CN202679354U - Frequency selector for frequency modulation interphone - Google Patents
Frequency selector for frequency modulation interphone Download PDFInfo
- Publication number
- CN202679354U CN202679354U CN2012203163632U CN201220316363U CN202679354U CN 202679354 U CN202679354 U CN 202679354U CN 2012203163632 U CN2012203163632 U CN 2012203163632U CN 201220316363 U CN201220316363 U CN 201220316363U CN 202679354 U CN202679354 U CN 202679354U
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Abstract
The utility model discloses a frequency selector for a frequency modulation interphone, comprising a filtering circuit and a frequency selection circuit which is connected with the filtering circuit, wherein the filtering circuit is connected with a signal input end; the frequency selection circuit is connected with a signal output end; a voltage amplitude limit circuit is connected with the circuit between the filtering circuit and the frequency selection circuit; the voltage amplitude limit circuit comprises a first diode and a second diode; both the negative electrode of the first diode and the positive electrode of the second diode are connected with the circuit between the filtering circuit and the frequency selection circuit; and both the positive electrode of the first diode and the negative electrode of the diode are grounded. The frequency selector for a frequency modulation interphone uses the above structure, and is simple in the whole structure and convenient to realize. Besides, the frequency selector for a frequency modulation interphone can avoid inputting excessive voltage to the inner circuit in the interphone so as to prevent the a field effect transistor in the interphone from being damaged because of excessive voltage, by means of the amplitude limit effect of the voltage amplitude limit circuit during the work process of the frequency selector for a frequency modulation interphone.
Description
Technical field
The utility model relates to communication equipment field, specifically the frequency-selector of frequency-modulation intercom for use.
Background technology
In modern communications, intercom be a kind of closely, simple wireless transmission means of communication because it does not need terminal and switch station, ground to support just can carry out effective mobile communication, so be loved by the people.Intercom can be divided into amplitude modulation and frequency modulation type on modulation system, wherein, frequency-modulation intercom for use is to make the receive frequency of one group of intercom identical with the tranmitting frequency of another group intercom with tranmitting frequency by regulating frequency and receive frequency, thereby realizes the wireless communication facility of intercommunication function.Frequency-modulation intercom for use is widely used in the industries such as public security, civil aviaton, transportation, water conservancy, railway, manufacturing, building, service, and especially in the place that network can't cover, frequency-modulation intercom for use becomes the means of communication that people like.Yet during existing frequency-modulation intercom for use work, if the overtension that produces on its antenna, the grid of field effect transistor is easily breakdown and damage in the intercom, and process is loaded down with trivial details when the element in the intercom changed, and this has just affected applying of intercom.
The utility model content
The purpose of this utility model is to overcome the deficiencies in the prior art, provide a kind of simple in structure, be convenient to realize, and can with the antenna reception of intercom to voltage carry out amplitude limit, thereby can avoid the frequency-selector of the frequency-modulation intercom for use that field effect transistor in the intercom damages because of overtension.
The purpose of this utility model is achieved through the following technical solutions: the frequency-selector of frequency-modulation intercom for use, comprise filter circuit and the frequency selection circuit that is connected with filter circuit, described filter circuit is connected with signal input part, frequency selection circuit is connected with signal output part, be connected with voltage limiter circuit on the circuit between filter circuit and the frequency selection circuit, described voltage limiter circuit comprises the first diode and the second diode, described the first diode cathode and the second diode cathode all are connected on the circuit between filter circuit and the frequency selection circuit, the first diode cathode and the equal ground connection of the second diode cathode.
Described filter circuit comprises the first electric capacity, the second electric capacity and the first inductance, described the first inductance two ends respectively with the first electric capacity be connected electric capacity and be connected, the first electric capacity be connected electric capacity and relatively connect the other end ground connection of the first inductance end, described signal input part is connected on the circuit between the first electric capacity and the first inductance, and the link of described frequency selection circuit and filter circuit is connected on the circuit between the first inductance and the second electric capacity.
Described frequency selection circuit comprises the first resistance, the second resistance and the 3rd electric capacity, described the second resistance two ends are connected with the 3rd electric capacity with the first resistance respectively, the the first resistance other end equal ground connection of connecting second resistance terminal relative to the 3rd electric capacity, the link of described filter circuit and frequency selection circuit is connected on the circuit between the first resistance and the second resistance, and described signal output part is connected on the circuit between the second resistance and the second electric capacity.
Compared with prior art, the utlity model has following beneficial effect: the utility model comprises filter circuit, frequency selection circuit and voltage limiter circuit, wherein, voltage limiter circuit comprises the first diode and the second diode, the utility model realizes that the components and parts of voltage limiter circuit are few, simple in structure, be convenient to realize, cost is low, utilize the lower characteristic of diode forward pressure drop during the utility model work, can be with voltage amplitude limit in the input intercom below 0.7V, thus can avoid in the intercom field effect transistor to damage because of high pressure, and this just more is conducive to applying of intercom.
Description of drawings
Fig. 1 is the structural representation of the utility model embodiment.
The corresponding name of Reference numeral is called in the accompanying drawing: C1-first electric capacity, C2-second electric capacity, C3-the 3rd electric capacity, R1-first resistance, R2-second resistance, L1-first inductance, D1-first diode, D2-second diode, 1-signal input part, 2-signal output part.
