CN108712167B - Standard frequency distribution module with self-adaptive frequency selection characteristic - Google Patents
Standard frequency distribution module with self-adaptive frequency selection characteristic Download PDFInfo
- Publication number
- CN108712167B CN108712167B CN201810505206.8A CN201810505206A CN108712167B CN 108712167 B CN108712167 B CN 108712167B CN 201810505206 A CN201810505206 A CN 201810505206A CN 108712167 B CN108712167 B CN 108712167B
- Authority
- CN
- China
- Prior art keywords
- frequency
- signal
- circuit
- filter
- standard frequency
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03L—AUTOMATIC CONTROL, STARTING, SYNCHRONISATION, OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
- H03L7/00—Automatic control of frequency or phase; Synchronisation
- H03L7/06—Automatic control of frequency or phase; Synchronisation using a reference signal applied to a frequency- or phase-locked loop
- H03L7/08—Details of the phase-locked loop
- H03L7/085—Details of the phase-locked loop concerning mainly the frequency- or phase-detection arrangement including the filtering or amplification of its output signal
- H03L7/093—Details of the phase-locked loop concerning mainly the frequency- or phase-detection arrangement including the filtering or amplification of its output signal using special filtering or amplification characteristics in the loop
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H17/00—Networks using digital techniques
- H03H17/02—Frequency selective networks
- H03H17/0202—Two or more dimensional filters; Filters for complex signals
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H21/00—Adaptive networks
- H03H21/0012—Digital adaptive filters
- H03H21/0025—Particular filtering methods
- H03H21/0027—Particular filtering methods filtering in the frequency domain
Abstract
The invention discloses a standard frequency distribution module with a self-adaptive frequency selection characteristic, which is provided with a radio frequency signal processing circuit, a microprocessor circuit and a power supply circuit, wherein when an external standard frequency main signal is input, the microprocessor circuit controls a radio frequency switch to switch a filter and combines the signal states of input and output signals of the standard frequency distribution module to identify the external standard frequency main signal, then generates a corresponding standard frequency distribution instruction and sends the standard frequency distribution instruction to the radio frequency signal processing circuit, and simultaneously controls the radio frequency switch to switch on the corresponding filter; the radio frequency signal processing circuit distributes the external standard frequency main signal into N paths of same standard frequency signals according to the standard frequency distribution instruction, and the N paths of same standard frequency signals are output after filtering. Furthermore, time frequency equipment with the standard frequency distribution module is also disclosed. The invention meets the requirements of different users on different frequencies and different quantities of standard frequency signal output of time frequency equipment, and can realize standard frequency distribution output in various frequencies in an intelligent frequency selection mode.
Description
Technical Field
The invention belongs to the technical field of time-frequency equipment in the special wireless communication industry, and particularly relates to an intelligent frequency marking distribution module for multiple standard frequency signals of time-frequency equipment.
Background
The frequency marking signal is a sine wave oscillation signal with a single frequency value which can provide high accuracy, and the frequency value is mainly 1MHz, 5MHz, 10MHz or 100 MHz.
The standard frequency signal is mainly generated by a quartz crystal oscillator or a high-accuracy atomic frequency standard, the crystal oscillator has been widely used due to the advantages of small volume, low cost, convenient use, good short-term stability of frequency and the like, almost all electronic products are used as a main frequency signal generating source, but the crystal oscillator also has frequencyPoor long-term stability, large frequency drift and the like. Therefore, the atomic frequency standard is often used for high-precision frequency signals, and at present, the atomic frequency standard mainly includes a cesium atomic frequency standard, a rubidium atomic frequency standard and a hydrogen atomic frequency standard, wherein the rubidium atomic frequency standard has the advantages of small volume, relatively low price, fast preheating, excellent index, low power consumption and the like, is widely applied, and can realize the accuracy of 1 × 10-11Stability 1X 10-12High index performance of magnitude.
The standard frequency source generally only outputs one path of standard frequency signal, the time frequency equipment needs to carry out frequency conversion, expansion, distribution and filtering processing on the standard frequency signal, outputs multiple paths of standard frequency signals with multiple frequencies, provides a low-phase-noise and high-stability standard frequency signal reference for users, and is an important component of systems such as communication, navigation and the like. In the prior art, the standard frequency distribution module can generally only distribute a certain fixed frequency, and when various frequency values need to be distributed, the standard frequency distribution module capable of distributing different frequencies needs to be respectively configured, so that the design and production workload of the module is greatly reduced, and the use convenience and the maintainability of a user are improved.
Disclosure of Invention
In order to solve the above problems, the present invention discloses a standard frequency allocation module with adaptive frequency selection and a time frequency device with the same, which are mainly used for meeting the requirements of different users on different frequencies and different quantities of standard frequency signal output of the time frequency device, and can realize the standard frequency allocation output of multiple frequencies in an intelligent way of adaptive frequency selection.
The invention discloses a standard frequency distribution module with a self-adaptive frequency selection characteristic, which is configured with a radio frequency signal processing circuit, a microprocessor circuit and a power circuit, wherein:
the microprocessor circuit comprises a microprocessor which is in communication connection with the upper computer;
the radio frequency signal processing circuit comprises a power distribution circuit and N paths of filter circuits which are connected in parallel in sequence, wherein each path of filter circuit is provided with M filters which are connected in parallel and a radio frequency switch which is connected with the microprocessor and is used for switching different filters; the filters are low-pass filters or band-pass filters, and the cut-off frequency (low-pass filter) or the center frequency (band-pass filter) of each filter is standard frequency and different in size; m and N are integers greater than 1; the radio frequency signal processing circuit also comprises a first signal coupling circuit positioned at the input end of the power distribution circuit, a first radio frequency power detection circuit connected with the first signal coupling circuit, a second signal coupling circuit positioned at the output end of the filter circuit and a second radio frequency power detection circuit connected with the second signal coupling circuit, and the first signal coupling circuit and the second radio frequency power detection circuit are respectively used for detecting the signal states of input and output signals of the standard frequency distribution module;
the power supply circuit is used for supplying power to the radio frequency signal processing circuit and the microprocessor circuit;
when an external standard frequency main signal is input, the microprocessor circuit controls the radio frequency switch to switch the filter, identifies the working frequency of the external standard frequency main signal by combining the detected signal states of the input and output signals of the standard frequency distribution module, then generates a corresponding standard frequency distribution instruction and sends the standard frequency distribution instruction to the radio frequency signal processing circuit, and controls the radio frequency switch to switch on the filter corresponding to the frequency of the external standard frequency main signal; the radio frequency signal processing circuit distributes the external standard frequency main signal into N paths of same standard frequency signals according to the received standard frequency distribution instruction, and then the signals are filtered by the connected filter circuit and then output.
