CN212305505U - Video signal amplifying circuit for talkback video doorbell - Google Patents
Video signal amplifying circuit for talkback video doorbell Download PDFInfo
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- CN212305505U CN212305505U CN202021381288.9U CN202021381288U CN212305505U CN 212305505 U CN212305505 U CN 212305505U CN 202021381288 U CN202021381288 U CN 202021381288U CN 212305505 U CN212305505 U CN 212305505U
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Abstract
The utility model relates to a video signal amplifier circuit for talkback video doorbell. The audio signal input terminal AOP is connected with a preceding stage amplifying circuit, the preceding stage amplifying circuit is connected with a subsequent stage amplifying circuit, the subsequent stage amplifying circuit comprises an operational amplifier U2, the inverting input terminal of the operational amplifier U2 is connected with the preceding stage amplifying circuit and the image signal output terminal CAM _ OUT respectively through a resistor R6, the image signal output terminal CAM _ OUT is connected with the operational amplifier U2 through an image signal voltage division circuit, the output terminal of the operational amplifier U2 is connected with the signal output terminal AOUT through a resistor R13 in sequence, and the output terminal of the resistor R13 is grounded through an electronic switch tube. The utility model controls the on-off of the whole video signal amplifying circuit by arranging the electronic switch tube, and the audio signal and the image signal are synchronously output; avoid the audio-only and image-free phenomena.
Description
Technical Field
The utility model relates to an intercom doorbell technical field especially relates to a video signal amplifier circuit for intercom video doorbell.
Background
With the continuous development of electronic technology, the talkback video technology is also continuously developed, a traditional doorbell and talkback video are combined to form a talkback video doorbell in the market at present, the talkback video doorbell is arranged outside a door, when a person visits, the person can be prompted through the doorbell, and then an owner can start the audio or/and video of the talkback video for confirmation; in the process, in order to clearly acquire the sound signal of the visitor, a video signal amplifying circuit is generally arranged to amplify the audio signal, and because an image signal exists at the same time, the audio signal and the image signal are generally modulated to form a video signal in order to facilitate signal processing, and the image signal may be jammed in the transmission process, so that the phenomenon that the sound exists and the image is fixed is often found, which brings confusion to the user; causing inconvenience in use.
Disclosure of Invention
An object of the utility model is to prior art not enough, provide a video signal amplifier circuit for talkbacking video doorbell, this video signal amplifier circuit stops external output when not having image signal, avoids appearing the sound and the unchangeable phenomenon of image takes place.
A video signal amplifying circuit for a talkback video doorbell comprises an audio signal input end AOP, an image signal output end CAM _ OUT and a signal output end AOUT, wherein the audio signal input end AOP is connected with a preceding stage amplifying circuit, the preceding stage amplifying circuit is connected with a subsequent stage amplifying circuit, the subsequent stage amplifying circuit comprises an operational amplifier U2, the inverting input end of the operational amplifier U2 is respectively connected with the output end of the preceding stage amplifying circuit and the image signal output end CAM _ OUT through a resistor R6, the image signal output end CAM _ OUT is connected with an image signal voltage dividing circuit, the middle potential point of the image signal voltage dividing circuit is connected with the non-inverting input end of the operational amplifier U2 through a resistor R10, the output end of the operational amplifier U2 is connected with the signal output end AOUT through a resistor R13 and a capacitor C11 in sequence, and the output end of the operational amplifier U2 is connected with a capacitor C9 and a capacitor C86, The resistor R12 is connected with the inverting input end of the operational amplifier U2; the output end of the resistor R13 is grounded through an electronic switch tube.
Furthermore, the pre-stage amplifying circuit comprises an operational amplifier U1, an inverting input end of the operational amplifier U1 is connected with an audio signal input end AOP sequentially through a resistor R2, a capacitor C2 and a capacitor C1, and an output end of a capacitor C1 is grounded through a resistor R1; the non-inverting input end of the operational amplifier U1 is connected with a reference potential, and a resistor R5 and a capacitor C4 which are connected in parallel are connected between the input end and the inverting input end of the operational amplifier U1.
Furthermore, a non-inverting input end of the operational amplifier U1 is connected with a front voltage division circuit, the front voltage division circuit comprises a resistor R3 and a resistor R4 which are connected in series, an input end of the resistor R3 is connected with the power supply ADD, an output end of the resistor R4 is grounded, and an input end of the resistor R4 is connected with a non-inverting input end of the operational amplifier U1.
Preferably, the non-inverting input of the operational amplifier U1 is grounded through a capacitor C3.
Further, the image signal output terminal CAM _ OUT is connected to the resistor R6 through the capacitor C6 and the resistor R7 in this order.
Further, a capacitor C8 and a resistor R11 which are sequentially connected in series are arranged between the resistor R6 and the inverting input end of the operational amplifier U2.
