The RF link test and diagnosis function involved in the pilot signal injection module.

[0095] The graphical user interface (GUI) greatly facilitates users and maintenance personnel. Maintenance personnel can perform operations such as device configuration and troubleshooting through operations such as clicking and dragging, without having to remember complex commands and parameters; users can quickly get started without undergoing specialized training. The intuitive graphical user interface helps maintenance personnel more intuitively understand and troubleshoot the situation and causes of faults, understand the operating status and performance of the system, provide a basis for maintenance decisions, and thus take corresponding measures to solve them.

[0096] The radio frequency optical fiber transmission transmitter 100 of the present utility model determines the situation of the RF transmission link through the pilot signal injection module 40 and the logarithmic detector module 50, helps maintenance personnel understand and troubleshoot the situation and causes of faults, and thus takes corresponding measures to solve them. At the same time, the transmitter 100 of the present utility model does not use a conventional laser driver chip to drive the laser, but uses a 10-bit DAC (digital-to-analog converter) and a V / I conversion circuit. The main control module sends a digital signal to the digital-to-analog converter, and then converts it into a current through the V / I conversion circuit to implement a digitally programmable current source. The remote adjustment of the output optical power of the laser module is realized, and the cost is reduced.

[0097] The above are only examples clearly illustrating the present utility model, and do not limit the patent scope of the present utility model. It is impossible to enumerate all implementation manners here. Any equivalent structural transformation made by using the content of the technical solution of the present utility model under the concept of the present utility model, or direct / indirect application in other related technical fields, is included in the patent protection scope of the present utility model.

Claims

1. A radio frequency optical fiber transmission transmitter, comprising a main control module, a transmitting end RF transmission link connected to the main control module, and a laser module. The input end of the transmitting end RF transmission link accesses an RF signal, and the output end of the transmitting end RF transmission link is connected to the laser module. The laser module converts the RF signal into an optical signal and then outputs it, characterized in that: It further includes a pilot signal injection module, a logarithmic detector module, and a diagnostic monitoring signal output module connected to the main control module. The pilot signal injection module is also connected to the input end of the transmitting end RF transmission link, and the logarithmic detector module is also connected to the output end of the transmitting end RF transmission link.

2. The RF optical fiber transmission transmitter according to claim 1, characterized in that, The transmitting end RF transmission link includes an RF amplifier module and a digital control attenuation module connected to the main control module. The input end of the RF amplifier module accesses the RF signal and the pilot signal injection module. The output end of the RF amplifier module is connected to the input end of the digital control attenuation module. The output end of the digital control attenuation module is connected to the input end of the laser module and the logarithmic detector module.

3. The radio frequency optical fiber transmission transmitter according to claim 1, wherein The pilot signal injection module includes a first current limiting resistor, a second current limiting resistor, a triode array, and a first radio frequency signal transmission capacitor. The triode array includes a first triode and a second triode; The input ends of the first current limiting resistor and the second current limiting resistor both access the control signal input by the main control module. The output end of the first current limiting resistor is connected to the base of the first triode, and the output end of the second current limiting resistor is connected to the base of the second triode. The emitter of the first triode is connected to the radio frequency signal input by the main control module, and the emitter of the second triode is grounded; The collector of the first triode is connected to one end of the first radio frequency signal transmission capacitor, and the other end of the radio frequency signal transmission capacitor is connected to the radio frequency signal output node. The collector of the second triode is connected to the radio frequency signal output node.

4. The radio frequency optical fiber transmission transmitter according to claim 1, characterized in that The logarithmic detector module includes a logarithmic amplifier, a second radio frequency signal transmission capacitor, a third current limiting resistor, and a voltage divider. The input end of the second radio frequency signal transmission capacitor is connected to the output end of the digital control attenuation module. The output end of the second radio frequency signal transmission capacitor is connected to the input pin of the logarithmic amplifier. The output pin of the logarithmic amplifier is connected to the input end of the third current limiting resistor. The output end of the third current limiting resistor is connected to the main control module. The output pin of the logarithmic amplifier is also connected to the voltage divider.

5. The radio frequency optical fiber transmission transmitter according to claim 2, wherein The laser module includes a laser and a laser driving module. The input end of the laser is connected to the output end of the digital control attenuation module. The output end of the laser emits an optical signal. The laser is also connected to the main control module and the laser driving module.

6. The radio frequency optical fiber transmission transmitter according to claim 5, wherein The laser driving module includes a digital-to-analog converter, a precision operational amplifier, and a V / I conversion circuit connected in sequence. The digital-to-analog converter is also connected to the main control module, and the V / I conversion circuit is also connected to the laser.

7. The RF optical fiber transmission transmitter according to claim 1, characterized in that The diagnostic monitoring signal output module includes an LED indication module connected to the main control module and / or a diagnostic monitoring signal interface connected to the main control module.

8. The radio frequency optical fiber transmission transmitter according to claim 1, characterized in that, It further includes a temperature compensation module connected to the main control module.

9. The radio frequency optical fiber transmission transmitter according to claim 5, wherein It further includes a power supply module, and the power supply module includes an adapter module, a negative output DC / DC conversion module, a boost module, a first voltage regulator module, a second voltage regulator module, and a low dropout linear regulator module; The adapter module outputs a DC voltage to the inputs of the negative output DC / DC conversion module and the boost module. The output end of the boost module is connected to the inputs of the first voltage regulator module and the second voltage regulator module. The output end of the first voltage regulator module is connected to the RF amplifier module. The output end of the second voltage regulator module is connected to the main control module; The output end of the negative output DC / DC conversion module is connected to the input end of the low dropout linear regulator module. The output end of the low dropout linear regulator module is connected to the laser.

10. The radio frequency optical fiber transmission transmitter according to claim 2, wherein The RF amplifier module includes an RF input switch, an RF output switch, and an amplifier. The RF input switch has one input end and two output ends. The RF output switch has two input ends and one output end. The input end of the RF input switch is connected to an RF signal. One output end of the RF input switch is connected to the input end of the amplifier. The output end of the amplifier is connected to one input end of the RF output switch. The other output end of the RF input switch is directly connected to the other input end of the RF output switch. The output end of the RF output switch outputs an RF signal to the input end of the digital control attenuation module.

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