As a preferable scheme, when the filter is a low-pass filter, the microprocessor switches the filter in the order from the cutoff frequency or the center frequency of the filter to the small one by controlling the radio frequency switch, and identifies the working frequency of the external standard frequency main signal by combining the signal states of the input and output signals, and specifically comprises:
configuring a radio frequency switch to switch on a first filter;
when the standard frequency main signal is detected to be input but no output signal exists, judging that the frequency of the external standard frequency main signal is the cut-off frequency corresponding to the first filter, and controlling the standard frequency distribution module to work at the cut-off frequency corresponding to the first filter;
when the input signal and the output signal are detected, switching to a second filter;
when the standard frequency main signal is detected to be input but no output signal exists, judging that the frequency of the external standard frequency main signal is the cut-off frequency corresponding to the second filter, and controlling the standard frequency distribution module to work at the cut-off frequency corresponding to the second filter;
when the input signal and the output signal are detected, switching to a third filter;
repeating the steps until an external standard frequency main signal is identified or the M-th filter is switched;
the cut-off frequencies of the first filter to the Mth filter are standard frequency and are reduced in sequence.
As a preferred scheme, when the filter is a band-pass filter, the microprocessor switches the filter in the order from the cutoff frequency or the center frequency of the filter to the small one by controlling the radio frequency switch, and identifies the working frequency of the external standard frequency main signal by combining the signal states of the input and output signals, specifically comprising:
configuring a radio frequency switch to switch on a first filter;
when an input signal and an output signal are detected, judging that the frequency of the external standard frequency main signal is the central frequency corresponding to the first filter, and controlling the standard frequency distribution module to work at the central frequency corresponding to the first filter;
when detecting that the standard frequency main signal is still input but no output signal exists, switching to a second filter;
when an input signal and an output signal are detected, judging that the frequency of the external standard frequency main signal is the central frequency corresponding to the second filter, and controlling the standard frequency distribution module to work at the central frequency corresponding to the second filter;
when detecting that the standard frequency main signal is still input but no output signal exists, switching to a third filter;
repeating the steps until an external standard frequency main signal is identified or the M-th filter is switched;
the center frequencies of the first filter to the Mth filter are standard frequency and are sequentially reduced.
As a preferred scheme, the radio frequency signal processing circuit further includes N through channels respectively connected in parallel with the filter circuit, and the switching between the filter circuit and the through channels is realized by the radio frequency switch, so as to detect the working states of the filter circuits.
Preferably, when the filter is a band-pass filter, the radio-frequency switch is configured to be initially turned on by a through path. Namely, the frequency screening is not carried out on the signals, each frequency signal can be output normally, and the signals are switched to the first filter for automatic frequency identification after output.
Preferably, the signal states of the input and output signals of the standard frequency distribution module are detected by sampling voltage measurement. The method specifically comprises the following steps: the first signal coupling circuit and the second signal coupling circuit respectively sample input and output signals, and the first radio frequency power detection circuit and the second radio frequency power detection circuit respectively convert the radio frequency power intensity of the sampled signals into sampled voltage signals with the same proportional size and send the sampled voltage signals to the microprocessor circuit; the microprocessor circuit compares the received sampling voltage signals output by the first radio frequency power detection circuit and the second radio frequency power detection circuit with corresponding preset values respectively so as to detect the signal states of the input signals and the output signals.
As a preferred scheme, the microprocessor circuit compares the received sampling voltage signals output by the first rf power detection circuit and the second rf power detection circuit with corresponding preset values, respectively, to detect the signal states of the input and output signals, specifically:
comparing the sampling voltage signal output by the first radio frequency power detection circuit with a preset first reference voltage and a preset second reference voltage respectively:
when the sampling voltage is greater than the first reference voltage, judging that an input signal exists and the amplitude is normal;
when the sampling voltage is between the first reference voltage and the second reference voltage, judging that an input signal exists, but the amplitude is smaller and abnormal;
when the sampling voltage is smaller than the second reference voltage, judging that no input signal exists;
comparing the sampling voltage signal output by the second radio frequency power detection circuit with a preset third reference voltage and a preset fourth reference voltage:
when the sampling voltage is not less than the third reference voltage, judging that an output signal exists and the amplitude is normal;
when the sampling voltage is between the third reference voltage and the fourth reference voltage, judging that an output signal exists, but the amplitude is smaller and abnormal;
and when the sampling voltage is less than the fourth reference voltage, judging that no output signal exists.
As a preferred scheme, when judging that the input external standard frequency main signal is abnormal, the microprocessor circuit reports the abnormal external standard frequency main signal to the upper computer, so that the upper computer can synthesize the signal detection conditions of other units to locate faults; and when the output signal is judged to be abnormal, judging that the standard frequency distribution module works abnormally, and reporting to the upper computer in time.
As a preferable scheme, the microprocessor circuit is further configured to receive a standard frequency allocation instruction sent by the upper computer, and control the radio frequency switch to switch on a filter corresponding to an external standard frequency main signal frequency based on the instruction to implement standard frequency allocation.
As a preferred scheme, the microprocessor circuit is further configured to receive a standard frequency allocation enabling instruction issued by the upper computer, and control the operation enabling of the power allocation circuit according to the standard frequency allocation enabling instruction, so as to activate or close the allocation output.
As a preferred scheme, the radio frequency switch is a single-pole multi-throw switch so as to switch different filters in the filter circuit.
Preferably, the filter adopts an elliptic function type LC low-pass/band-pass filter structure.
Preferably, each of the filter circuits is configured with an isolation amplifier. The isolation amplifier preferably drives the amplifiers to isolate the radio frequency signals from each other without cross talk effects.
Preferably, the input end of the power distribution circuit is provided with a low-noise amplification circuit. The low-noise amplification circuit is preferably a low-noise operational amplifier.
As a preferred solution, the power circuit includes a DC/DC switching buck filter circuit and an LDO linear voltage regulator circuit, the DC/DC switching buck filter circuit is used to convert a high voltage input into a low voltage output; the LDO linear voltage stabilizing circuit comprises a first LDO linear voltage stabilizing circuit and a second LDO linear voltage stabilizing circuit, and the first LDO linear voltage stabilizing circuit is used for processing the low voltage output by the DC/DC switch buck filter circuit and then supplying the low voltage to the radio frequency signal processing circuit for working; the second LDO linear voltage stabilizing circuit is used for processing the low voltage output by the DC/DC switch buck filter circuit and then supplying the low voltage to the microprocessor circuit for working, so that the noise of a radio frequency circuit power supply and a digital circuit power supply is reduced, and the mutual isolation effect is improved.
