CN209562647U - The single-ended camera signals processing circuit of highly resistance immunity - Google Patents

Abstract

A kind of single-ended camera signals processing circuit of highly resistance immunity, the one end resistor R1 connects output signal anode, the one end capacitor C2 and one end resistor R3 of camera, the resistor R1 other end connects output signal cathode, the one end capacitor C1 and one end resistor R2 of camera, capacitor C1 other end ground connection；The resistor R2 other end connects the capacitor C2 other end and the one end resistor R5, the resistor R5 other end connects the one end resistor R6 and the one end capacitor C4, the resistor R3 other end connects the one end resistor R4 and the one end capacitor C3, the resistor R4 other end is connected and is grounded with the resistor R6 other end, and the capacitor C3 other end, the capacitor C4 other end are separately connected video decoding chip signal sampling end positive and negative electrode.The utility model can effectively inhibit common mode interference existing for camera negative terminal and vehicle body electromagnetic interference, and at low cost, parameter regulation is simple and convenient, high reliablity, be suitable for automobile electronics.

Description

The single-ended camera signals processing circuit of highly resistance immunity

Technical field

The utility model relates to the Anti-Jamming Technique of electricity field more particularly to camera, especially a kind of highly resistance immunity Single-ended camera signals processing circuit.

Background technique

In the prior art, camera on automobile using more and more, and the harness network on automobile is complicated, electromagnetism ring Border is severe, and camera signals are highly susceptible to the arrangement of harness and the influence of electromagnetic interference, has picture water ripples occur often Or jitter phenomenon.Therefore the input signal processing circuit of common-path interference is required, to guarantee that image is shown normally.

Currently, common camera input lattice network have it is following several:

Single-ended camera inputs lattice network.Although program circuit is simple, anti-interference is poor, especially local When having common mode interference on line, display picture will appear water ripples.

Pseudo-differential camera inputs lattice network.The program is in schemeOn the basis of improve, solve ground wire Common mode interference problem, but work as Che Shangyou electromagnetic interference, especially when having BCI(Bulk Current Injection, Vehicular visual Backing system) when, picture will appear water ripples or tremble screen phenomenon.

Difference camera inputs lattice network.The program and schemeIt compares, display image quality is relatively clear, but When equally existing BCI, picture has water ripples or trembles screen phenomenon, and is only applicable to difference camera output type.

Dedicated integrated processing chip.With scheme, schemeAnd schemeIt compares, dedicated integrated processing chip Filtering and interference free performance have been improved, but its cost is also higher.

Utility model content

It can be avoided common mode present on camera ground wire the technical problem to be solved by the present invention is to provide one kind to do It disturbs and vehicle body electromagnetic interference, and the signal processing circuit that at low cost, high reliablity, stability are strong.

In order to solve the above-mentioned technical problem, the technical solution of the utility model is to provide a kind of single-ended camera of highly resistance immunity Signal processing circuit, it is characterised in that: including resistor R1, the one end the resistor R1 connects the output signal anode of camera CVBS+, the one end capacitor C2 and the one end resistor R3, the output signal cathode of the resistor R1 other end connection camera CVBS-, the one end capacitor C1 and the one end resistor R2, the capacitor C1 other end ground connection；The resistor R2 other end connects Connect the capacitor C2 other end and the one end resistor R5, described resistor R5 other end connection one end resistor R6 and capacitor The one end C4, resistor R3 other end connection one end resistor R4 and the one end capacitor C3, the resistor R4 other end and The resistor R6 other end connection and ground connection, the capacitor C3 other end connection video decoding chip signal sampling rectify pole AN1, the capacitor C4 other end connect video decoding chip signal sampling end cathode AN2.

Preferably, the resistor R1 is terminal coupling resistor, the resistance value of the resistor R1 and the output of camera Impedance is equal.

Preferably, the resistance value of the resistor R2 is equal to the parallel value of the output impedance of the resistor R1 and camera.

Preferably, the resistor R1 guarantees the defeated of camera for eliminating the signal reflex in camera cable Signal can be transmitted to rear stage circuit out.

Preferably, the capacitor C1 is filter condenser, for filtering out the output signal cathode CVBS- of the camera Grounding interference signal on end line.

Preferably, the resistor R2 is for keeping difference monitoring voltage equal, to eliminate the output letter of the camera Common-mode voltage interference on number cathode CVBS- end line.

Preferably, the capacitor C2 is used to absorb the output signal anode CVBS+ and the camera of the camera Output signal cathode CVBS- difference mode signal interference.

Preferably, the resistor R3 and resistor R4 forms potential-divider network, the resistor R5 and resistor R6 composition Potential-divider network, can be with to rear-class video decoding chip for dividing the signal of the output signal anode CVBS+ of the camera In the range of receiving, while transient suppression pulse voltage, electric current is reduced, rear-class video decoding chip is protected.

