CN114189263A - Multi-channel data coupler based on frequency division multiplexing and design method thereof - Google Patents
Multi-channel data coupler based on frequency division multiplexing and design method thereof Download PDFInfo
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- CN114189263A CN114189263A CN202111322669.9A CN202111322669A CN114189263A CN 114189263 A CN114189263 A CN 114189263A CN 202111322669 A CN202111322669 A CN 202111322669A CN 114189263 A CN114189263 A CN 114189263A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B3/00—Line transmission systems
- H04B3/02—Details
- H04B3/04—Control of transmission; Equalising
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J1/00—Frequency-division multiplex systems
- H04J1/02—Details
Abstract
The invention discloses a multi-channel data coupler based on frequency division multiplexing and a design method thereof, wherein an uplink channel coupling channel is arranged based on the frequency division multiplexing principle, and consists of a first matching transformer and a high-pass filter; the downlink channel coupling channel consists of a second matching transformer and a first low-pass filter; a DC supply path consisting of a first low pass filter and a second low pass filter. The invention realizes multi-path data coupling by using the passive device, and has simple design and strong application expandability.
Description
The technical field is as follows:
the invention belongs to the field of data communication, and particularly relates to a frequency division multiplexing-based multi-path data coupler and a design method thereof, which are applied to occasions for realizing multi-path data multiplexing transmission by adopting a pair of transmission lines.
Background art:
in the application occasions of petroleum logging, deep sea detection, television monitoring systems and the like, remote bidirectional data transmission and direct current power supply are needed. The common multi-core cable is adopted to realize bidirectional data transmission, the realization principle is simple, but the cable volume and the cost can become restriction factors due to long-distance transmission. Two ways of realizing bidirectional data transmission by a single cable, such as a single-core coaxial cable or a pair of twisted-pair cables, are mainly provided: the method comprises the steps of realizing two-way data transmission of a single cable by adopting time division multiplexing, and realizing transmission switching of uplink data and downlink data by transmission time slot control; the data coupler adopts a frequency division multiplexing mode to realize single-cable bidirectional data transmission, different paths of data are modulated to different carriers to be transmitted, and the data coupler is high in implementation complexity and cost under the common condition.
The invention content is as follows:
the technical problem to be solved by the invention is to provide a frequency division multiplexing-based multi-path data coupler, which realizes multi-path data coupling by utilizing a passive device, and has simple design and strong application expandability.
The technical solution of the present invention is to provide a frequency division multiplexing-based multi-path data coupler, which is based on the frequency division multiplexing principle and is provided with
The uplink channel coupling path consists of a first matching transformer and a high-pass filter;
the downlink channel coupling channel consists of a second matching transformer and a first low-pass filter;
a DC supply path, which is composed of a first low-pass filter and a second low-pass filter;
the downlink channel coupling path and the direct current supply path share a first low-pass filter, and the uplink channel coupling path and the downlink channel coupling path are connected at a cable end, so that frequency band isolation among different paths of signals is realized, and a multi-path coupling function is achieved.
Preferably, in the uplink channel coupling path, the first resistor and the first capacitor form a high voltagePass filter, cut-off frequency fHAllowing uplink data to be coupled into the transmission cable without loss, wherein the first matching transformer is in an isolated type, and the working frequency band satisfies fupThe data requirements of (1); the first resistor has impedance matching function to match the whole coupler impedance with the characteristic impedance of the cable, and at the cable end, the first capacitor and the first resistor form a low-resistance filter to prevent downlink signals and a direct-current power supply in the transmission cable from influencing an uplink data source and require fdownThe signal is attenuated by no less than 25 dB.
Preferably, in the downlink channel coupling path, the first inductor and the second capacitor form a first low-pass filter with a cut-off frequency fL1The first low-pass filter prevents the upstream data from passing through, for the frequency fupAttenuation of not less than 30dB, allowing fdownThe signal passes through without loss; the third capacitor and the second matching transformer form a downlink command coupling path, the third capacitor isolates direct current and low-frequency signals, and f is allowed while the influence of low-frequency components in the power supply signal on the downlink coupling path is preventeddownThe signal passes through the second matching transformer in a lossless mode, and the second matching transformer is in an isolation type; entire path to frequency fupThe attenuation of (2) is not less than 40dB, and the attenuation of the power frequency existing in the direct current power supply signal is not less than 100 dB.
