Embodiment
The present invention provides a kind of ATT control methods of management type family expenses photoreceiver, for management type family expenses photoreceiver.
The structure of whole management type family expenses photoreceiver as shown in figure 1, its mainly by connector, photoelectric switching circuit (PIN w/
OWDM), light power detection circuit, MCU, two amplifiers, numerical-control attenuator, RF level sensitive circuits, AGC signals transmission electricity
Road, ATT signal circuits and signal acquisition circuit composition.
Wherein light power detection circuit, MCU and AGC signal circuits composition AGC control circuits, luminous power detection electricity
The input on road is connected with photoelectric switching circuit, output end and MCU optical power signals input port connect.MCU AGC control letters
Number output end passes through the AGC control terminals of AGC signal circuits and numerical-control attenuator and connected.
Wherein RF level sensitive circuits, MCU and ATT signal circuits composition ATT control circuits, RF level sensitive circuits
Input be connected with signal acquisition circuit, the output ends of RF level sensitive circuits and MCU RF sampled levels input port connect.
MCU ATT control signal outputs are connected by the ATT control terminals of ATT signal circuits and numerical-control attenuator.
When carrying out ATT controls using ATT control circuits, its method comprises the following steps:
(1) MCU is sampled using RF level sensitive circuits to the RF radiofrequency signals that current photoreceiver exports, and obtains RF
RF signal values;
(2) attenuation being currently needed for that user is set is received, and is tabled look-up according to the attenuation, finds ATT controls
Magnitude of voltage;
(3) control voltage of two-stage amplifier is adjusted according to the ATT control voltages value, realizes ATT controls.
The table looked into step (2) just obtains by test, then stores the table and is read for MCU.Make
During the table, we are tested 50 amplifier IC, take its average value to realize ATT functions, and resulting table is:
After 1550nm or 1310nm optical signals are converted into electric signal by photoelectric switching circuit, one-level amplifying circuit is sent to,
Signal after one-level is amplified is sent to numerical-control attenuator, and the signal after decay after two level is amplified, becomes required and penetrated again
Frequency RF signals simultaneously export.When the first order is amplified, (mainly luminous power is sampled to the luminous power currently inputted by MCU
Detect circuit realiration), accurate Output optical power is drawn, and first order amplifier is adjusted by the size of input optical power
Control voltage, i.e. AGC functions;When two level is amplified, the radio frequency rf signal currently exported is sampled by MCU (mainly
RF level sensitive circuits are realized), and the control voltage of second level amplifier, i.e. ATT functions are adjusted according to the attenuation of setting.
Whole management type family expenses photoreceiver can be realized carries out compatibility with the ONU of other producers, and receiver and ONU are pacified
In a compact shell, unified fiber entering household scheme is realized, while radio and TV operator can be used up with real time inspection man and be connect
Running parameter (input optical power, output level, the photoreceiver operating temperature, and can be worked in real time according to receiver of receipts machine
State realizes the output level of remote adjustment receiver).Photoreceiver can realize optical receiver module and other by connector
The interaction of module, its interactive information mode have following 3 kinds of modes:UART, I2C and SPI.
The composition of whole management type family expenses photoreceiver is described in detail below:
The present embodiment provides a kind of AGC signal circuits, as shown in Fig. 2 it is mainly by resistance R1, resistance R2, resistance
R3, electric capacity C1, electric capacity C2, amplifier U1, resistance R4, resistance R5, electric capacity C3, electric capacity C4 and amplifier U2 compositions.Resistance R1's
One end connection power supply, the other end pass sequentially through resistance R2, resistance R3 connection amplifiers U1 positive input.Resistance R2, resistance
It is grounded between R3 by electric capacity C1.Amplifier U1 positive input is grounded by electric capacity C2.Resistance R4 and electric capacity C3 are connected in parallel on
Between amplifier U1 itself reverse input end and output end.Amplifier U1 reverse input end is grounded by resistance R5.Amplification
Device U1 output end connection amplifier U2 positive input.Amplifier U2 reverse input end is connected with its output end.Amplification
It is grounded between device U1 output end and amplifier U2 positive input by electric capacity C4.Electric capacity C4 uses variable capacitance.Resistance
MCU AGC control signal outputs, the AGC controls of amplifier U2 output end numerical-control attenuator are connected between R1 and resistance R2
End connection.
