CN209787164U

CN209787164U - Novel campus security protection intercom system

Info

Publication number: CN209787164U
Application number: CN201920516239.2U
Authority: CN
Inventors: 苏文彬
Original assignee: FUJIAN HUADA DIGITAL TECHNOLOGY Co Ltd
Current assignee: FUJIAN HUADA DIGITAL TECHNOLOGY Co Ltd
Priority date: 2019-04-16
Filing date: 2019-04-16
Publication date: 2019-12-13
Anticipated expiration: 2029-04-16

Abstract

The utility model relates to a novel campus security protection intercom system, which comprises an interphone, wherein the interphone comprises an antenna, an RF module, a microprocessor, a key module, an A/D module, a D/A module, a loudspeaker and a microphone, and all circuit modules are connected in a matching way; the interphone also comprises an audio detection circuit and an automatic frequency modulation circuit; the automatic frequency modulation circuit comprises a voltage-controlled oscillator, a first potentiometer, a second potentiometer, a third resistor, a fourth resistor and a crystal resonator, an audio detection circuit is electrically connected with a loudspeaker, the audio detection circuit is grounded through the voltage-controlled oscillator, the first potentiometer and the third resistor in sequence, a control end of the first potentiometer is connected with a first end of the fourth resistor, a control end of the second potentiometer and the crystal resonator are respectively and electrically connected with a second end of the fourth resistor, a first end of the second potentiometer is grounded, and a second end of the second potentiometer is electrically connected with a microprocessor. The utility model discloses can carry out frequency control automatically, adjust the rate of accuracy height.

Description

Novel campus security protection intercom system

Technical Field

The utility model relates to a security protection control technical field especially relates to a novel campus security protection intercom system.

Background

The intercom system is an important component of security protection, and the intercom system generally adopts an intercom to carry out instant messaging, and the intercom provides one-to-one and one-to-many communication modes, so that the intercom system has the advantages of being simple to operate and more convenient to communicate. The intercom often needs to carry out the frequency modulation when using, and the commonly used frequency modulation mode is: direct frequency modulation and indirect frequency modulation. Direct modulation generally uses a modulation voltage to directly control the oscillation frequency of an oscillator, so that the oscillation frequency f (t) is changed according to the rule of the modulation voltage. In the LC oscillator, the varactor is adopted to realize direct frequency modulation, the circuit is simple, the frequency modulation circuit is one of the most widely adopted frequency modulation circuits at present, the maximum frequency deviation can be obtained under the requirement of realizing linear frequency modulation, but the defect is that the frequency stability is poor, and frequency stabilization measures or crystal oscillation modulation are required in many occasions; thus, two-point modulation is extended, one audio frequency is used for modulating the varactor, and the other audio frequency is used for modulating the reference crystal oscillator. The indirect modulation is generally that a modulation signal is integrated, then a carrier wave is subjected to phase modulation, and during the indirect modulation, a modulator and an oscillator are separated, so that the influence on the oscillator is small, the frequency stability is high, and the equipment is complex.

SUMMERY OF THE UTILITY MODEL

Therefore, to foretell problem, the utility model provides an automatic adjust, adjust the high, the bit error rate of accuracy is low, the novel campus security protection intercom system of the production work of being convenient for.

In order to achieve the above purpose, the utility model adopts the following technical scheme: a novel campus security intercom system comprises an interphone, wherein the interphone comprises an antenna, an RF module, a microprocessor, a key module, an A/D module, a D/A module, a loudspeaker and a microphone, the antenna is electrically connected with the microprocessor through the RF module, the key module is electrically connected with an input end of the microprocessor, an input end of the loudspeaker is electrically connected with an output end of the microprocessor through the D/A module, an output end of the microphone is electrically connected with an input end of the microprocessor through the A/D module, and the interphone further comprises an audio detection circuit and an automatic frequency modulation circuit;

The automatic frequency modulation circuit comprises a voltage-controlled oscillator, a first potentiometer, a second potentiometer, a third resistor, a fourth resistor and a crystal resonator, wherein the input end of the audio detection circuit is electrically connected with the input end of a loudspeaker, the output end of the audio detection circuit is electrically connected with the input end of the voltage-controlled oscillator, the output end of the voltage-controlled oscillator is connected with the first end of the first potentiometer, the second end of the first potentiometer is connected with the first end of the third resistor, the second end of the third resistor is grounded, the control end of the first potentiometer is connected with the first end of the fourth resistor, the control end of the second potentiometer and the crystal resonator are respectively and electrically connected with the second end of the fourth resistor, the first end of the second potentiometer is grounded, and the second end of the second potentiometer is electrically connected with a microprocessor.

Furthermore, the interphone comprises a display screen, and the display screen is electrically connected with the microprocessor.

Furthermore, the interphone further comprises a manual frequency modulation knob, and the manual frequency modulation knob is electrically connected with the microprocessor.