As a preferred technical solution, in the dc power supply path, the second inductor and the fourth capacitor form a second low-pass filter, and the second low-pass filter is cascaded with the first low-pass filter, and is used for extracting a dc signal, blocking uplink data and downlink data signals, and requiring the pair fdownThe attenuation of the signal is not less than 40 dB.
Furthermore, the invention also provides a design method of the frequency division multiplexing-based multi-path data coupler, which comprises the following steps,
step 1, designing an uplink data rate f according to the requirement of the transmission information quantityupDownlink data rate fdownSo as to satisfy fup＞40×fdownDesigning the withstand voltage values of all inductors and capacitors according to the voltage and power requirements of direct current power supply;
step 3, the first inductor and the second capacitor form a first low-pass filter, and the cut-off frequency fL1The first low-pass filter prevents the upstream data from passing through, for the frequency fupAttenuation of not less than 30dB, allowing fdownThe signal passes through without loss; the third capacitor and the second matching transformer form a downlink channel coupling path, the third capacitor isolates direct current and low-frequency signals, and f is allowed while the influence of low-frequency components in the power supply signal on the downlink channel is preventeddownThe signal passes through the second matching transformer in a lossless mode, and the second matching transformer is selected to be in an isolation type; the whole path requirement is for the frequency fupThe attenuation of the power frequency is not lower than 40dB, and the attenuation of the power frequency existing in the direct current power supply signal is not lower than 100 dB;
and step 4, a second low-pass filter is formed by the second inductor and the fourth capacitor, is cascaded with the first low-pass filter and is used for extracting the direct current signal, stopping the uplink data signal and the downlink data signal and requiring fdownThe attenuation of the signal is not less than 40 dB.
As a preferred technical solution, in the design process, the mutual influence among the channels should be considered, and the first inductor, the second capacitor, the second inductor, the third capacitor, the fourth capacitor, and the second matching transformer should be considered to form a multi-stage filter according to the characteristics of the downlink channel.
Compared with the prior art, the invention has the following advantages after adopting the technical scheme: the design principle is simple, the engineering realizability is strong, the cost is low, different devices can be selected according to the power supply power to be transmitted, the installation volume and the power requirements can be considered, and the bidirectional transmission device can be suitable for application occasions of single-core coaxial cable bidirectional transmission and one-pair twisted-pair bidirectional transmission.
Description of the drawings:
FIG. 1 is a block diagram of a multicoupler of the present invention.
Fig. 2 is a schematic diagram of a multi-way data coupler circuit of the present invention.
The specific implementation mode is as follows:
the invention is further described with reference to the following figures and detailed description:
examples
As shown in FIG. 1, a multiplexing data coupler based on frequency division multiplexing is provided based on the principle of frequency division multiplexing
The uplink channel coupling path is composed of a first matching transformer T1 and a high-pass filter;
the downlink channel coupling path is composed of a second matching transformer T2 and a first low-pass filter;
a DC supply path, which is composed of a first low-pass filter and a second low-pass filter;
the downlink channel coupling path and the direct current supply path share a first low-pass filter, and the uplink channel coupling path and the downlink channel coupling path are connected at a cable end, so that frequency band isolation among different paths of signals is realized, and a multi-path coupling function is achieved. In the embodiment, the power supply, the uplink data and the downlink data are designed in different frequency bands, the uplink data are coupled into the transmission cable through the high-pass filter, the high-pass filter is reversely seen to have low-frequency suppression characteristics, namely, low-frequency signals are prevented from passing through, and the downlink data are greatly attenuated; the first low-pass filter and the second matching transformer are combined to carry out lossless output on the data of the downlink channel, and the data of the uplink channel is greatly attenuated; the second low-pass filter further reduces cut-off frequency, outputs energy channel signals, namely direct current power supply channel signals, simultaneously has large-amplitude attenuation on uplink channel data and downlink channel data, and realizes frequency band isolation among different channels of signals to realize multi-channel coupling by reasonably designing the cut-off frequency of the filter.