As a preferable scheme, the power supply circuit further comprises a working current detection circuit which converts the current working current into a voltage signal and outputs the voltage signal to the microprocessor circuit; the microprocessor circuit detects the working voltage signal output by the power supply circuit, compares the working voltage signal with a preset value to judge the working state of the power supply circuit, and reports the working state to an upper computer.
As a preferred scheme, the microprocessor circuit detects a voltage signal converted from the current working current, and compares the voltage signal with a preset value to judge the working state of the power supply circuit, and specifically includes:
the microprocessor compares the voltage signal with a preset fifth reference voltage and a preset sixth reference voltage:
when the working voltage is not less than the fifth reference voltage, judging that the current of the module is larger and the module works abnormally;
when the working voltage is between the fifth reference voltage and the sixth reference voltage, judging that the working current is normal;
and when the working voltage is lower than the sixth reference voltage, judging that the current of the module is small and the work is abnormal.
As a preferable scheme, the working frequency of the external standard frequency input signal is any one of 1MHz, 5MHz, 10MHz and 100MHz, and correspondingly, the cut-off frequency of the low-pass filter or the center frequency of the band-pass filter has four kinds of 1MHz, 5MHz, 10MHz and 100 MHz.
Furthermore, the invention also discloses a time frequency device which is configured with a standard frequency distribution module with any one of the characteristics.
Has the advantages that:
(1) through a plurality of low pass or band pass filters connected in parallel in the radio frequency signal processing circuit, filtering output of different standard frequency signals is realized, the requirements of different standard frequency distribution can be met, the module type is reduced, the universality and the number of backup parts are improved, and the later maintenance of products is facilitated.
(2) The number of the filter circuits, the types, the number and the frequency of the filters can be set according to requirements, the types of distributable frequencies are increased, the adaptability and the functionality of the standard frequency distribution module are improved, and the research, development, production and maintenance costs of equipment are reduced.
(3) Through the radio frequency power detection circuit at the input end and the output end of the radio frequency signal processing circuit, on one hand, the fault self-checking of the standard frequency distribution module can be realized, the intelligent level of equipment can be improved, and the troubleshooting difficulty of a user is reduced; on the other hand, the frequency selection characteristic of the filter can be utilized to realize self-adaptive frequency selection, and the cut-off frequency or the center frequency of the filter is switched according to the magnitude sequence, so that the frequency of the input standard frequency signal is quickly judged.
(4) Through the automatic detection of the input standard frequency, the working frequency of the module is automatically configured and reported to the upper computer, the intelligent capacity of the module is improved, and the misoperation risk of manual configuration is reduced.
(5) Through the through path, the working state of each filter in the filter circuit can be detected, and the fault can be conveniently and quickly positioned.
(6) The single-pole multi-throw switch is selected to realize the switching of different filters and through paths in the filter circuit, the insertion loss caused by the single-pole multi-throw switch has little influence on the standard frequency signal, and the influence of the switch isolation degree on the filters is also very small, thereby completely meeting the use requirements.
(7) The standard frequency distribution module provided by the invention can enable the time frequency equipment to have configurable frequency output capability, can select a self-adaptive frequency selection mode or an external control mode according to the user requirements, and has higher use flexibility so as to meet different requirements of multiple users.
Drawings
FIG. 1 is a block diagram of a standard frequency distribution module;
FIG. 2 is a schematic diagram of a standard frequency distribution module;
FIG. 3 is a block diagram of a microprocessor peripheral interface;
FIG. 4 is a block diagram of RF signal processing;
FIG. 5 is a schematic diagram of a low pass filter structure;
FIG. 6 is a simulated frequency response diagram of a 1MHz low pass filter;
FIG. 7 is a simulated frequency response diagram of a 5MHz low pass filter;
FIG. 8 is a simulated frequency response diagram of a 10MHz low pass filter;
FIG. 9 is a graph of insertion loss frequency response of the RF switch;
FIG. 10 is a graph of the isolation frequency response of the RF switch;
FIG. 11 is a schematic diagram of a low pass filter frequency scaling signal filtering frequency response;
fig. 12 is a schematic diagram of the frequency response of the frequency-scaled signal of the band-pass filter.
Detailed Description
The frequency-configurable standard frequency distribution module (called the standard frequency distribution module for short) with the self-adaptive frequency selection characteristic can adopt a 3U (100mm multiplied by 160mm) standard height and 4HP (1HP ═ 5.08mm) width structural form, a firm and durable 110-core band coding bit CPCI standard connector is selected for interconnecting with a low-frequency signal of an equipment backboard, and an SBMA (static mixer array) floatable blind plugging type radio frequency connector is selected for interconnecting with a radio frequency signal.
The standard frequency distribution module mainly comprises a power supply voltage reduction, filtering and current detection circuit, a radio frequency signal detection, amplification, distribution and filtering processing circuit, and a microprocessor detection, communication, control and management circuit. After any one kind of standard frequency signal is input from outside, three paths of same standard frequency signals can be distributed and output through the radio frequency part circuit, the working frequency of signal distribution can be switched by software configuration of the radio frequency circuit through the microprocessor, and after the input radio frequency signal (namely, the input signal) and the output radio frequency signal (namely, the output signal) respectively pass through power detection, A/D sampling is carried out on the microprocessor so as to judge whether the signals are normal or not. The module can communicate and manage with an upper computer through a bus communication interface, can adopt an external control mode or self-adaptive frequency selection to configure the current working frequency, and reports the working state of the module and the signal state of the input and output radio frequency interface. The power step-down, filter circuit step-down the 24V power of external input, output high quality, low ripple +3.3V and +5V voltage, supply the use of chip and active circuit in the module, current detection circuit is through real-time detection current working current, by microprocessor AD sampling back, judges whether module active circuit operating condition is unusual. And when the abnormality occurs, reporting to the equipment through the bus communication interface in time.
Considering that most of the time-frequency devices output 1MHz, 5MHz, and 10MHz sinusoidal frequency scaling signals, specific embodiments for the three frequency scaling signals are given below.