Preferably, the resistor R3, resistor R4, resistor R5, the resistor that resistor R6 is same error.

Preferably, the capacitor C3, capacitor C4 are AC decoupling capacitors, for eliminating the direct current of incoming video signal Bias voltage；Simultaneously when the output signal cathode CVBS- of the output signal anode CVBS+ of the camera or the camera are short When road is to cell voltage, " resistor R3, resistor R4 and capacitor C3 " or " resistor R5, resistor R6 and resistor C4 " energy It is enough to reduce the voltage and current for being input to next stage video decoding chip, effective protection video decoding chip.

Compared with prior art, the single-ended camera signals processing circuit of highly resistance immunity provided by the utility model has and has as follows Beneficial effect:

1, common mode interference existing for camera negative terminal can effectively be inhibited；

2, BCI differential mode vehicle body electromagnetic interference can effectively be inhibited；

3, it is designed using discrete component, at low cost, flexible design, parameter regulation is simple and convenient；

4, the component of automobile is selected, high reliablity, stability is strong, is suitable for automobile electronics.

Detailed description of the invention

Fig. 1 is the single-ended camera signals processing circuit schematic diagram of highly resistance immunity provided in this embodiment；

Fig. 2 is the single-ended camera signals processing circuit exemplary application map of highly resistance immunity provided in this embodiment.

Specific embodiment

Fig. 1 is the single-ended camera signals processing circuit schematic diagram of highly resistance immunity provided in this embodiment, the high interference immunity Property single-ended camera signals processing circuit include resistor R1 ~ R6, capacitor C1 ~ C4, the one end resistor R1 connects camera Output signal anode CVBS+, the one end capacitor C2 and the one end resistor R3, the resistor R1 other end connect the output letter of camera Number cathode CVBS-, the one end capacitor C1 and the one end resistor R2, capacitor C1 other end ground connection；The connection of the resistor R2 other end The capacitor C2 other end and the one end resistor R5, the resistor R5 other end connect the one end resistor R6 and the one end capacitor C4, electricity Resistance device R3 other end connection one end resistor R4 and the one end capacitor C3, the resistor R4 other end are connected with the resistor R6 other end And be grounded, the capacitor C3 other end connects video decoding chip signal sampling and rectifies pole AN1, and the capacitor C4 other end connects video Decoding chip signal sampling end cathode AN2.

Wherein, resistor R1 is terminal coupling resistor, and resistance value is equal with the external output impedance of camera.Due to list Hold the output impedance of camera frequently with 75 Ω, therefore in the present embodiment, R1 resistance value is also 75 Ω.The effect of resistor R1 be in order to The signal reflex in camera cable is eliminated, guarantees that the output signal of camera can be transmitted to rear stage circuit, is reduced Signal reflex loss, promotes efficiency of transmission.

Capacitor C1 is filter condenser, and the ground wire mainly filtered out on the output signal cathode CVBS- end line of camera is dry Disturb signal.

The resistance value of resistor R2 should be equal with the output impedance parallel value of resistor R1 and camera, selects in the present embodiment 37.5 Ω, effect is to keep difference monitoring voltage equal, effectively eliminates the common mode electricity at the end output signal cathode CVBS- of camera It press dry and disturbs.

Capacitor C2 can effectively absorb the output signal anode CVBS+ of camera and the output signal cathode of camera The difference mode signal of CVBS- interferes, and offsets except frequency is particularly evident greater than the interference signal of 1MHZ, can be effectively improved EMC BCI Interference.

Resistor R3 and resistor R4 forms potential-divider network, can be by the signal at the end output signal anode CVBS+ of camera In the range of partial pressure can be born to rear-class video decoding chip.Simultaneously electric current, protection can be reduced with transient suppression pulse voltage Rear-class video decoding chip.

Resistor R5 and resistor R6 also forms potential-divider network, acts on similar with resistor R3 and resistor R4.For up to To better display performance, image fault is avoided, resistor R3, resistor R4, resistor R5, resistor R6 will select same mistake The resistor of difference, and error rate is low as far as possible.

Capacitor C3, capacitor C4 are AC decoupling capacitors, can eliminate the DC offset voltage of incoming video signal.When When the output signal anode CVBS+ of camera or the output signal cathode CVBS- of camera are shorted to cell voltage, " resistor R3, resistor R4 and capacitor C3 " or " resistor R5, resistor R6 and resistor C4 " can reduce and be input to next stage video The voltage and current of decoding chip, effective protection video decoding chip.

