CN207491093U - Adaptive digital television transmitter - Google Patents
Adaptive digital television transmitter Download PDFInfo
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- CN207491093U CN207491093U CN201721506179.3U CN201721506179U CN207491093U CN 207491093 U CN207491093 U CN 207491093U CN 201721506179 U CN201721506179 U CN 201721506179U CN 207491093 U CN207491093 U CN 207491093U
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Abstract
The utility model is related to adaptive digital television transmitters, N splitters divide the signal into multichannel, each power amplifier unit carries out phase to signal, after amplitude adjustment, it is exported after being sent into the synthesis of N combiners, after the oriented coupler sampling of output signal, it is sent into wave detector and obtains voltage signal, microprocessor receives the voltage signal, and output power is obtained according to the voltage power table of comparisons that microprocessor stores, output power is less than setting value, then microprocessor controls amplitude of each power amplifier unit (2) by method of successive approximation progress signal, phase adjustment, reach rated power, transmitter can adaptively be adjusted in 20 °~55 ° of ambient temperature range, ensure high-power synthesis in real time.
Description
Technical field
The utility model is related to straw treating device fields, specifically adaptive digital television transmitter.
Background technology
The positive high speed development of ground digital television broadcast in China, at present to the requirement of transmitter other than multiple functional, because
The wider 470-860MHz of frequency bandwidth for DTV, broadband performance and stable operation to transmitter also proposed new
Challenge.When the output power of individual devices is unsatisfactory for system requirements, power combing is a kind of the effective of raising system output power
Method, the design and development of proposition work(combiner for after of Wilkinson work(combiner device are laid a good foundation, but due to this
The bandwidth of operation of synthesizer is narrow, under conditions of standing-wave ratio ＜ 1.1 and isolation ＞ 20dB, relative bandwidth ＜ 20%, this
There are more document introductions to be widened the method for its bandwidth of operation afterwards, but although these methods improve bandwidth, but be the increase in loss, and
And also only static state, with the operation of equipment, environment temperature, the aging of device, combined coefficient can reduce.
Utility model content
The technical problem to be solved by the utility model is to provide adaptive digital television transmitter, to solve the prior art
Present in defect.
The technical solution that the utility model solves above-mentioned technical problem is as follows：
Adaptive digital television transmitter, including sequentially connected preamplifier (11), N splitters (1), power amplifier unit
(2), N combiners (3), directional coupler (4), wave detector (5) and microprocessor (6), the N splitters (1) divide the signal into
Multichannel corresponds to a power amplifier unit (2) per road signal；Each power amplifier unit (2) carries out signal phase, amplitude adjusts
Afterwards, it is sent into after N combiners (3) synthesize and exports, after the oriented coupler of output signal (4) sampling, be sent into wave detector (5) and obtain electricity
Signal is pressed, microprocessor (6) receives the voltage signal, and obtains according to the voltage power table of comparisons that microprocessor (6) stores defeated
Go out power, output power is less than setting value, then microprocessor (6) controls each power amplifier unit (2) to be carried out by the method for successive approximation
Amplitude, the phase adjustment of signal, reach rated power；
Further, the power amplifier unit (2) includes power amplifier microprocessor (20), and the power amplifier microprocessor (20) receives
Microprocessor (6) controls signal；Further include sequentially connected phase shifter (21), directional coupler 1 (23), fader
(25), power amplifier (27), directional coupler 2 (28)；The phase shifter (21) is micro- by digital regulation resistance 1 (22) and power amplifier
Processor (20) is connected into horizontal phasing control, and the fader (25) passes through digital regulation resistance 2 (26) and power amplifier microprocessor
Device (20) is connected to be adjusted into line amplitude；The directional coupler 1 (23) is passed through by wave detector 1 (24), directional coupler 2 (28)
Wave detector 2 (29) transmits a signal to power amplifier microprocessor (20) respectively；
The beneficial effects of the utility model are：Using the high-end high-speed chip of STM32 series, and using high accuracy number electricity
Position device and D/A converter, both ensure that powerful operational capability in turn ensured very high control accuracy, allow transmitter-
It is adaptively adjusted in 20 °~55 ° of ambient temperature range, ensures high-power synthesis in real time.
