Embodiment
Below in conjunction with the drawings and specific embodiments, the present invention is described in detail.
Embodiment
The invention provides a kind of ATT control method of management type family expenses optical receiver, for management type family expenses optical receiver.As shown in Figure 1, it is primarily of connector, photoelectric switching circuit (PIN w/oWDM), luminous power testing circuit, MCU, two amplifier, numerical-control attenuator, RF level sensitive circuit, AGC signal circuit, ATT signal circuit and signal acquisition circuit compositions for the structure of whole management type family expenses optical receiver.
Wherein luminous power testing circuit, MCU and AGC signal circuit composition AGC control circuit, the input of luminous power testing circuit is connected with photoelectric switching circuit, output is connected with the optical power signals input port of MCU.The AGC control signal output of MCU is connected with the AGC control end of numerical-control attenuator by AGC signal circuit.
Wherein RF level sensitive circuit, MCU and ATT signal circuit composition ATT control circuit, the input of RF level sensitive circuit is connected with signal acquisition circuit, and the output of RF level sensitive circuit is connected with the RF sampled level input port of MCU.The ATT control signal output of MCU is connected with the ATT control end of numerical-control attenuator by ATT signal circuit.
When utilizing ATT control circuit to carry out ATT control, its method comprises the following steps:
(1) MCU utilizes RF level sensitive circuit to sample the RF radiofrequency signal that current optical receiver exports, and obtains RF RF signal values;
(2) receive the attenuation of the current needs that user is arranged, and table look-up according to this attenuation, find ATT control voltage value;
(3) according to the control voltage of this ATT control voltage value adjustment two-stage amplifier, realize ATT and control.
The table looked in step (2) is through test and just obtains, and then to be stored by this table for MCU reading.When making this table, we test 50 amplifier IC, and get its mean value and realize ATT function, the table obtained is:
After photoelectric switching circuit converts 1550nm or 1310nm light signal to the signal of telecommunication, send to one-level amplifying circuit, signal after one-level is amplified sends to numerical-control attenuator, and the signal after decay after secondary amplifies, becomes required radio frequency rf signal and exports again.When the first order is amplified, sampled (mainly luminous power testing circuit realizes) by the luminous power of MCU to current input, draw accurate Output optical power, and adjust the control voltage of first order amplifier by the size of input optical power, be i.e. AGC function; When secondary amplifies, sampled (mainly RF level sensitive circuit realizes) by the radio frequency rf signal of MCU to current output, and adjust the control voltage of second level amplifier according to the attenuation of setting, i.e. ATT function.
Whole management type family expenses optical receiver can realize carrying out compatibility with the ONU of other producers, receiver and ONU are arranged in a compact shell, realize unified fiber entering household scheme, simultaneously radio and TV operator can the running parameter (input optical power, output level, optical receiver working temperature, and the output level that can realize remote adjustment receiver according to the operating state that receiver is real-time) of real time inspection family expenses optical receiver.Optical receiver realizes the mutual of optical receiver module and other modules by connector, and its interactive information mode has following 3 kinds of modes: UART, I2C and SPI.
Below the composition of whole management type family expenses optical receiver is described in detail:
The present embodiment provides a kind of AGC signal circuit, and as shown in Figure 2, it forms primarily of 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.One end of resistance R1 connects power supply, the other end successively by the positive input of resistance R2, resistance R3 connection amplifier U1.By electric capacity C1 ground connection between resistance R2, resistance R3.The positive input of amplifier U1 is by electric capacity C2 ground connection.Between the reverse input end that resistance R4 and electric capacity C3 is connected in parallel on amplifier U1 self and output.The reverse input end of amplifier U1 is by resistance R5 ground connection.The output of amplifier U1 connects the positive input of amplifier U2.The reverse input end of amplifier U2 is connected with its output.By electric capacity C4 ground connection between the output of amplifier U1 and the positive input of amplifier U2.Electric capacity C4 adopts variable capacitance.Connect the AGC control signal output of MCU between resistance R1 and resistance R2, the AGC control end of the output numerical-control attenuator of amplifier U2 connects.