Specifically, in the uplink channel coupling path, the first resistor R1 and the first capacitor C1 form a high-pass filter, and the cut-off frequency fHAnd allowing uplink data to be coupled into the transmission cable without loss, wherein the first matching transformer T1 adopts an isolated type, and the working frequency band satisfies fupThe data requirements of (1); the first resistor R1 has impedance matching function to match the whole coupler impedance with the characteristic impedance of the cable, and at the cable end, the first capacitor C1 and the first resistor R1 form a low-resistance filter to prevent downlink signals and direct current power supply in the transmission cable from influencing an uplink data source and require fdownThe signal is attenuated by no less than 25 dB.
In the downstream channel coupling path, a first inductor L1 and a second capacitor C2 form a first low-pass filter with a cut-off frequency fL1The first low-pass filter prevents the upstream data from passing through, for the frequency fupAttenuation of not less than 30dB, allowing fdownThe signal passes through without loss; the third capacitor C3 and the second matching transformer T2 form a downlink command coupling path, the third capacitor C3 isolates direct current and low-frequency signals, the influence of low-frequency components in power signals on the downlink coupling path is prevented, and the f is allowed to be simultaneouslydownThe signal passes through the second matching transformer T2 in a lossless mode; entire path to frequency fupThe attenuation of (2) is not less than 40dB, and the attenuation of the power frequency existing in the direct current power supply signal is not less than 100 dB.
In the direct current power supply path, a second inductor L2 and a fourth capacitor C4 form a second low-pass filter, and the second low-pass filter is cascaded with the first low-pass filter and is used for extracting direct current signals, blocking uplink data signals and downlink data signals and requiring the pair fdownThe attenuation of the signal is not less than 40 dB.
The following describes a design method of a frequency division multiplexing-based multiplexer according to the present invention in detail with reference to fig. 2.
As shown in fig. 2, according to the data transmission rate requirement and the power supply power requirement, a single-core coaxial cable is selected as a transmission medium, the characteristic impedance is 50 ohms, the transmission distance is 3000 meters, the uplink data rate is 1.5Mbps, the downlink transmission rate is 25kbps, the power required by the direct current power supply is 200 watts, and the direct current power supply voltage is designed to be 300V.
The first matching transformer T1 is an isolation type transformer, the working center frequency point is 1.5MHz, the transformation ratio is 1:1, impedance characteristics are not influenced, and inductance of the single-side coil is not lower than 1 mH. In order to match the characteristic impedance of the transmission cable, considering the parallel connection of the inductor and the capacitor, the first resistor R1 is selected to be 56.2 ohms, and the cut-off frequency of the high-pass filter is fHDesigned at 280kHz, the first capacitor C1 is designed to be 10nF, and the amount of attenuation for the downstream data is 27 dB.
The first low-pass filter is composed of a first inductor L1 and a second capacitor C2, and the cut-off frequency is designed to be fL1Is 75kHz, for ensuring the downstream signal fdownLossless passage of fL1Should be greater than 3 xfdownTaking the first inductor L1 as 1mH and the second capacitor C2 as 10nF, the first low-pass filter pair uplink signal fupThe attenuation of (a) is 58 dB. The third capacitor C3 is selected to be 47nF, the second matching transformer T2 is an isolation type transformer, the transformation ratio is 1:1, and the second matching transformer is mainly used for coupling and outputting downlink signals.
The second low-pass filter is composed of a second inductor L2 and a fourth capacitor C4, and has a cut-off frequency fL2The design is 1.8kHz, the value of the second inductor L2 is 2.2mH, and the value of the fourth capacitor C4 is 3.3 uF. For downlink fdownThe attenuation of the signal reaches 45 dB.