Description of the drawings
Fig. 1 is the utility model principle structure diagram；
Fig. 2 is the utility model power amplifier unit theory structure schematic diagram；
Fig. 3 is the utility model phase shifter circuit schematic diagram；
Fig. 4 is the utility model fader circuit diagram；
Reference numeral is as follows：
11st, preamplifier, 1, N splitters, 2, power amplifier unit, 20, power amplifier microprocessor, 21, phase shifter, 22, number
Potentiometer 1,23, directional coupler 1,24, wave detector 1,25, fader, 26, digital regulation resistance 2,27, power amplifier,
28th, directional coupler 2,29, wave detector 2,3, N combiners, 4, directional coupler, 5, wave detector, 6, microprocessor.
Specific embodiment
The principle and feature of the utility model are described below in conjunction with attached drawing, example is served only for explaining this practicality
It is novel, it is not intended to limit the scope of the utility model.
Such as the functional block diagram that Fig. 1 is adaptive digital television transmitter, digital TV transmitter system generates signal source
Radiofrequency signal carry out the preposition amplification of power adaptation, through N roads with the N splitters of phase constant amplitude be divided into multichannel be sent into power amplifier unit (root
The how many a power amplifier units of system, such as 3 power amplifier lists of 1KW transmitters are determined according to the power grade of digital TV transmitter
Member, 2 power amplifier units of 500W power amplifiers), power amplifier unit is put again into the consistency adjustment of line amplitude, phase, then by adjustment respectively
Signal after big is sent into synthesizer, and last signal is sent to microprocessor by detection, and microprocessor is according to synthetic effect and respectively
The input power detection of a power amplifier unit, according to algorithm, goes to control phase shifter, the fader of each power amplifier unit, repeatedly
Cycle adjustment reaches high efficiency power combing.
The operation principle of each section is explained in detail below.
1 system internal power combined coefficient is analyzed
In power synthetic technique, combined coefficient is to consider one of important references index of performance quality of power combing, together
Frequency electric signal synthesis two elements be：Amplitude, phase.Below by taking the synthesis of two-way power amplifier unit as an example, with regard to each element to power
The influence of synthesis is analyzed, and thus derives N roads power combining efficiency.
If the output power of two-way amplifier is respectively P1, P2, phase is respectively θ 1, θ 2, then gross output is：
It will respectively discuss specific to following several situations below：
Amplitude is identical, and phase is different
P1=P2 at this time substitutes into formula 1, and output power, which is calculated, is
P=P1[1+cos(θ2-θ1)] (formula 2)
Corresponding combined coefficient is：
From formula 3 it can be found that the phase difference between two paths of signals can generate large effect to combined coefficient, as θ 2- θ 1
At=0 °, efficiency is up to 100%；As θ 2- θ 1=180 °, efficiency minimum 0%.Table 1 gives phase dispersion degree pairing
Into the influence of efficiency.When two-way phase difference is no more than 5 °, power combining efficiency is more than 99%, meets design requirement.
Table 1
Phase is identical, during amplitude difference
As θ 1=θ 2, Δ P=P1/P2, output is calculated by formula 1 and synthesizes power
Corresponding combined coefficient is：
From formula 4 it can be found that influence of the dispersion of the consistent amplitude of phase to combined coefficient is smaller, when P1, P2 wherein
One be equal to 0 when, combined coefficient minimum 50%；As P1=P2=, combined coefficient is up to 100%.2 amplitude dispersion of table
Influence to combined coefficient.When two-way amplitude difference is no more than 1dB, power combining efficiency is more than 99%, meets design requirement.
Table 2
(3) when amplitude and phase exist simultaneously imbalance
Output synthesizes power
Corresponding combined coefficient is：
From formula 7 it can be found that when amplitude and phase exist simultaneously imbalance, and Magnitude Difference be no more than 2dB when, synthesis
Efficiency is affected by phase difference.3 amplitude of table, phase have discrete, the influence to combined coefficient η and loss L.When two-way width
Difference≤1dB is spent, during phase difference≤5 ° and amplitude difference power≤0.5dB, during phase difference≤10 °, combined coefficient is more than 99%, symbol
Close design requirement.