Further, the image signal voltage division circuit comprises a resistor R8 and a resistor R14 which are connected in series, wherein the resistor R8 is connected with the output end of the capacitor C6, and the resistor R14 is grounded.
Further, the resistor R14 is connected in parallel with the capacitor C7 and the resistor R9.
Further, the electronic switch tube is a transistor U3.
The utility model has the advantages that: the utility model controls the on-off of the whole video signal amplifying circuit by arranging the electronic switch tube, so that the audio signal and the image signal are synchronously output; avoid the audio-only and image-free phenomena.
Drawings
Fig. 1 is a circuit diagram of the present embodiment.
Detailed Description
The following detailed description of the present invention is made with reference to the accompanying drawings. As shown in fig. 1.
Example 1: a video signal amplifying circuit for a talkback video doorbell comprises an audio signal input end AOP, an image signal output end CAM _ OUT and a signal output end AOUT, wherein the audio signal input end AOP is connected with a preceding stage amplifying circuit, the preceding stage amplifying circuit is connected with a subsequent stage amplifying circuit, the subsequent stage amplifying circuit comprises an operational amplifier U2, the inverting input end of the operational amplifier U2 is respectively connected with the output end of the preceding stage amplifying circuit and the image signal output end CAM _ OUT through a resistor R6, the image signal output end CAM _ OUT is connected with an image signal voltage dividing circuit, the middle potential point of the image signal voltage dividing circuit is connected with the non-inverting input end of the operational amplifier U2 through a resistor R10, the output end of the operational amplifier U2 is connected with the signal output end AOUT through a resistor R13 and a capacitor C11 in sequence, and the output end of the operational amplifier U2 is connected with a capacitor C9 and a capacitor C86, The resistor R12 is connected with the inverting input end of the operational amplifier U2; the output end of the resistor R13 is grounded through an electronic switching tube, the control end of the electronic switching tube is connected with a control chip (not shown in the figure), when an image signal is available, the control chip controls the electronic switching tube to be turned off, otherwise, the electronic switching tube is turned on.
When the technical scheme works, the control end of the electronic switching tube is connected with the control chip, and the control chip controls the on-off of the electronic switching tube according to the existence of the image signal; after the audio signal is input through an audio signal input end AOP, the audio signal is amplified through a preceding stage amplifying circuit; the amplified audio signal and the received image signal are amplified and modulated in a post-stage amplifying circuit, and finally are output (output to a demodulation circuit) through a resistor R13, a capacitor C11 and an output end AOUT; when the image signal transmission fails, the control chip sends a control signal to the electronic switching tube, the electronic switching tube is switched on, the resistor R13 is directly grounded, and the audio signal is not output externally. Under normal conditions, an image signal exists, and the control chip always controls the electronic switching tube to be cut off. The control chip can control the IC or the processor, and send different control signals to the electronic switching tube by detecting the image signal, which is not described in detail in the prior art.
Furthermore, the pre-stage amplifying circuit comprises an operational amplifier U1, an inverting input end of the operational amplifier U1 is connected with an audio signal input end AOP sequentially through a resistor R2, a capacitor C2 and a capacitor C1, and an output end of a capacitor C1 is grounded through a resistor R1; the non-inverting input end of the operational amplifier U1 is connected with a reference potential, and a resistor R5 and a capacitor C4 which are connected in parallel are connected between the input end and the inverting input end of the operational amplifier U1.
In the technical scheme, a preceding stage amplifying circuit is set as an operational amplifier, and an audio signal is amplified through an operational amplifier U1; the signal amplification is stable. Meanwhile, the capacitor C1 and the resistor R1 form an RC filter circuit for filtering the input audio signal.
Furthermore, a non-inverting input end of the operational amplifier U1 is connected with a front voltage division circuit, the front voltage division circuit comprises a resistor R3 and a resistor R4 which are connected in series, an input end of the resistor R3 is connected with the power supply ADD, an output end of the resistor R4 is grounded, and an input end of the resistor R4 is connected with a non-inverting input end of the operational amplifier U1.
The reference potential is provided for the operational amplifier U1 through the voltage division of the resistor R3 and the resistor R4.
Preferably, the non-inverting input of the operational amplifier U1 is grounded through a capacitor C3.
The capacitor C3 functions as a filtering operation for stabilizing the reference potential.
Further, the image signal output terminal CAM _ OUT is connected to the resistor R6 through the capacitor C6 and the resistor R7 in this order.
The resistor R7 and the capacitor C6 are used for filtering the image signals.
Further, a capacitor C8 and a resistor R11 which are sequentially connected in series are arranged between the resistor R6 and the inverting input end of the operational amplifier U2.
The capacitor C8 and the resistor R11 form a filter circuit for filtering the coupled audio signal and image signal.
Further, the image signal voltage division circuit comprises a resistor R8 and a resistor R14 which are connected in series, wherein the resistor R8 is connected with the output end of the capacitor C6, and the resistor R14 is grounded.