In the design process, filters at all levels are considered separately, the model is simplified, parameter selection and engineering design realization are facilitated, and actual branches can influence each other, but the frequency band isolation is not influenced. The influence of the first inductor L1, the second capacitor C2, the second inductor L2, the fourth capacitor C4, the first capacitor C1 and the first resistor R1 should be considered when the power supply signal path is viewed from the cable end. For example, a multi-stage filter is formed by considering the first inductor L1, the second capacitor C2, the second inductor L2, the third capacitor C3, the fourth capacitor C4, and the second matching transformer T2 according to the characteristics of the downlink channel.
The invention adopts 9 passive devices, has simple design principle, strong engineering realizability and low cost, can select different devices according to the power supply power to be transmitted, can give consideration to the requirements of installation volume and power, and can adapt to the application occasions of single-core coaxial cable bidirectional transmission and one-pair twisted-pair bidirectional transmission.
The foregoing is illustrative of the preferred embodiments of the present invention only and is not to be construed as limiting the claims. All equivalent structures or equivalent process changes made by using the contents of the specification and the drawings of the invention are included in the scope of the patent protection of the invention.
Claims (6)
1. A frequency division multiplexing based multiplexed data coupler, characterized by: based on the frequency division multiplexing principle, setting
An upstream channel coupling path consisting of a first matching transformer (T1) and a high pass filter;
a downstream channel coupling path consisting of a second matching transformer (T2) and a first low pass filter;
a DC supply path, which is composed of a first low-pass filter and a second low-pass filter;
the downlink channel coupling path and the direct current supply path share a first low-pass filter, and the uplink channel coupling path and the downlink channel coupling path are connected at a cable end, so that frequency band isolation among different paths of signals is realized, and a multi-path coupling function is achieved.
2. The frequency division multiplexing-based multiplexed data coupler of claim 1, wherein: in the uplink channel coupling path, a first resistor (R1) and a first capacitor (C1) form a high-pass filter, and the cut-off frequency fHAllowing uplink data to be coupled into the transmission cable without loss, wherein the first matching transformer (T1) adopts an isolation type, and the working frequency band satisfies fupThe data requirements of (1); the first resistor (R1) has impedance matching function, so that the impedance of the whole coupler is matched with the characteristic impedance of the cable, and at the cable end, the first capacitor (C1) and the first resistor (R1) form a low-resistance filter to prevent downlink signals and direct current power supply in the transmission cable from influencing an uplink data source and require fdownThe signal is attenuated by no less than 25 dB.
3. The frequency division multiplexing-based multiplexed data coupler of claim 2, wherein: in the downstream channel coupling path, a first inductor (L1) and a second capacitor (C2) form a first low-pass filter, and the cut-off frequency fL1The first low-pass filter prevents the upstream data from passing through, for the frequency fupAttenuation of not less than 30dB, allowing fdownThe signal passes through without loss; the third capacitor (C3) and the second matching transformer (T2) form a downlink command coupling path, the third capacitor (C3) isolates direct current and low-frequency signals, and the influence of low-frequency components in the power supply signals on the downlink coupling path is prevented while f is alloweddownThe signal passes through without loss, and the second matching transformer (T2) adopts an isolation type; entire path to frequency fupThe attenuation of (2) is not less than 40dB, and the attenuation of the power frequency existing in the direct current power supply signal is not less than 100 dB.
4. The frequency division multiplexing-based multiplexed data coupler of claim 1, wherein: in the direct current power supply path, a second inductor (L2) and a fourth capacitor (C4) form a second low-pass filter, and the second low-pass filter is cascaded with the first low-pass filter and is used for extracting direct current signals, blocking uplink data signals and downlink data signals and requiring the pair fdownThe attenuation of the signal is not less than 40 dB.