3 amplitude of table, phase have discrete, the influence to combined coefficient η and loss L
Above analysis is provided fundamental basis to next step successive approximation algorithm and foundation.
2. the design of phase shifter
What the present invention designed is voltage-controlled phase shifter, main 3dB electric bridges, varactor and 8 bit digitals using 90 ° of phase shifts
Potentiometer forms.
Such as Fig. 2, port1 is the input terminal of 3dB electric bridges, and port2 is straight-through end, and port3 is coupled end, and port4 is isolation
End.Input signal is divided into two-way after entering 3dB electric bridges, all the way into straight-through end 2, distinguishes all the way into 3,2 port of coupled end and 3 ports
Varactor is connect, the two paths of signals of entrance is made to be reflected back toward 1 and 4 ports respectively, is supported in this way in the reflection signal inversion of 1 port
Disappear, the reflection signal in-phase stacking in 4 ports.Therefore, signal is all exported from port 4, by the electricity for changing varactor
Anti- that the phase of output signal can be made to change, the design is using 4 varactors, on the basis of traditional circuit
Increase by two diodes of PIN1, PIN2, improve the linearity and range of phase shift, by select suitable varactor model and
Supply voltage, this phase shifter can accomplish the linear change in 120 °, while use 8 high accuracy number potentiometers, and stepping can
To reach 28=256, that is, phase shifting accuracy reaches 120 °/256=0.5 °, meets the requirement of design.
3. the design of fader
The utility model uses 8 high accuracy number potentiometers, controls the design method of analog attenuator HSMP-3866,
The balanced type π type attenuators that wherein HSMP-3866 is made of 4 PIN diodes, microprocessor is by controlling the voltage of SRC2
Change the gain reduction value of link, change the capacitance-resistance value of circuit by the supply voltage preset and adjustment, it can be the tune of gain
Adjusting range is controlled within 20dB, while uses 12 D/A conversion chips, and such degree of regulation can reach 20dB/4096
=0.005dB meets the requirement of design.
Due to the parameter of power amplifier be not it is fixed, can with environment temperature, supply voltage, output loading and change, because
This must update the parameter of look-up table at any time using feedback principle, and here it is adaptive techniques.
1., output signal sampled by directional coupler G, sampled signal obtains a voltage value by wave detector H, passes through
Look-up table obtains corresponding output power.If power does not reach design requirement at this time, into next step.
2., according to the analysis of front, microprocessor is sequentially adjusted in power amplifier unit by the preferential adjustment phase place of digital regulation resistance
1 arrives the phase shifter of N, after recycling for several times so that output power is detected as maximum at this time.
3., microprocessor by comparing the input signal of each power amplifier unit 1-N, sampled by directional coupler B and be sent into inspection
The performance number of wave device C and the output signal of each power amplifier unit sample the performance number for being sent into wave detector F by directional coupler E, sentence
Break which power difference it is maximum, microprocessor by digital regulation resistance adjust gain adjuster, according to the size of difference according to
The fader of secondary adjustment power amplifier unit, because there is the power difference of the output and input of each power amplifier unit, gives gain tune
The stepping of section provides reference frame, substantially reduces the number of cycle, after recycling for several times so that output power is detected as at this time
It is maximum.
4., cycle 2. 3. 2 steps so that output power Step wise approximation maximum value, until meeting design requirement.
5., when cycle for several times after still do not find and meet the value of design requirement, drop volume is taken to handle, continues cycling through 2. 3. 2
A step so that the value after output power Step wise approximation drop volume, until meeting design requirement.
From system as can be seen that microprocessor control section is the key that this system, the precision of control directly influences work(
The improvement degree of rate synthesis, this system uses the high-end high-speed chip of STM32 series, and uses high accuracy number potentiometer and D/
A converters both ensure that powerful operational capability in turn ensured very high control accuracy, allow transmitter at -20 °~55 °
Ambient temperature range in adaptively adjusted, ensure real-time high-power synthesis.