How to reduce ripple in the MCU signals transmission that AGC signal circuit mainly solves, improve the problem of the responsiveness that DAC exports.Be used for the occasion of DA conversion at PWM, rc filter circuit is the important step of relation conversion effect.By RC discharge and recharge constant, we roughly can calculate the discharge and recharge frequency of capacitance-resistance link, have been generally and have obtained desirable filter effect, and this frequency will much smaller than the output frequency of PWM (being less than 1/4th).Generally, when the less R of C is larger, the voltage loss that DA changes out is very little, but ripple is but very large; When the larger R of C is less, the voltage loss that DA changes out is very large, but ripple is relatively little.So when needing to carry out must using less filter capacitor when the very high accurate DA of Linearity changes, and avoid using electrolysis class electric capacity as far as possible.And export to obtain stronger signal, also must add the high performance voltage follow of one-level after RC inertial element, the place then exported at follower adds the electrochemical capacitor of a filtering, for the ripple of level and smooth RC inertial element.But this not enough, because may containing more AC harmonic composition in output voltage at this moment, if dealt with improperly, follower is self-excitation likely.Solution be exactly use one little remove lotus root electric capacity.And here electric capacity placement order must be electrochemical capacitor front, go lotus root electric capacity rear! If output voltage precision and Linearity less demanding, but require but very high to ripple, or when this voltage compare is fixed, the filtering combination that electric capacity can be used larger.Because although the DC losses of bulky capacitor is comparatively large, we can meet the requirements of output voltage by regulating PWM duty ratio, or realize the output of accurate fixed voltage by the feedback of one-level AD conversion.Just still will add voltage order one follower here, so that rear class Acquisition Circuit uses, and AD collection point is placed on follower output.
In actual use, for the ease of circuit collocation, the resistance of second-order low-pass filter and capacitance selection are onesize by we, and therefore second-order low-pass filter is as follows by frequency computation part formula:
Oscilloscope is used to test this AGC signal circuit, its oscilloscope test circuit figure as shown in figure 21, oscilloscope is used to test the result that obtains as shown in figure 22, as seen from the figure, this circuit from power on to 95% duty ratio, spent time is 116.923ms, meets our range of application completely.
The present embodiment provides a kind of ATT signal circuit, this transmission circuit and AGC transmission circuit similar, as shown in Figure 3, ATT signal circuit is made up of 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 its concrete structure.One end of resistance R6 connects power supply, the other end successively by the positive input of resistance R7, resistance R8 connection amplifier U3.By electric capacity C5 ground connection between resistance R7, resistance R8.The positive input of amplifier U3 is by electric capacity C6 ground connection.Between the reverse input end that resistance R9 and electric capacity C7 is connected in parallel on amplifier U3 self and output.The reverse input end of amplifier U3 is by resistance R10 ground connection.The output of amplifier U3 connects the positive input of amplifier U4.The reverse input end of amplifier U4 is connected with its output, by electric capacity C8 ground connection between the output of described amplifier U3 and the positive input of amplifier U4.Electric capacity C8 is variable capacitance.Connect the ATT control signal output of MCU between resistance R6 and resistance R7, the ATT control end of the output numerical-control attenuator of amplifier U4 connects.Due to the structural similarity with AGC signal circuit, thus this circuit can play the effect of AGC signal circuit equally.
As shown in Figure 4, it forms primarily of power-switching circuit, system interface, photoelectric switching circuit, luminous power testing circuit, RF level sensitive circuit figure, one-level amplifying circuit, numerical-control attenuator, second amplifying circuit and RF signal acquisition circuit the circuit structure of whole management type family expenses optical receiver removing MCU part.
As shown in Figure 5, it forms primarily of electric capacity C9, electric capacity C10, electric capacity C11, electric capacity C12, electric capacity C13, electric capacity C14 the concrete structure of power-switching circuit.