Ripple how is reduced in the MCU signals transmissions that AGC signal circuits mainly solve, improves DAC outputs
The problem of responsiveness.It is used for the occasion of DA conversions in PWM, rc filter circuit is the important step of relation conversion effect.By RC
We can substantially calculate the discharge and recharge frequency of capacitance-resistance link to charge and discharge electric constant, be generally and obtained preferable filter effect,
This frequency will be much smaller than PWM output frequency (being less than a quarter).Generally, when the smaller R of C are larger, DA conversions
The voltage loss very little gone out, but ripple is but very big;When the larger R of C are smaller, the voltage loss that DA is changed out is very big, but ripple
It is relatively small.So less filter capacitor must be used when the accurate DA for needing progress Linearity very high is changed, and as far as possible
Avoid using electrolysis class electric capacity.And in order to obtain stronger signal output, it must also add one-level high-performance after RC inertial elements
Voltage follow, the then electrochemical capacitor in the place of follower output plus filtering, for smooth RC inertial elements
Ripple.But this is not enough, because more AC harmonic composition may be contained in output voltage at this moment, if processing is not
When follower is possible to self-excitation.Solution is exactly to use a small decoupling capacitance.And the placement of electric capacity here is sequentially
Must be electrochemical capacitor preceding, decoupling capacitance is rear!If output voltage precision and Linearity are less demanding, but will to ripple
Ask but very high, or when this voltage ratio is more fixed, the larger filtering of electric capacity can be used to combine.Because although bulky capacitor
DC losses are larger, but we can reach the output voltage of requirement by adjusting PWM duty cycle, or pass through one-level AD
The feedback of conversion realizes the output of accurate fixed voltage.Simply still to add voltage order one follower here, in order to rear class
Acquisition Circuit is used, and AD collection points are placed at follower output.
In actual use, arranged in pairs or groups for the ease of circuit, the resistance of second-order low-pass filter and capacitance selection are by we
It is onesize, therefore second-order low-pass filter is as follows by frequency calculation formula:
The AGC signal circuits are tested using oscillograph, its oscillograph test circuit figure is as shown in figure 21, makes
The result for testing to obtain with oscillograph is as shown in figure 22, and as seen from the figure, the circuit is consumed from upper electricity to 95% dutycycle
Time is 116.923ms, fully meets our application.
The present embodiment provides a kind of ATT signal circuits, and the transmission circuit is similar with AGC transmission circuit structures, and it has
Body structure as shown in figure 3, ATT signal circuits by resistance R6, resistance R7, resistance R8, electric capacity C5, electric capacity C6, amplifier U3,
Resistance R9, resistance R10, electric capacity C7, electric capacity C8 and amplifier U4 compositions.Resistance R6 one end connection power supply, the other end leads to successively
Cross resistance R7, resistance R8 connection amplifiers U3 positive input.It is grounded between resistance R7, resistance R8 by electric capacity C5.Amplification
Device U3 positive input is grounded by electric capacity C6.Resistance R9 and electric capacity C7 be connected in parallel on the amplifier U3 reverse input ends of itself with
Between output end.Amplifier U3 reverse input end is grounded by resistance R10.Amplifier U3 output end connection amplifier U4's
Positive input.Amplifier U4 reverse input end is connected with its output end, output end and the amplifier U4 of the amplifier U3
Positive input between be grounded by electric capacity C8.Electric capacity C8 is variable capacitance.Connect MCU's between resistance R6 and resistance R7
ATT control signal outputs, the ATT control terminals connection of amplifier U4 output end numerical-control attenuator.Due to being transmitted with AGC signals
The structure of circuit is similar, thus the circuit can equally play a part of AGC signal circuits.
Whole management type family expenses photoreceiver removes the circuit structure of MCU parts as shown in figure 4, it is mainly by Power convert
Circuit, system interface, photoelectric switching circuit, light power detection circuit, RF level sensitive circuits figure, one-level amplifying circuit, numerical control
Attenuator, second amplifying circuit and RF signal acquisition circuits composition.
The concrete structure of power-switching circuit as shown in figure 5, its mainly by electric capacity C9, electric capacity C10, electric capacity C11, electric capacity
C12, electric capacity C13, electric capacity C14 compositions.