The above is only the preferred embodiment of the present invention, is not intended to limit the utility model, all in this practicality
Within novel spirit and principle, any modification, equivalent replacement, improvement and so on should be included in the guarantor of the utility model
Within the scope of shield.
Claims (2)
1. adaptive digital television transmitter, it is characterised in that：Including sequentially connected preamplifier (11), N splitters
(1), power amplifier unit (2), N combiners (3), directional coupler (4), wave detector (5) and microprocessor (6), the N splitters
(1) multichannel is divided the signal into, a power amplifier unit (2) is corresponded to per road signal；Each power amplifier unit (2) carries out phase to signal
It after position, amplitude adjustment, is sent into after N combiners (3) synthesize and exports, after the oriented coupler of output signal (4) sampling, be sent into detection
Device (5) obtains voltage signal, and microprocessor (6) receives the voltage signal, and the voltage power pair stored according to microprocessor (6)
Output power is obtained according to table, and output power is less than setting value, then microprocessor (6) controls each power amplifier unit (2) by gradually
Approximatioss carries out amplitude, the phase adjustment of signal, reaches rated power.
2. adaptive digital television transmitter according to claim 1, it is characterised in that：The power amplifier unit (2) includes
Power amplifier microprocessor (20), the power amplifier microprocessor (20) receive microprocessor (6) and control signal；It further includes sequentially connected
Phase shifter (21), directional coupler 1 (23), fader (25), power amplifier (27), directional coupler 2 (28)；It is described
Phase shifter (21) is connect with power amplifier microprocessor (20) into horizontal phasing control by digital regulation resistance 1 (22), the gain-adjusted
Device (25) is connect into line amplitude with power amplifier microprocessor (20) by digital regulation resistance 2 (26) and adjusted；The directional coupler 1
(23) power amplifier microprocessor is transmitted a signal to by wave detector 1 (24), directional coupler 2 (28) respectively by wave detector 2 (29)
Device (20).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721506179.3U CN207491093U (en) | 2017-11-14 | 2017-11-14 | Adaptive digital television transmitter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721506179.3U CN207491093U (en) | 2017-11-14 | 2017-11-14 | Adaptive digital television transmitter |
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| Publication Number | Publication Date |
|---|---|
| CN207491093U true CN207491093U (en) | 2018-06-12 |
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| CN201721506179.3U Active CN207491093U (en) | 2017-11-14 | 2017-11-14 | Adaptive digital television transmitter |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109495077A (en) * | 2018-11-08 | 2019-03-19 | 苏州全波通信技术股份有限公司 | Adaptive digital amplitude modulation and phase modulation system |
| CN110597348A (en) * | 2019-09-20 | 2019-12-20 | 成都沃特塞恩电子技术有限公司 | Power synthesis method and system |
| CN111654254A (en) * | 2020-05-25 | 2020-09-11 | 广西广播电视技术中心 | Radio frequency power synthesis self-adaptive adjusting method |
-
2017
- 2017-11-14 CN CN201721506179.3U patent/CN207491093U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109495077A (en) * | 2018-11-08 | 2019-03-19 | 苏州全波通信技术股份有限公司 | Adaptive digital amplitude modulation and phase modulation system |
| CN110597348A (en) * | 2019-09-20 | 2019-12-20 | 成都沃特塞恩电子技术有限公司 | Power synthesis method and system |
| CN111654254A (en) * | 2020-05-25 | 2020-09-11 | 广西广播电视技术中心 | Radio frequency power synthesis self-adaptive adjusting method |
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Legal Events
| Date | Code | Title | Description |
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| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| PE01 | Entry into force of the registration of the contract for pledge of patent right |
Denomination of utility model: Adaptive digital television transmitter Effective date of registration: 20230717 Granted publication date: 20180612 Pledgee: Bank of Jiangsu Limited by Share Ltd. Shanghai branch Pledgor: SHANGHAI DONGZHOU LAWTON TELECOM Co.,Ltd. Registration number: Y2023310000378 |
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| PE01 | Entry into force of the registration of the contract for pledge of patent right |