It is illustrated in figure 2 the single-ended camera signals processing circuit exemplary application map of highly resistance immunity provided in this embodiment, is taken the photograph As output signal anode CVBS+, the cathode CVBS- of head are coupled with the positive and negative output end of camera Camara.Video decodes core Piece signal sampling end positive and negative electrode AN1, AN2 are respectively outputted to the positive and negative input terminal of video decoding chip Video decoder.R0 For the output impedance of camera.

Experiments have shown that the single-ended camera signals processing circuit of highly resistance immunity provided in this embodiment can effectively inhibit to image Common mode interference and BCI differential mode vehicle body electromagnetic interference existing for head negative terminal, parameter regulation is simple and convenient, high reliablity, and stability is strong.

The above, the only preferred embodiment of the utility model, it is in any form and substantive not to the utility model On limitation, it is noted that for those skilled in the art, in the premise for not departing from the utility model method Under, several improvement and supplement can be also made, these are improved and supplement also should be regarded as the protection scope of the utility model.It is all ripe Professional and technical personnel is known, in the case where not departing from the spirit and scope of the utility model, when using disclosed above Technology contents and the equivalent variations of a little variation, modification and evolution made, be the equivalent embodiment of the utility model；Together When, all substantial technologicals according to the utility model to the variation, modification and evolution of any equivalent variations made by above-described embodiment, In the range of still falling within the technical solution of the utility model.

Claims (10)

1. a kind of single-ended camera signals processing circuit of highly resistance immunity, it is characterised in that: including resistor R1, the resistor R1 One end connects output signal anode CVBS+, the one end capacitor C2 and one end resistor R3 of camera, and the resistor R1 is another Output signal cathode CVBS-, the one end capacitor C1 and one end resistor R2 of end connection camera, the capacitor C1 other end Ground connection；The resistor R2 other end connects the capacitor C2 other end and the one end resistor R5, the resistor R5 are another End connection one end resistor R6 and the one end capacitor C4, described resistor R3 other end connection one end resistor R4 and capacitor C3 One end, the resistor R4 other end are connected and are grounded with the resistor R6 other end, the capacitor C3 other end connection Video decoding chip signal sampling rectifies pole AN1, and capacitor C4 other end connection video decoding chip signal sampling end is negative Pole AN2.

2. a kind of single-ended camera signals processing circuit of highly resistance immunity as described in claim 1, it is characterised in that: the resistance Device R1 is terminal coupling resistor, and the resistance value of the resistor R1 is equal with the output impedance of camera.

3. a kind of single-ended camera signals processing circuit of highly resistance immunity as described in claim 1, it is characterised in that: the resistance The resistance value of device R2 is equal to the parallel value of the output impedance of the resistor R1 and camera.

4. a kind of single-ended camera signals processing circuit of highly resistance immunity as described in claim 1, it is characterised in that: the resistance Device R1 guarantees that the output signal of camera can be transmitted to rear stage electricity for eliminating the signal reflex in camera cable Road.

5. a kind of single-ended camera signals processing circuit of highly resistance immunity as described in claim 1, it is characterised in that: the capacitor Device C1 is filter condenser, the grounding interference signal on output signal cathode CVBS- end line for filtering out the camera.

6. a kind of single-ended camera signals processing circuit of highly resistance immunity as described in claim 1, it is characterised in that: the resistance Device R2 is for keeping difference monitoring voltage equal, to eliminate the common mode on the output signal cathode CVBS- end line of the camera Voltage disturbance.

7. a kind of single-ended camera signals processing circuit of highly resistance immunity as described in claim 1, it is characterised in that: the capacitor Device C2 is used to absorb the difference of the output signal anode CVBS+ of the camera and the output signal cathode CVBS- of the camera Mould signal interference.

8. a kind of single-ended camera signals processing circuit of highly resistance immunity as described in claim 1, it is characterised in that: the resistance Device R3 and resistor R4 forms potential-divider network, and the resistor R5 and resistor R6 form potential-divider network, be used for the camera shooting The signal of the output signal anode CVBS+ of head is divided to rear-class video decoding chip in the range of can bearing, while inhibiting wink State pulse voltage reduces electric current, protects rear-class video decoding chip.

9. a kind of single-ended camera signals processing circuit of highly resistance immunity as described in claim 1, it is characterised in that: the resistance Device R3, resistor R4, resistor R5, the resistor that resistor R6 is same error.

10. a kind of single-ended camera signals processing circuit of highly resistance immunity as described in claim 1, it is characterised in that: the electricity Container C3, capacitor C4 are AC decoupling capacitors, for eliminating the DC offset voltage of incoming video signal；It is taken the photograph simultaneously when described When being shorted to cell voltage as the output signal anode CVBS+ of head or the output signal cathode CVBS- of the camera, " resistance Device R3, resistor R4 and capacitor C3 " or " resistor R5, resistor R6 and resistor C4 " reduction are input to next stage video solution The voltage and current of code chip, effective protection video decoding chip.