As shown in fig. 1, the embodiment discloses a standard frequency distribution module (this module for short), which mainly comprises a power supply part, a microprocessor, a radio frequency processing circuit, and the like. In the figure:
1 is a power detection circuit for input standard frequency signal, which converts the RF power intensity of the input standard frequency signal into a voltage signal with the same proportional size to facilitate the sampling of a microprocessor, and the voltage value V after the samplinginWith two reference voltages Vref1And Vref2Comparing, reference voltage Vref1And Vref2And determining after debugging and actual measurement according to the module, and recording in the module software. Whether the signals exist or not and whether the signals are normal or not are judged according to the following method:
when V isin≥Vref1When the input signal is available, the amplitude is normal;
when V isref1＞Vin＞Vref2When the input signal is normal, the amplitude is small and abnormal;
when V isin＜Vref2When it is time, the input signal is off.
The 2 is an input standard frequency signal amplifying, distributing and filtering circuit, the standard frequency signal processing is mainly completed through the circuit, and the index performance of the signal processing is mainly determined by the circuit and is a key circuit part of the module.
3 is a power detection circuit for outputting the frequency-marked signal, which respectively detects the three frequency-marked signals and samples the voltage value VOUTWith two reference voltages Vref3And Vref4Comparing, reference voltage Vref3And Vref4And determining after debugging and actual measurement according to the module, and recording in module software. Whether the signals exist or not and whether the signals are normal or not are judged according to the following method:
when V isOUT≥Vref3When the signal is in a normal range, the output signal is present;
when V isref3＞VOUT＞Vref4When the signal is normal, the output signal has small amplitude and is abnormal;
when V isOUT＜Vref4When it is time, the output signal is off.
And 4, a microprocessor circuit, which is a sampling, judging, deciding and controlling part of the module and is mainly realized by stored software, and meanwhile, the module is communicated with equipment (an upper computer) through the microprocessor, receives the management and configuration of the equipment and reports the current working state of the module in real time.
And 5, the power supply voltage reduction, filtering and working current detection circuit, wherein the power supply voltage reduction and filtering circuit reduces the voltage of +3.3V and +5V of an externally input +24V power supply through the voltage conversion of the DC/DC and the LDO, and performs power supply filtering processing on each output, thereby ensuring the quality of an output power supply and reducing the interference of power supply ripples on the radio frequency circuit and the crosstalk between the power supplies. The working current detection circuit converts the current working current into a voltage signal, and the voltage value V is sampled by the microprocessorIDETWith two reference voltages Vref5And Vref6Comparing, reference voltage Vref5And Vref6And determining after debugging and actual measurement according to the module, and recording in module software. Whether the working current of the module is normal or not is judged according to the following method:
when V isIDET≥Vref5When the working current is larger, the module works abnormally;
when V isref5＞VIDET＞Vref6At first, working electricityThe flow is normal;
when V isIDET＜Vref4When the working current is small, the module works abnormally.
As shown in fig. 2, a schematic diagram of an outline of a frequency-division distribution module shows a board card outline and an external interconnection interface form of the module, where:
the module printed board 6 meets the requirement of 3U structure size, has the thickness of 1.6mm, adopts a four-layer board structure design, and comprises an L1 signal layer, an L2 power supply layer, an L3 ground layer and an L4 signal layer if the printed board is designed in a laminated mode. Radio frequency signals are mainly routed through an L4 signal layer, a characteristic impedance reference layer is an L3 stratum, and radio frequency index performance can be effectively guaranteed by controlling the impedance matching characteristic of the standard frequency signals. The total thickness of the module printed board 6 is about 63.46mil, i.e. 1.61 mm.
The SBMA type bending socket is provided with four SBMA type bending sockets, the input and output standard frequency signals are interconnected with the equipment back plate through the connector, index performances such as characteristic impedance, insertion loss and isolation of the standard frequency signals can be effectively guaranteed, meanwhile, the connector has the floating characteristic, small structural errors during installation can be offset, the service life of the connector is prolonged, and the working reliability of the equipment is improved.
And 8, the CPCI standard connector with the coding positions is a firm and durable 2.0 mm-spacing 110 core, is provided with an anti-error positioning pin and can meet the blind plugging requirement of a module.
And 9, a module printed board and a structural member mounting hole are used for connecting and fixing the module printed board 6 and the module structural member, wherein the module structural member can play a role in shielding a radio frequency part circuit, so that internal circuit crosstalk and external interference are reduced, meanwhile, heat generated by the circuit part can be dissipated and transmitted to an equipment structural member through the module structural member, and a guarantee is provided for reliable and stable operation of the module.
In the embodiment, a 32-bit ARM processor chip STM32F103RCT6 with strong universality is selected as a microprocessor circuit, the microprocessor is based on an ARM 32-bit Cortex-M3 kernel and has the highest working frequency of 72MHz, a flash memory program memory of 512K bytes is provided with resources such as a USB, a CAN, 11 timers, 3 12-bit ADC converters, up to 13 communication interfaces, a plurality of quick multifunctional bidirectional I/O ports and the like, the requirements of the module on control, communication and the like are completely met, and the microprocessor has a large expandable space.
As shown in fig. 3, a block diagram of the peripheral interface of the microprocessor shows the main peripheral circuits and the internal resources used in the microprocessor. In the figure:
and 10 is a voltage reduction circuit of an external power supply of the microprocessor, and provides a +3.3V working power supply for the microprocessor.
And 11, a module working current detection circuit, wherein the converted voltage signal is sampled by a microprocessor to judge the working current condition of the module active circuit.
And 12, the CAN bus transceiver chip circuit is used for connecting CAN controller input and output signals in the microprocessor to a CAN physical bus through level conversion and impedance matching, and CAN be connected with an upper computer through a CAN bus.
And 13, a passive crystal, which is connected with the microprocessor and forms a crystal oscillator circuit with an oscillation circuit in the chip, the crystal oscillator circuit oscillates and outputs a main clock used by the microprocessor, and the inside of the microprocessor can perform frequency multiplication or frequency division based on the clock frequency to change the actual working clock frequency.
And 14, an online simulation debugging interface of the microprocessor is used for online debugging and programming of software codes.
And 15, a microprocessor debugging serial port can print software working state information and input an instruction to inquire the current working state and data.
The FLASH memory 16 is a non-volatile memory, and can permanently store parameter data such as module operating frequency and the like under the condition of no power supply, so that the FLASH memory can be conveniently restored to the previous operating state after power failure and restart.
And 17, inputting a standard frequency signal power detection signal, and judging the state of the input standard frequency signal after the A/D sampling of the microprocessor.