The image signal voltage division circuit adopts series resistors to divide voltage, and the circuit is simple.
Further, the resistor R14 is connected in parallel with the capacitor C7 and the resistor R9.
The capacitor C7 and the resistor R9 are connected in parallel to form a filter circuit for filtering the image signal.
Further, the electronic switch tube is a transistor U3.
In specific implementation, the base of the transistor U3 is connected to the control chip for receiving a control signal, the collector of the transistor U3 is connected to the output terminal of the resistor R13 through the capacitor C10, and the emitter of the transistor U3 is grounded. When an image signal exists, the control chip sends a low level to the triode, otherwise, the control chip is a high level.
The above description is only a preferred embodiment of the present invention, and for those skilled in the art, there are variations on the detailed description and the application scope according to the idea of the present invention, and the content of the present description should not be interpreted as a limitation to the present invention.
Claims (9)
1. A video signal amplifying circuit for a talkback video doorbell comprises an audio signal input end AOP, an image signal output end CAM _ OUT and a signal output end AOUT, wherein the audio signal input end AOP is connected with a preceding stage amplifying circuit, the preceding stage amplifying circuit is connected with a subsequent stage amplifying circuit, the subsequent stage amplifying circuit comprises an operational amplifier U2, the inverting input end of the operational amplifier U2 is respectively connected with the output end of the preceding stage amplifying circuit and the image signal output end CAM _ OUT through a resistor R6, the image signal output end CAM _ OUT is connected with an image signal voltage dividing circuit, the middle potential point of the image signal voltage dividing circuit is connected with the non-inverting input end of the operational amplifier U2 through a resistor R10, the output end of the operational amplifier U2 is connected with the signal output end AOUT through a resistor R13 and a capacitor C11 in sequence, and the output end of the operational amplifier U2 is connected with a capacitor C9 and a capacitor C86, The resistor R12 is connected with the inverting input end of the operational amplifier U2; the method is characterized in that: the output end of the resistor R13 is grounded through an electronic switch tube.
2. A video signal amplification circuit for a intercom video doorbell as described in claim 1, wherein: the pre-stage amplifying circuit comprises an operational amplifier U1, an inverting input end of an operational amplifier U1 is connected with an audio signal input end AOP sequentially through a resistor R2, a capacitor C2 and a capacitor C1, and an output end of a capacitor C1 is grounded through a resistor R1; the non-inverting input end of the operational amplifier U1 is connected with a reference potential, and a resistor R5 and a capacitor C4 which are connected in parallel are connected between the input end and the inverting input end of the operational amplifier U1.
3. A video signal amplification circuit for a intercom video doorbell as described in claim 2, wherein: the non-inverting input end of the operational amplifier U1 is connected with a front voltage division circuit, the front voltage division circuit comprises a resistor R3 and a resistor R4 which are connected in series, the input end of the resistor R3 is connected with a power supply ADD, the output end of the resistor R4 is grounded, and the input end of the resistor R4 is connected with the non-inverting input end of the operational amplifier U1.
4. A video signal amplification circuit for a intercom video doorbell as described in claim 3, wherein: the non-inverting input of the operational amplifier U1 is grounded through a capacitor C3.
5. A video signal amplification circuit for a intercom video doorbell as described in claim 1, wherein: the image signal output terminal CAM _ OUT is connected to the resistor R6 through the capacitor C6 and the resistor R7 in this order.
6. The video signal amplification circuit for a intercom video doorbell of claim 5, further comprising: and a capacitor C8 and a resistor R11 which are sequentially connected in series are arranged between the resistor R6 and the inverting input end of the operational amplifier U2.
7. The video signal amplification circuit for a intercom video doorbell of claim 5, further comprising: the image signal voltage division circuit comprises a resistor R8 and a resistor R14 which are connected in series, wherein the resistor R8 is connected with the output end of a capacitor C6, and the resistor R14 is grounded.
8. The video signal amplification circuit for a intercom video doorbell of claim 7, further comprising: the resistor R14 is connected in parallel with a capacitor C7 and a resistor R9.
9. A video signal amplification circuit for a intercom video doorbell as described in claim 1, wherein: the electronic switch tube is a triode U3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021381288.9U CN212305505U (en) | 2020-07-14 | 2020-07-14 | Video signal amplifying circuit for talkback video doorbell |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021381288.9U CN212305505U (en) | 2020-07-14 | 2020-07-14 | Video signal amplifying circuit for talkback video doorbell |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN212305505U true CN212305505U (en) | 2021-01-05 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202021381288.9U Active CN212305505U (en) | 2020-07-14 | 2020-07-14 | Video signal amplifying circuit for talkback video doorbell |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN212305505U (en) |
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2020
- 2020-07-14 CN CN202021381288.9U patent/CN212305505U/en active Active
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