The concrete structure of system interface as shown in fig. 6, its mainly by ONU (i.e. optical network unit) MCU chip and each
The peripheral circuit of pin is formed.
The concrete structure of photoelectric switching circuit as shown in fig. 7, its mainly by electric capacity C17, resistance capacitance C18, resistance R13,
Resistance R14, inductance L1, PIN photodiode and inductance coil composition.The negative pole of PIN photodiode was both connect by electric capacity C17
Ground, and direct power supply, one end that its positive pole passes through inductance L1 connection inductance coils.The other end of inductance coil passes through resistance R13
Light power detection circuit is connected, the end is also grounded by electric capacity C18, resistance R14 respectively simultaneously.The middle part connection one of inductance coil
Level amplifying circuit.
The concrete structure of light power detection circuit as shown in figure 8, its mainly by resistance R35, amplifier U5, resistance R36, electricity
Hinder R37, resistance R38, resistance R12, electric capacity C15, resistance R11, electric capacity C16 and amplifier U6 compositions.Amplifier U5 output end
Amplified by the OPTIC_ALM interface clock signals of resistance R35 connection system interfaces, positive input by resistance R36 connections
Device U6 output end, reverse input end are grounded by resistance R38.A resistance R37 termination power, other end connection amplifier U5
Reverse input end.Electric capacity C15, resistance R12 are connected in parallel between amplifier U6 itself output end and reverse input end.Amplifier
U6 reverse input end is grounded by resistance R11.Amplifier U6 positive input is grounded by electric capacity C16, and the end is gone back simultaneously
The resistance R13 of photoelectric switching circuit is connected to, for reception signal.
The concrete structures of RF level sensitive circuits as shown in figure 9, by electric capacity C40, resistance R33, resistance R32, electric capacity C41,
Chip IC, electric capacity C42 and electric capacity C41 compositions.The pin 1 of chip IC connects signal acquisition circuit, pin 2 is connect by electric capacity C43
Ground, pin 3 are grounded, pin 4 is by the way that electric capacity C42 is grounded, pin 5 is grounded, pin 7 is sequentially connected in series resistance R32 and resistance R33 is followed by
Ground.Electric capacity C41 is connected in parallel on resistance R32 and resistance R33 both ends, and electric capacity C40 is connected in parallel on resistance R33 both ends, resistance R32 and resistance
MCU is connected between R33.
The concrete structure of one-level amplifying circuit is as shown in Figure 10, its mainly by electric capacity C19, electric capacity C20, electric capacity C21, put
Large chip IC1, inductance L2, electric capacity C23 and resistance R15 compositions.Amplification chip IC1 input is sequentially connected in series electric capacity C20, electric capacity
The middle part of the inductance coil of photoelectric switching circuit after C19.Amplification chip IC1 output end connection numerical-control attenuator, while the end
Power supply is connected after also passing sequentially through inductance L2, resistance R15.It is grounded between inductance L2, resistance R15 by electric capacity C23.
Numerical-control attenuator is mainly made up of AGC modular circuits and ATT modular circuits, and two modular structures are similar.One-level
After amplifying circuit is sequentially connected in series AGC modular circuits and ATT modular circuits, it is connected with second amplifying circuit.Two modules are used respectively
In the AGC control signals and ATT control signals that receive MCU transmissions.The concrete structure of AGC modular circuits, as shown in figure 11, AGC
Modular circuit mainly by electric capacity C25, diode four-tuple D1, inductance L3, electric capacity C24, electric capacity C44, resistance R16, electric capacity C27,
Resistance R20, resistance R17, resistance R18, resistance R19, electric capacity C22, resistance R21, resistance R22, electric capacity C28 and electric capacity C29 compositions.