By adopting the technical scheme, the beneficial effects of the utility model are that: this novel campus security protection intercom system's intercom can carry out frequency control automatically, and automatic frequency modulation circuit simple structure adjusts accurate convenience through first potentiometre and second potentiometre automatic modulation, adjusts the rate of accuracy height, and the bit error rate is low, the production work of being convenient for.

Drawings

Fig. 1 is a block diagram of the overall structure of the present invention;

Fig. 2 is a circuit schematic of an automatic frequency modulation circuit.

Detailed Description

the present invention will now be further described with reference to the accompanying drawings and detailed description.

referring to fig. 1 and 2, the embodiment provides a novel campus security intercom system, which includes an intercom, the intercom includes a microprocessor 1, an RF module 2, an antenna 3, a key module 4, an a/D module 5, a D/a module 6, a microphone 7, a speaker 8, an audio detection circuit 9, an automatic frequency modulation circuit 10, a manual frequency modulation knob 11, and a display screen 12, the microprocessor 1 employs an ATM89C51 single chip microcomputer, the RF module 2, the antenna 3, the key module 4, the a/D module 5, the D/a module 6, the microphone 7, the speaker 8, the manual frequency modulation knob 11, and the display screen 12 are known circuit modules and electronic components, the audio detection circuit 9 employs an audio signal detection circuit disclosed in chinese patent publication No. CN203870972U applied on 22/05/2014, the audio signal detection circuit has an INPUT end (INPUT) and an OUTPUT end (OUTPUT), the audio signal detection circuit is used in the conventional technical means in the field. The automatic frequency modulation circuit 10 includes a voltage-controlled oscillator 101, a first potentiometer 102, a second potentiometer 103, a third resistor 104, a fourth resistor 105, and a crystal resonator 106, which are well-known electronic components in the art.

The antenna 3 is electrically connected with the microprocessor 1 through the RF module 2, the key module 4 and the manual frequency modulation knob 11 are respectively electrically connected with the input end of the microprocessor 1, the display screen 12 is electrically connected with the output end of the microprocessor 1, the input end of the loudspeaker 8 is electrically connected with the output end of the microprocessor 1 through the D/A module 6, and the output end of the microphone 7 is electrically connected with the input end of the microprocessor 1 through the A/D module 5. The input end of the audio detection circuit 9 is electrically connected with the input end of the loudspeaker 8, the audio detection circuit 9 is used for detecting the audio signal output by the microprocessor 1, and feeds back the detected audio signal to the voltage-controlled oscillator 101, the output end of the audio detection circuit 9 is electrically connected with the input end of the voltage-controlled oscillator 101, the output terminal of the voltage-controlled oscillator 101 is connected to a first terminal of a first potentiometer 102, a second terminal of the first potentiometer 102 is connected to a first terminal of a third resistor 104, a second terminal of the third resistor 104 is grounded, a control terminal of the first potentiometer 102 is connected to a first terminal of a fourth resistor 106, the control end of the second potentiometer 103 and the crystal resonator 107 are respectively electrically connected with the second end of the fourth resistor 106, a first end of the second potentiometer 103 is grounded, and a second end of the second potentiometer 103 is electrically connected with the microprocessor 1. The electrical connection mode of each circuit module and each electronic component is conventional technical means in the field. The principle of the interphone is as follows: after the quality of the audio signal is detected, the quality of the audio signal is transmitted to the automatic frequency modulation circuit 10, the automatic frequency modulation circuit 10 forms signal frequency modulation and feeds the signal frequency modulation back to the microprocessor 1, and the microprocessor 1 performs frequency modulation on the interphone until the quality of the output audio signal is optimal.

This novel campus security protection intercom system's intercom can carry out frequency control automatically, and automatic frequency modulation circuit simple structure adjusts accurate convenience through first potentiometre and second potentiometre automatic modulation, adjusts the rate of accuracy height, and the bit error rate is low, the production work of being convenient for.

While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. The utility model provides a novel campus security protection intercom system, includes the intercom, and the intercom includes antenna, RF module, microprocessor, button module, AD module, DA module, speaker, microphone, and the antenna passes through the RF module and is connected with microprocessor electricity, and button module is connected with microprocessor input electricity, and the speaker input passes through the DA module and is connected with microprocessor output electricity, and the microphone output passes through the AD module and is connected with microprocessor input electricity, its characterized in that: the interphone also comprises an audio detection circuit and an automatic frequency modulation circuit;

2. The novel campus security intercom system according to claim 1, characterized in that: the interphone comprises a display screen, and the display screen is electrically connected with the microprocessor.

3. the novel campus security intercom system according to claim 1 or 2, characterized in that: the interphone further comprises a manual frequency modulation knob, and the manual frequency modulation knob is electrically connected with the microprocessor.