Embodiment
The utility model is described in further detail below in conjunction with embodiment and accompanying drawing, but execution mode of the present utility model is not limited to this.
Embodiment:
As shown in Figure 1, the frequency-selector of frequency-modulation intercom for use, comprise filter circuit and the frequency selection circuit that is connected with filter circuit, wherein, filter circuit comprises the first capacitor C 1, the second capacitor C 2 and the first inductance L 1, the first inductance L 1 two ends respectively with the first capacitor C 1 be connected capacitor C 2 and be connected, the first capacitor C 1 be connected capacitor C 2 both relatively connect other end ground connection of the first inductance L 1 ends, be connected with signal input part 1 on the circuit between the first capacitor C 1 and the first inductance L 1, the link of frequency selection circuit and filter circuit is connected on the circuit between the first inductance L 1 and the second capacitor C 2.Be connected with voltage limiter circuit on the circuit between filter circuit and the frequency selection circuit, voltage limiter circuit comprises the first diode D1 and the second diode D2, the first diode D1 negative pole and the second diode D2 positive pole all are connected on the circuit between filter circuit and the frequency selection circuit, the anodal and equal ground connection of the second diode D2 negative pole of the first diode D1.
Frequency selection circuit comprises the first resistance R 1, the second resistance R 2 and the 3rd capacitor C 3, the second resistance R 2 two ends are connected with the 3rd capacitor C 3 with the first resistance R 1 respectively, the first resistance R 1 and the 3rd capacitor C 3 both relative equal ground connection of the other end that connect the second resistance R 2 ends, the link of filter circuit and frequency selection circuit is connected on the circuit between the first resistance R 1 and the second resistance R 2, is connected with signal output part 2 on the circuit between the second resistance R 2 and the second capacitor C 2.
When the frequency-selector of frequency-modulation intercom for use is worked, the voltage that interphone antenna receives is inputted frequency selection circuit after the wave circuit filtering after filtration, if the overtension of filter circuit output, the first diode D1 and the second diode D2 of voltage limiter circuit carry out amplitude limit to voltage, carry out frequency-selecting in the input frequency selection circuit after voltage is processed through voltage limiter circuit and process.
As mentioned above, then can well realize the utility model.
Claims (3)
1. the frequency-selector of frequency-modulation intercom for use, it is characterized in that: comprise filter circuit and the frequency selection circuit that is connected with filter circuit, described filter circuit is connected with signal input part (1), frequency selection circuit is connected with signal output part (2), be connected with voltage limiter circuit on the circuit between filter circuit and the frequency selection circuit, described voltage limiter circuit comprises the first diode (D1) and the second diode (D2), on the anodal circuit that all is connected between filter circuit and the frequency selection circuit of described the first diode (D1) negative pole and the second diode (D2), the first diode (D1) positive pole and the equal ground connection of the second diode (D2) negative pole.
2. the frequency-selector of frequency-modulation intercom for use according to claim 1, it is characterized in that: described filter circuit comprises the first electric capacity (C1), the second electric capacity (C2) and the first inductance (L1), described the first inductance (L1) two ends respectively with the first electric capacity (C1) be connected electric capacity (C2) and be connected, the first electric capacity (C1) be connected electric capacity (C2) both relatively connect the other end ground connection of the first inductance (L1) end, described signal input part (1) is connected on the circuit between the first electric capacity (C1) and the first inductance (L1), and the link of described frequency selection circuit and filter circuit is connected on the circuit between the first inductance (L1) and the second electric capacity (C2).
3. the frequency-selector of frequency-modulation intercom for use according to claim 1 and 2, it is characterized in that: described frequency selection circuit comprises the first resistance (R1), the second resistance (R2) and the 3rd electric capacity (C3), described the second resistance (R2) two ends are connected with the 3rd electric capacity (C3) with the first resistance (R1) respectively, both connect the equal ground connection of the other end of the second resistance (R2) end relatively the first resistance (R1) and the 3rd electric capacity (C3), the link of described filter circuit and frequency selection circuit is connected on the circuit between the first resistance (R1) and the second resistance (R2), and described signal output part (2) is connected on the circuit between the second resistance (R2) and the second electric capacity (C2).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012203163632U CN202679354U (en) | 2012-07-03 | 2012-07-03 | Frequency selector for frequency modulation interphone |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012203163632U CN202679354U (en) | 2012-07-03 | 2012-07-03 | Frequency selector for frequency modulation interphone |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202679354U true CN202679354U (en) | 2013-01-16 |
Family
ID=47500226
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2012203163632U Expired - Fee Related CN202679354U (en) | 2012-07-03 | 2012-07-03 | Frequency selector for frequency modulation interphone |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202679354U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103532580A (en) * | 2012-07-03 | 2014-01-22 | 成都市宏山科技有限公司 | Frequency selector of frequency modulation interphone |
-
2012
- 2012-07-03 CN CN2012203163632U patent/CN202679354U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103532580A (en) * | 2012-07-03 | 2014-01-22 | 成都市宏山科技有限公司 | Frequency selector of frequency modulation interphone |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20130116 Termination date: 20130703 |