And 18, outputting a standard frequency signal power detection signal, and judging the state of the output standard frequency signal after the A/D sampling of the microprocessor.
And 19, a radio frequency circuit working frequency switching signal, wherein the module receives the working frequency information set by the equipment through a bus communication interface, and the frequency of the radio frequency circuit is switched through the interface to match the corresponding setting.
By the scheme, the microprocessor circuit can carry out power detection on the input and output standard frequency signals, judge whether the signal intensity is in a normal range or not so as to judge whether the signal exists or not, and report the judgment result to the upper computer at regular time; the microprocessor circuit can also detect the working voltage and the consumed current of the module in real time, wherein the working voltage comprises 24V voltage input in the power circuit and 3.5V and 5V voltage output, and the consumed current mainly refers to the total current and judges whether the total current is in a normal range or not, and the total current is reported to the upper computer when abnormality occurs. In addition to reporting the working state of each part in the module, in the embodiment, the microprocessor circuit can also automatically judge the frequency of the input standard frequency signal by combining the frequency selection characteristic of the filter bank, set the working frequency of the module according to the judgment result and generate a standard frequency distribution instruction, namely, a self-adaptive frequency mode; or through normal communication with the upper computer, the standard frequency distribution instruction issued by the upper computer is received, and the corresponding working frequency is switched according to the standard frequency distribution instruction, namely, an external control mode. Furthermore, the microprocessor circuit can also comprise an enabling instruction signal input end which receives an enabling instruction sent by the upper computer and controls whether the standard frequency is output or not according to the enabling instruction, and the function is mainly applied to the condition that the input frequency is unstable.
The radio frequency signal processing circuit is a main working circuit for standard frequency signal distribution, completes detection, amplification and distribution of input radio frequency signals, and then carries out different filtering on the standard frequency signals with different output frequencies through filter banks with different working frequencies, so as to achieve the optimal harmonic suppression effect. The filters are switched by the radio frequency switch, the switching control signal is output by the microprocessor, and the standard frequency signal output by each path displays the working state of the standard frequency signal through power detection. The radio frequency signal processing circuit can be controlled by the microprocessor, and activates or closes distribution output by controlling the work enable of the distribution chip; the frequency identification of the input standard frequency signal can be realized by switching the filters one by one under the control of the microprocessor.
As shown in fig. 4, a processing flow of the radio frequency signal is shown, in which:
The reference numeral 21 denotes a frequency-scaling signal coupling circuit, which separates a small part of power signals from the main rf signal by coupling, and indicates the power condition of the main signal in real time at a certain power ratio on the premise of not affecting the normal transmission and performance of the main signal, thereby playing a role of monitoring the main signal in real time.
The reference numeral 22 denotes a radio frequency power detection circuit, which mainly uses an active detector chip of ADI company, and after square-law detection of an input signal, the square-law circuit is used as a feedback amplifier for amplification, and after buffering and amplification, a voltage corresponding to an effective value of the input signal is output, and the radio frequency power detection circuit has good output linearity and stability for different input signals.
24 is a low noise amplifier circuit, which selects a low noise operational amplifier, which provides a certain power gain to amplify the input standard frequency signal, so as to satisfy the wider power range of the input signal, and generate lower noise, without greatly deteriorating the noise index of the standard frequency signal.
And 25, a power distribution circuit, which distributes and outputs three paths of same standard frequency signals to one path of input standard frequency signals.
26 is an isolation amplifier, and the driving amplifier is selected to isolate the three output standard frequency signals from each other, so that the influence of crosstalk can not be caused.
The module 27 is a radio frequency switch, and the module selects a single-pole four-throw (SP4T) switch to provide four switching channels, three channels are respectively used for low-pass filters with different frequencies, and the fourth channel is a through channel and can be used for channel self-checking to judge whether the filter has a fault. From the insertion loss frequency response of the radio frequency switch at different temperatures in fig. 9 and the isolation frequency response of the radio frequency switch at different switching channels in fig. 10 (wherein, RF 1-RF 4 correspond to 1MHz, 5MHz, 10MHz, and direct connection respectively), it can be clearly seen that the insertion loss of the selected radio frequency switch has little influence on the standard frequency signal, and the influence of the switch isolation on the filter is also very small, thereby completely meeting the use requirements.
28 is a 1MHz low-pass filter, and the low-pass filter adopts an elliptic function structure and has a better rectangular coefficient and a better transition band suppression performance. Fig. 5 is a schematic structural diagram of the low-pass filter, and based on the structure, values of the inductance and capacitance components in table 1 are obtained through simulation. Fig. 6 is a simulated frequency response diagram of a 1MHz low-pass filter, and it can be seen from the diagram that the low-pass filter has a low insertion loss and a high stop-band rejection, and the first, second, and third harmonics of a 1MHz standard frequency signal can all reach the rejection of more than 80dB, so that the standard frequency signal after isolation and amplification can basically ensure the high performance index of harmonic rejection of more than 85dB after filtering.
TABLE 1
29 is a 5MHz low pass filter, the low pass filter adopts an elliptic function structure, the schematic structural diagram is the same as that in fig. 5, fig. 7 is a simulation frequency response diagram of the 5MHz low pass filter, and table 2 is the component values of the 5MHz low pass filter. The low-pass filter has strong stop band inhibition capability, and can also ensure that the harmonic wave of the standard frequency signal output after filtering is inhibited by high performance index of more than 85 dB.
TABLE 2
The reference numeral 30 denotes a 10MHz low pass filter, which has an elliptic function structure, and the schematic structural diagram of the low pass filter is as shown in fig. 5, fig. 8 is a simulation frequency response diagram of the 10MHz low pass filter, and table 2 denotes component values of the 10MHz low pass filter. The low-pass filter has strong stop band inhibition capability, and can also ensure that the harmonic wave of the standard frequency signal output after filtering is inhibited by high performance index of more than 85 dB.
TABLE 3
31 is a power detection voltage of the frequency-scaled output signal, which is compared with two reference voltages Vref3And Vref4And comparing to judge whether the output signal is normal or not. Reference numeral 32 denotes a frequency-scaled output signal, and in the embodiment, there is a three-way signal output.