As shown in Figure 6, the peripheral circuit of its MCU chip primarily of ONU (i.e. optical network unit) and each pin is formed the concrete structure of system interface.
As shown in Figure 7, it forms primarily of electric capacity C17, resistance capacitance C18, resistance R13, resistance R14, inductance L 1, PIN photodiode and inductance coil the concrete structure of photoelectric switching circuit.The negative pole of PIN photodiode is both by electric capacity C17 ground connection, and direct power supply again, its positive pole connects one end of inductance coil by inductance L 1.The other end of inductance coil connects luminous power testing circuit by resistance R13, and this end is simultaneously also respectively by electric capacity C18, resistance R14 ground connection.The middle part of inductance coil connects one-level amplifying circuit.
As shown in Figure 8, it forms primarily of resistance R35, amplifier U5, resistance R36, resistance R37, resistance R38, resistance R12, electric capacity C15, resistance R11, electric capacity C16 and amplifier U6 the concrete structure of luminous power testing circuit.The output of amplifier U5 connects the output of amplifier U6, reverse input end by resistance R38 ground connection by the OPTIC_ALM interface clock signal of resistance R35 connected system interface, positive input by resistance R36.One termination power of resistance R37, the other end connect the reverse input end of amplifier U5.Between the output that electric capacity C15, resistance R12 are connected in parallel on amplifier U6 self and reverse input end.The reverse input end of amplifier U6 is by resistance R11 ground connection.The positive input of amplifier U6 is by electric capacity C16 ground connection, and this end is also connected to the resistance R13 of photoelectric switching circuit simultaneously, for Received signal strength.
The concrete structure of RF level sensitive circuit as shown in Figure 9, is made up of electric capacity C40, resistance R33, resistance R32, electric capacity C41, chip IC, electric capacity C42 and electric capacity C41.The pin 1 connection signal Acquisition Circuit of chip IC, pin 2 pass through electric capacity C43 ground connection, pin 3 ground connection, pin 4 by ground connection after electric capacity C42 ground connection, pin 5 ground connection, pin 7 successively series resistance R32 and resistance R33.Electric capacity C41 is connected in parallel on the two ends of resistance R32 and resistance R33, and electric capacity C40 is connected in parallel on resistance R33 two ends, is connected MCU between resistance R32 with resistance R33.
As shown in Figure 10, it forms primarily of electric capacity C19, electric capacity C20, electric capacity C21, amplification chip IC1, inductance L 2, electric capacity C23 and resistance R15 the concrete structure of one-level amplifying circuit.The input of amplification chip IC1 is the middle part of the inductance coil of photoelectric switching circuit after serial capacitance C20, electric capacity C19 successively.The output of amplification chip IC1 connects numerical-control attenuator, and this end is also successively by connecting power supply after inductance L 2, resistance R15 simultaneously.By electric capacity C23 ground connection between inductance L 2, resistance R15.
Numerical-control attenuator is primarily of AGC modular circuit and ATT modular circuit composition, and two modular structures are similar.One-level amplifying circuit is connected with second amplifying circuit after being connected in series AGC modular circuit and ATT modular circuit successively.Two modules are respectively used to the AGC control signal and the ATT control signal that receive MCU transmission.The concrete structure of AGC modular circuit, as shown in figure 11, AGC modular circuit forms primarily of electric capacity C25, diode four-tuple D1, inductance L 3, 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.The pin 3 that one end connects one-level amplifying circuit, the other end connects diode four-tuple D1 of electric capacity C25, this pin 3 is by resistance R16 ground connection.The pin 2 of diode four-tuple D1 connects the AGC control signal mouth of MCU by inductance L 3.By electric capacity C24 ground connection between inductance L 3 and AGC control signal mouth.The pin 1 of diode four-tuple D1 connects ATT modular circuit, by resistance R22 ground connection by electric capacity C44.The pin 4 of diode four-tuple D1 is by electric capacity C27 ground connection, this pin 4 connects power supply after series resistance R20, resistance R18, resistance R17 successively simultaneously, by electric capacity C29 ground connection between resistance R20 and resistance R18, by resistance R19 ground connection between resistance R18 and resistance R17, by electric capacity C22 ground connection between resistance R17 and power supply.The pin 5 of diode four-tuple D1 is by electric capacity C28 ground connection, and this pin 5 is connected between resistance R20, resistance R18 by resistance 21 simultaneously.