5. The method of claim 4, wherein the step of designing the frequency division multiplexing-based multiplexer comprises: comprises the following steps of (a) carrying out,
step 1, designing an uplink data rate f according to the requirement of the transmission information quantityupDownlink data rate fdownSo as to satisfy fup＞40×fdownDesigning the withstand voltage values of all inductors and capacitors according to the voltage and power requirements of direct current power supply;
step 2, an uplink channel coupling path is formed by utilizing a first matching transformer and a high-pass filter, wherein the first resistor (R1) and the first capacitor (C1) form the high-pass filterWave, cut-off frequency fHAllowing lossless coupling of upstream channel data into the transmission cable; the first matching transformer (T1) adopts an isolation type, and the working frequency band should satisfy fupThe data rate requirement of; the first resistor (R1) has impedance matching function, so that the impedance of the whole coupler is matched with the characteristic impedance of the cable, and the first capacitor (C1) and the first resistor (R1) have low-frequency suppression function when viewed from the cable end, so that a downlink channel signal and a direct current supply path signal in the transmission cable are prevented from influencing an uplink channel data source, and the requirement on f is metdownThe attenuation degree of the signal is not lower than 25 dB;
step 3, the first inductor (L1) and the second capacitor (C2) form a first low-pass filter, and the cut-off frequency fL1The first low-pass filter prevents the upstream data from passing through, for the frequency fupAttenuation of not less than 30dB, allowing fdownThe signal passes through without loss; the third capacitor (C3) and the second matching transformer (T2) form a downlink channel coupling path, the third capacitor (C3) isolates direct current and low-frequency signals, the influence of low-frequency components in power signals on a downlink channel is prevented, and simultaneously f is alloweddownThe signal passes through without loss, and the second matching transformer (T2) is selected to be an isolation type; the whole path requirement is for the frequency fupThe attenuation of the power frequency is not lower than 40dB, and the attenuation of the power frequency existing in the direct current power supply signal is not lower than 100 dB;
step 4, a second low-pass filter is formed by the second inductor (L2) and the fourth capacitor (C4) and is cascaded with the first low-pass filter for extracting direct current signals, preventing uplink data signals and downlink data signals and requiring the pair fdownThe attenuation of the signal is not less than 40 dB.
6. The method of claim 5, wherein the step of designing the frequency division multiplexing based multiplexed data coupler comprises: in the design process, the mutual influence among all channels is also considered, and a first inductor (L1), a second capacitor (C2), a second inductor (L2), a third capacitor (C3), a fourth capacitor (C4) and a second matching transformer (T2) are considered to form a multi-order filter according to the characteristics of a downlink channel.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5717685A (en) * | 1989-04-28 | 1998-02-10 | Abraham; Charles | Transformer coupler for communication over various lines |
| US20040264399A1 (en) * | 2003-06-26 | 2004-12-30 | Broadcom Corporation | Transceiver for bidirectional frequency division multiplexed transmission |
| US20110038286A1 (en) * | 2009-08-17 | 2011-02-17 | Intersil Americas Inc. | Using frequency divisional multiplexing for a high speed serializer/deserializer with back channel communication |
| CN102752572A (en) * | 2012-07-05 | 2012-10-24 | 龚厚志 | System for realizing bi-directional data transmission in coaxial cable by utilizing frequency division multiplexing |
| US20190132026A1 (en) * | 2016-03-31 | 2019-05-02 | Safran Electronics & Defense | Device for transmission by power-line communication in an aircraft |
-
2021
- 2021-11-09 CN CN202111322669.9A patent/CN114189263A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5717685A (en) * | 1989-04-28 | 1998-02-10 | Abraham; Charles | Transformer coupler for communication over various lines |
| US20040264399A1 (en) * | 2003-06-26 | 2004-12-30 | Broadcom Corporation | Transceiver for bidirectional frequency division multiplexed transmission |
| US20110038286A1 (en) * | 2009-08-17 | 2011-02-17 | Intersil Americas Inc. | Using frequency divisional multiplexing for a high speed serializer/deserializer with back channel communication |
| CN102752572A (en) * | 2012-07-05 | 2012-10-24 | 龚厚志 | System for realizing bi-directional data transmission in coaxial cable by utilizing frequency division multiplexing |
| US20190132026A1 (en) * | 2016-03-31 | 2019-05-02 | Safran Electronics & Defense | Device for transmission by power-line communication in an aircraft |
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