Electric capacity C25 one end connection one-level amplifying circuit, other end connection diode four-tuple D1 pin 3, the pin 3 pass through resistance
R16 is grounded.The AGC control signal mouths that diode four-tuple D1 pin 2 passes through inductance L3 connections MCU.Inductance L3 and AGC is controlled
It is grounded between signal port by electric capacity C24.Diode four-tuple D1 pin 1 passes through electric capacity C44 connection ATT modular circuits, logical
Cross resistance R22 ground connection.Diode four-tuple D1 pin 4 is grounded by electric capacity C27, while the pin 4 is sequentially connected in series resistance
R20, resistance R18, resistance R17 are followed by power supply, are grounded between resistance R20 and resistance R18 by electric capacity C29, resistance R18 and resistance
It is grounded by resistance R19 between R17, is grounded between resistance R17 and power supply by electric capacity C22.Diode four-tuple D1 pin 5
It is grounded by electric capacity C28, while the pin 5 is connected between resistance R20, resistance R18 by resistance 21.
The concrete structure of ATT modular circuits, as shown in figure 4, mainly by diode four-tuple D2, inductance L4, electric capacity C31,
Electric capacity C35, resistance R23, electric capacity C32, resistance R27, resistance R24, resistance R25, resistance R26, electric capacity R28, resistance R29, electric capacity
C33 and electric capacity C34 compositions.Diode four-tuple D2 pin 3 connects electric capacity C44, and the pin 3 is grounded by resistance R23.Two poles
The ATT control signal mouths that pipe four-tuple D2 pin 2 passes through inductance L4 connections MCU.Lead between inductance L4 and ATT control signal mouth
Cross electric capacity C31 ground connection.Diode four-tuple D2 pin 1 connects by electric capacity C35 connections second amplifying circuit, by resistance R29
Ground.Diode four-tuple D2 pin 4 is grounded by electric capacity C32, while the pin 4 is sequentially connected in series resistance R27, resistance R26, electricity
Resistance R24 is followed by power supply, is grounded between resistance R27 and resistance R26 by electric capacity C33, passes through electricity between resistance R26 and resistance R24
R25 ground connection is hindered, is grounded between resistance R24 and power supply by electric capacity C22.Diode four-tuple D2 pin 5 is connect by electric capacity C34
Ground, while the pin 5 is connected between resistance R27, resistance R26 by resistance 28.
The concrete structure of second amplifying circuit is as shown in figure 12, and its structure is similar with one-level amplifying circuit, mainly by amplifying
Chip IC 2, inductance L5, electric capacity C36, electric capacity C30, resistance R30, resistance R31 compositions.Amplification chip IC2 input connection ATT
The electric capacity C35 of modular circuit, the input are grounded after being also sequentially connected in series resistance R30, electric capacity C36.Amplification chip IC2 output end
Connect signal acquisition circuit, while the end also pass sequentially through inductance L5, resistance R31 after connect power supply.Inductance L5, resistance R31 it
Between be grounded by electric capacity C36.It is grounded between resistance R31 and power supply by electric capacity C30.
The concrete structure of RF signal acquisition circuits is as shown in figure 13, and it is by electric capacity C37, chip CX, resistance R34, electric capacity
C39, electric capacity C38 are formed.Electric capacity C37 one end connection second amplifying circuit, other end connection chip CX input, chip CX
Output end pass through electric capacity C38 export RF radiofrequency signals.The IC of chip CX another output end connection RF level sensitive circuits
The pin 1 of chip.
The MCU of family expenses photoreceiver use MINI54ZDE models MCU, as shown in figure 14, also can use 8051, PIC,
Dynamic AGC, ATT function of the realizations such as AVR, Cortex-M0/M0+, Cortex-M3, Cortex-M4.
, it is necessary to build corresponding connection circuit, such as when sampling the MCU of MINI54ZDE models:MCU external clock input
Circuit, see Figure 15, crystal oscillation signal is provided by Y1;MCU reset reset circuit, is shown in Figure 16;MCU system input circuit, is shown in figure
17, the input circuit mainly uses ONU (i.e. optical network unit) MCU;MCU I2C circuits, are shown in Figure 18;MCU ADC signal
Input circuit, see Figure 19, the input circuit is mainly used in signal and the RF level detections that received optical power detection circuit is sent
The signal that circuit is sent;The earthed circuit of MCU ADC signal input interface, is shown in Figure 20.The OPTIC_AGC signal outputs of the MCU
Pin and RF_ATT signal output pins are connected with the AGC modular circuits and ATT modular circuits of numerical-control attenuator respectively.
The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, it is noted that all
All any modification, equivalent and improvement made within the spirit and principles in the present invention etc., it should be included in the guarantor of the present invention
Within the scope of shield.