The concrete structure of ATT modular circuit, as shown in Figure 4, form primarily of diode four-tuple D2, inductance L 4, 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.The pin 3 of diode four-tuple D2 connects electric capacity C44, and this pin 3 is by resistance R23 ground connection.The pin 2 of diode four-tuple D2 connects the ATT control signal mouth of MCU by inductance L 4.By electric capacity C31 ground connection between inductance L 4 and ATT control signal mouth.The pin 1 of diode four-tuple D2 connects second amplifying circuit, by resistance R29 ground connection by electric capacity C35.The pin 4 of diode four-tuple D2 is by electric capacity C32 ground connection, this pin 4 connects power supply after series resistance R27, resistance R26, resistance R24 successively simultaneously, by electric capacity C33 ground connection between resistance R27 and resistance R26, by resistance R25 ground connection between resistance R26 and resistance R24, by electric capacity C22 ground connection between resistance R24 and power supply.The pin 5 of diode four-tuple D2 is by electric capacity C34 ground connection, and this pin 5 is connected between resistance R27, resistance R26 by resistance 28 simultaneously.
The concrete structure of second amplifying circuit as shown in figure 12, its structure and one-level amplifying circuit similar, form primarily of amplification chip IC2, inductance L 5, electric capacity C36, electric capacity C30, resistance R30, resistance R31.The input of amplification chip IC2 connects the electric capacity C35 of ATT modular circuit, this input also ground connection after series resistor R30, electric capacity C36 successively.The output connection signal Acquisition Circuit of amplification chip IC2, this end is also successively by connecting power supply after inductance L 5, resistance R31 simultaneously.By electric capacity C36 ground connection between inductance L 5, resistance R31.By electric capacity C30 ground connection between resistance R31 and power supply.
As shown in figure 13, it is made up of electric capacity C37, chip CX, resistance R34, electric capacity C39, electric capacity C38 the concrete structure of RF signal acquisition circuit.The input that one end connects second amplifying circuit, the other end connects chip CX of electric capacity C37, the output of chip CX exports RF radiofrequency signal by electric capacity C38.Another output of chip CX connects the pin 1 of the IC chip of RF level sensitive circuit.
The MCU of family expenses optical receiver adopts the MCU of MINI54ZDE model, as shown in figure 14, also can adopt 8051, PIC, AVR, Cortex-M0/M0+, and Cortex-M3, Cortex-M4 etc. realize dynamic AGC, ATT function.
During the MCU of sampling MINI54ZDE model, need to build corresponding connecting circuit, as: the external clock input circuit of MCU, see Figure 15, provide crystal oscillation signal by Y1; The reset reset circuit of MCU, is shown in Figure 16; The system input circuit of MCU, is shown in Figure 17, and this input circuit mainly adopts the MCU of ONU (i.e. optical network unit); The I2C circuit of MCU, is shown in Figure 18; The ADC signal input circuit of MCU, is shown in Figure 19, and this input circuit is mainly used in the signal of received optical power testing circuit transmission and the signal of RF level sensitive circuit transmission; The earthed circuit of the ADC signal input interface of MCU, is shown in Figure 20.The OPTIC_AGC signal output pin of this MCU and RF_ATT signal output pin are connected with the AGC modular circuit of numerical-control attenuator and ATT modular circuit respectively.
The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, it should be pointed out that all any amendments done within the spirit and principles in the present invention, equivalent replacement and improvement etc., all should be included within protection scope of the present invention.