The power supply processing circuit provides stable and low-noise power supply for the radio frequency signal processing circuit and the microprocessor circuit, performs voltage reduction processing on an externally input power supply, provides power supply for the module active chip and the circuit, and is a basic guarantee circuit of the module. The design of the circuit adopts a high-efficiency DC/DC voltage reduction filter circuit and a low-noise LDO linear voltage stabilizing circuit, the conversion efficiency is ensured, the quality of an output power supply can be improved, and the miniaturization of the circuit is realized. The +3.3V voltage output by the power supply is mainly used for digital circuits such as a microprocessor and the like to work, the +5V voltage output by the power supply is mainly used for radio frequency part circuits to work, and the LDO linear voltage stabilizing filter circuit enables high isolation between two paths of output voltages, can avoid power crosstalk between the digital circuits and the radio frequency circuits, and ensures the index performance of radio frequency signals.
The working principle is as follows:
power distribution: through the coordination work of the three circuits, the frequency-configurable standard frequency distribution can be completed. For example, when a 1MHz signal is input at a standard frequency, the device operates in a 1MHz state by setting the standard frequency allocation module, the microprocessor performs corresponding switching configuration on the filter bank switch of the radio frequency circuit after receiving the signal through the bus communication interface, so as to meet the requirement of the operating frequency, outputs the standard frequency signal after three paths of allocation, and simultaneously stores the setting into a FLASH memory connected with the microprocessor, the setting is not changed again until the next time the device is reconfigured, otherwise, the device operates at the frequency, and is effective after power failure and restart.
Input and output power detection: the module can perform power sampling detection on the input standard frequency signals and all output standard frequency signals, and indicate the signal state of the standard frequency interface in real time. When the working current of the module is abnormal, the module can be reported to the equipment in time through detection and discovery.
Channel self-checking: when the radio frequency signal processing circuit is abnormal, whether the fault of the filter occurs can be detected through the through channel of the radio frequency switch.
It should be noted that, in the power allocation process, the standard frequency allocation module in the embodiment may directly configure the current operating frequency in an external control manner, or configure the current operating frequency by itself based on an adaptive frequency selection manner. The selection of which mode is adopted can be determined according to the relevant instructions issued by the upper computer, and the self-adaptive frequency selection mode can also be set as a default mode so as to improve the intelligence of the equipment.
The radio frequency signal processing circuit is controlled to work in a corresponding frequency state directly according to the standard frequency distribution instruction, and the mode is simple and is not repeated herein.
For the self-adaptive frequency selection mode, the method mainly comprises two parts of automatic identification of the standard frequency input frequency and automatic configuration of a processor:
and (3) automatic identification of standard frequency input frequency: the frequency of the standard frequency signal can be comprehensively judged by utilizing the screening function of the filter bank on the standard frequency of different frequencies and combining the identification of the existence of the input and output standard frequency signals under the ingenious filter switching.
Referring to fig. 11, in which: 33 is the frequency response of the 1MHz low-pass filter, which allows the 1MHz standard frequency to pass, and does not allow the 5MHz and 10MHz standard frequency to pass; 34 is the frequency response of the 5MHz low-pass filter, which can allow the standard frequency of 1MHz and 5MHz to pass, and cannot allow the standard frequency of 10MHz to pass; 35 is the 10MHz low pass filter frequency response, which allows 1MHz, 5MHz and 10MHz to pass; 36 is the 1MHz scale signal spectrum; 37 is the 5MHz scale signal spectrum; 38 is the 10MHz scale signal spectrum. Correspondingly, the process of frequency automatic identification is as follows:
the first step is as follows: the module is powered on, the default processor configures a filter bank to work in a 10MHz low-pass filter channel, and once any one of the input three frequencies of the standard frequency signal exists, the standard frequency signal is output;
the second step is that: when the input and output signals with the standard frequency are detected, one of the frequency signals is input;
the third step: switching a low-pass filter bank to work in a 5MHz low-pass filter channel;
the fourth step: when it is detected that there is a standard frequency input but there is no standard frequency output, it can be determined that the input standard frequency is 10 MHz;
the fifth step: when detecting that the standard frequency input and the standard frequency output still exist, indicating that the input is not 10MHz, and continuously switching the low-pass filter to work at the frequency of 1 MHz;
and a sixth step: when it is detected that there is a standard frequency input but there is no standard frequency output, it can be determined that the input standard frequency is 5 MHz;
the seventh step: when the fact that the standard frequency input and the standard frequency output still exist is detected, the input standard frequency can be judged to be 1 MHz.
Referring to fig. 12, in which: 39 is the frequency response of the 1MHz band-pass filter, which can allow the 1MHz standard frequency to pass through, and can not allow the 5MHz and 10MHz standard frequency to pass through; 40 is the frequency response of a 5MHz band-pass filter, which can allow 5MHz standard frequency to pass, and can not allow 1MHz and 10MHz to pass; 41 is the frequency response of the 10MHz band-pass filter, which can allow 10MHz to pass through, but cannot allow 1MHz and 5MHz to pass through; 42 is the 1MHz standard frequency signal spectrum; 43 is the 5MHz standard frequency signal spectrum; 44 is the 10MHz scale signal spectrum. Correspondingly, the process of frequency automatic identification is as follows:
the first step is as follows: when the module is powered on, the default processor configuration switch works in a through channel (namely a filter detection channel), and once any one of the input three frequencies of the standard frequency signal is input, the output is provided;
the second step is that: when the input and output signals with the standard frequency are detected, one of the frequency signals is input;
the third step: configuring a band-pass filter to work in a 10MHz filter channel;
the fourth step: when the input and output signals of the standard frequency are detected to be still provided, the input standard frequency can be judged to be 10 MHz;
the fifth step: when the standard frequency input is detected to be still available but the standard frequency output is not available, the input standard frequency can be judged to be 1MHz or 5MHz, and the band-pass filter is continuously switched to work at the frequency of 5 MHz;
and a sixth step: when the input and output signals of the standard frequency are detected to be still provided, the input standard frequency can be judged to be 5 MHz;
the seventh step: when it is detected that there is a standard frequency input but there is no standard frequency output, it can be determined that the input standard frequency is 1MHz frequency;
automatically configuring a processor: after the input standard frequency is detected, the microprocessor configures the corresponding filter channel to work according to the frequency, and can report the working frequency information to the upper computer.
It should be noted that, in the above detection process, if no standard frequency signal is input, the identification process is exited; and when the next time of detecting that a signal is input, re-entering a standard frequency identification process to automatically identify the frequency.
In summary, based on the standard frequency allocation module disclosed by the invention, self-allocation of various standard frequency signals can be realized simultaneously by a skillful software algorithm, and the universality and intelligence of the module are improved. In addition, through the detection, the current working state of the module can be well displayed, the abnormal conditions can be mastered in real time, and the self-perception capability is high. Through the series of detection, the current working state of the module can be well displayed, a better module self-checking function can be realized, and the parameter performance of the module can be mastered in real time.
Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above-described embodiments and application fields, and the above-described embodiments are illustrative, instructive, and not restrictive. Those skilled in the art, having the benefit of this disclosure, may effect numerous modifications thereto without departing from the scope of the invention as defined by the appended claims.
Claims (9)
1. A standard frequency distribution module with adaptive frequency selection, wherein, a radio frequency signal processing circuit, a microprocessor circuit and a power circuit are configured, wherein:
the microprocessor circuit comprises a microprocessor which is in communication connection with the upper computer;
the radio frequency signal processing circuit comprises a power distribution circuit and N paths of filter circuits which are connected in parallel in sequence, wherein each path of filter circuit is provided with M filters which are connected in parallel and a radio frequency switch which is connected with the microprocessor and is used for switching different filters; the filters are low-pass filters or band-pass filters, and the cut-off frequency of each low-pass filter or the center frequency of each band-pass filter is standard frequency and different in size; m and N are integers greater than 1; the radio frequency signal processing circuit also comprises a first signal coupling circuit positioned at the input end of the power distribution circuit, a first radio frequency power detection circuit connected with the first signal coupling circuit, a second signal coupling circuit positioned at the output end of each filter circuit and a second radio frequency power detection circuit connected with the second signal coupling circuit, and is used for detecting the signal states of input and output signals of the standard frequency distribution module in a sampling voltage measurement mode;
the power supply circuit is used for supplying power to the radio frequency signal processing circuit and the microprocessor circuit;
when an external standard frequency main signal is input, the microprocessor circuit controls the radio frequency switch to switch the filter, identifies the working frequency of the external standard frequency main signal by combining the detected signal states of the input signal and the output signal, generates a corresponding standard frequency distribution instruction and sends the standard frequency distribution instruction to the radio frequency signal processing circuit, and controls the radio frequency switch to switch on the filter corresponding to the frequency of the external standard frequency main signal; the power distribution circuit distributes the external standard frequency main signal into N paths of same standard frequency signals according to the received standard frequency distribution instruction, and then the signals are filtered by the switched-on filter circuit and then output;
the signal states of input and output signals of the standard frequency distribution module are detected in a sampling voltage measurement mode, and the method specifically comprises the following steps:
the first signal coupling circuit and the second signal coupling circuit respectively sample input and output signals, and the first radio frequency power detection circuit and the second radio frequency power detection circuit respectively convert the radio frequency power intensity of the sampled signals into sampled voltage signals with the same proportional size and send the sampled voltage signals to the microprocessor circuit;
the microprocessor circuit compares the received sampling voltage signals output by the first radio frequency power detection circuit and the second radio frequency power detection circuit with corresponding preset values respectively so as to detect the signal states of the input signals and the output signals.
2. The standard frequency distribution module according to claim 1, wherein when the filter is a low pass filter, the microprocessor circuit switches the filter in the order of the cutoff frequency of the filter from high to low by controlling the rf switch, and identifies the operating frequency of the external standard frequency main signal by combining the signal states of the input and output signals, and specifically comprises:
configuring a radio frequency switch to switch on a first filter;
when an input signal is detected but no output signal exists, judging that the working frequency of the external standard frequency main signal is the cut-off frequency corresponding to the first filter;
when the input signal and the output signal are detected, switching to a second filter;
when the input signal is detected but no output signal exists, judging that the working frequency of the external standard frequency main signal is the cut-off frequency corresponding to the second filter;
when the input signal and the output signal are detected, switching to a third filter;
repeating the steps until the working frequency of the external standard frequency main signal is identified or the working frequency is switched to the Mth filter;
wherein the cut-off frequencies of the first filter to the Mth filter are sequentially reduced.
3. The frequency-scaling distribution module of claim 1, wherein the rf signal processing circuit further comprises N pass-through paths respectively connected in parallel with the filter circuits, and the rf switch is used to switch between the filter circuits and the pass-through paths for detecting the fault status of the filter circuits.
4. The standard frequency distribution module according to claim 3, wherein when the filter is a band pass filter, the microprocessor circuit switches the filter in the order of the center frequency of the filter from high to low by controlling the rf switch, and identifies the operating frequency of the external standard frequency main signal by combining the signal states of the input and output signals, and specifically comprises:
configuring a radio frequency switch to initially switch on a through path;
when an input signal and an output signal are detected, configuring a radio frequency switch to switch on a first filter;
when an input signal and an output signal are detected, judging that the working frequency of the external standard frequency main signal is the central frequency corresponding to the first filter;
when detecting that there is an input signal but there is no output signal, switching to a second filter;
when an input signal and an output signal are detected, judging that the working frequency of the external standard frequency main signal is the central frequency corresponding to the second filter;
when detecting that there is an input signal but there is no output signal, switching to a third filter;
repeating the steps until an external standard frequency main signal is identified or the M-th filter is switched;
wherein, the center frequencies of the first filter to the Mth filter are reduced in sequence.
5. The standard frequency allocation module according to claim 1, wherein the received sampling voltage signals output by the first rf power detection circuit and the second rf power detection circuit are respectively compared with corresponding preset values to detect signal states of the input and output signals, specifically:
comparing the sampling voltage signal output by the first radio frequency power detection circuit with a preset first reference voltage and a preset second reference voltage respectively:
when the sampling voltage is greater than the first reference voltage, judging that an input signal exists and the amplitude is normal;
when the sampling voltage is between the first reference voltage and the second reference voltage, judging that an input signal exists, but the amplitude is smaller and abnormal;
when the sampling voltage is smaller than the second reference voltage, judging that no input signal exists;
comparing the sampling voltage signal output by the second radio frequency power detection circuit with a preset third reference voltage and a preset fourth reference voltage:
when the sampling voltage is not less than the third reference voltage, judging that an output signal exists and the amplitude is normal;
when the sampling voltage is between the third reference voltage and the fourth reference voltage, judging that an output signal exists, but the amplitude is smaller and abnormal;
and when the sampling voltage is less than the fourth reference voltage, judging that no output signal exists.
6. The standard frequency allocation module according to claim 1, wherein the microprocessor circuit is further configured to receive a standard frequency allocation command issued by the upper computer, and control the radio frequency switch to turn on and the corresponding filter based on the command to implement the standard frequency allocation.
7. The standard frequency allocation module according to claim 1, wherein the microprocessor circuit is further configured to receive a standard frequency allocation enable instruction issued by the upper computer, and control the operation enable of the power allocation circuit according to the standard frequency allocation enable instruction to activate or deactivate the allocation output.
8. The frequency scaling distribution module of claim 1, wherein the power circuit comprises a DC/DC switched buck filter circuit for converting a high voltage input to a low voltage output and an LDO linear voltage regulator circuit; the LDO linear voltage stabilizing circuit comprises a first LDO linear voltage stabilizing circuit and a second LDO linear voltage stabilizing circuit, and the first LDO linear voltage stabilizing circuit is used for processing the low voltage output by the DC/DC switch buck filter circuit and then supplying the low voltage to the radio frequency signal processing circuit for working; and the second LDO linear voltage stabilizing circuit is used for processing the low voltage output by the DC/DC switch buck filter circuit and then supplying the processed low voltage to the microprocessor circuit for working.
9. Time-frequency device, characterized in that it is equipped with a standard frequency allocation module with adaptive frequency selection characteristics according to any one of claims 1 to 8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810505206.8A CN108712167B (en) | 2018-05-24 | 2018-05-24 | Standard frequency distribution module with self-adaptive frequency selection characteristic |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810505206.8A CN108712167B (en) | 2018-05-24 | 2018-05-24 | Standard frequency distribution module with self-adaptive frequency selection characteristic |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108712167A CN108712167A (en) | 2018-10-26 |
| CN108712167B true CN108712167B (en) | 2021-11-23 |
Family
ID=63869528
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810505206.8A Active CN108712167B (en) | 2018-05-24 | 2018-05-24 | Standard frequency distribution module with self-adaptive frequency selection characteristic |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108712167B (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6639541B1 (en) * | 2000-08-29 | 2003-10-28 | The United States Of America As Represented By The Secretary Of The Navy | Device and method for detecting, measuring, and reporting low-level interference at a receiver |
| CN201499136U (en) * | 2009-09-03 | 2010-06-02 | 中国电子科技集团公司第十四研究所 | P-band self-selected frequency linear power amplifier |
| CN102201819A (en) * | 2011-03-07 | 2011-09-28 | 武汉理工大学 | Frequency synthesis source applied by DDS short-wave transmitter based on CPLD design |
| CN203574618U (en) * | 2013-11-06 | 2014-04-30 | 安徽白鹭电子科技有限公司 | Radio frequency signal source based on broadband frequency synthesizer ADF4351 |
| CN104052257A (en) * | 2013-03-15 | 2014-09-17 | 英特尔公司 | Spread-spectrum apparatus for voltage regulator |
| CN203951443U (en) * | 2014-07-22 | 2014-11-19 | 西安宏泰时频技术有限公司 | A kind of novel frequency distribution amplifier |
| CN107888186A (en) * | 2016-09-30 | 2018-04-06 | 南京誉葆科技有限公司 | A kind of active microwave source combination |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20160133256A (en) * | 2015-05-12 | 2016-11-22 | 삼성전자주식회사 | Broadcast receiving apparatus and control method thereof |
-
2018
- 2018-05-24 CN CN201810505206.8A patent/CN108712167B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6639541B1 (en) * | 2000-08-29 | 2003-10-28 | The United States Of America As Represented By The Secretary Of The Navy | Device and method for detecting, measuring, and reporting low-level interference at a receiver |
| CN201499136U (en) * | 2009-09-03 | 2010-06-02 | 中国电子科技集团公司第十四研究所 | P-band self-selected frequency linear power amplifier |
| CN102201819A (en) * | 2011-03-07 | 2011-09-28 | 武汉理工大学 | Frequency synthesis source applied by DDS short-wave transmitter based on CPLD design |
| CN104052257A (en) * | 2013-03-15 | 2014-09-17 | 英特尔公司 | Spread-spectrum apparatus for voltage regulator |
| CN203574618U (en) * | 2013-11-06 | 2014-04-30 | 安徽白鹭电子科技有限公司 | Radio frequency signal source based on broadband frequency synthesizer ADF4351 |
| CN203951443U (en) * | 2014-07-22 | 2014-11-19 | 西安宏泰时频技术有限公司 | A kind of novel frequency distribution amplifier |
| CN107888186A (en) * | 2016-09-30 | 2018-04-06 | 南京誉葆科技有限公司 | A kind of active microwave source combination |
Non-Patent Citations (2)
| Title |
|---|
| "A self-adaptive frequency selection common spatial pattern and least squares twin support vector machine for motor imageryelectroencephalography recognition";recognitionDuan Li等;《Biomedical Signal Processing and Control》;20171230;222-232 * |
| "一种超宽带自适应选频网络的设计";李新胜等;《微波学报》;20170430;第33卷(第2期);222-232 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108712167A (en) | 2018-10-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102109572B (en) | Method for testing and method for testing and controlling transmission chip | |
| US20190271999A1 (en) | Online Voltage Adjustment Circuit for Board Power Supply | |
| CN103973232A (en) | Apparatus for radio frequency integrated circuit | |
| CN108712167B (en) | Standard frequency distribution module with self-adaptive frequency selection characteristic | |
| WO2021129794A1 (en) | Auxiliary control circuit for power amplification module, power amplification module, and communication device | |
| CN208479599U (en) | A kind of frequency distribution module and time-frequency equipment that frequency is configurable | |
| CN209460388U (en) | Analog signals error Acquisition Circuit, system and analog signals calibrating installation | |
| CN201039101Y (en) | Power modulation filter frequency calibration device | |
| CN215072327U (en) | Multi-channel frequency conversion module | |
| CN114038181B (en) | Remote debugging device and server | |
| CN210894607U (en) | Microwave amplifier test system | |
| CN201681290U (en) | General equipment controller | |
| CN210894497U (en) | Ammeter system | |
| CN210348280U (en) | Auxiliary device of mass flow controller | |
| CN114567385A (en) | Integrated high-power signal source | |
| CN108900200B (en) | Industrial industry-oriented transparent transmission wireless communication system | |
| CN108599783A (en) | A kind of frequency distribution module that frequency is configurable | |
| CN101192091B (en) | Data card powering method and system | |
| CN205301521U (en) | Anti -interference digital process board test platform of general type | |
| CN101114817A (en) | Digital type charge amplifier | |
| CN114741022B (en) | Dual-backup control circuit power supply circuit carrier and configuration method | |
| CN211263652U (en) | Line load and fault detection system based on STM32 singlechip | |
| CN213659433U (en) | Computing device | |
| CN219105354U (en) | DC power microcomputer protection device based on DSP and FPGA | |
| CN219285325U (en) | Test platform |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |