阅读说明：本技术 一种兼容式车载收音机天线接口电路 (Compatible type vehicle-mounted radio antenna interface circuit ) 是由 兰伟华 汤益明 李家祥 于 2018-06-15 设计创作，主要内容包括：一种兼容式车载收音机天线接口电路,包括天线插座、收音机模块和微控制器,还包括切换模块、第一分压模块、第二分压模块和供电模块；该供电模块与第一分压模块一端和切换模块的动端相连；该天线插座与切换模块的第一静端和第二分压模块相连；该收音机模块的射频输入端连接有隔离电容,该隔离电容与天线插座相连；该微控制器设有第一AD采集口、第二AD采集口和控制口,该第一AD采集口和第二AD采集口分别与所述第一分压模块和第二分压模块相连,该控制口与切换模块控制端相连。本发明能实现有源收音机天线和无源收音机天线在多媒体设备上的兼容性使用,从而来满足客户对收音机有源天线和无源天线的个性化选择。(A compatible vehicle-mounted radio antenna interface circuit comprises an antenna socket, a radio module, a microcontroller, a switching module, a first voltage division module, a second voltage division module and a power supply module; the power supply module is connected with one end of the first voltage division module and the movable end of the switching module; the antenna socket is connected with a first static end of the switching module and the second voltage division module; the radio frequency input end of the radio module is connected with an isolation capacitor, and the isolation capacitor is connected with an antenna socket; the microcontroller is provided with a first AD acquisition port, a second AD acquisition port and a control port, wherein the first AD acquisition port and the second AD acquisition port are respectively connected with the first voltage division module and the second voltage division module, and the control port is connected with a control end of the switching module. The invention can realize the compatible use of the active radio antenna and the passive radio antenna on the multimedia equipment, thereby meeting the personalized selection of customers for the active radio antenna and the passive radio antenna.)

1. The utility model provides a compatible formula on-vehicle radio antenna interface circuit, links to each other with the radio module, includes antenna socket and microcontroller, its characterized in that: the switching module, the first voltage division module, the second voltage division module and the power supply module are further included; the power supply module is connected with one end of the first voltage division module and the movable end of the switching module; the antenna socket is connected with a first static end of the switching module and the second voltage division module; the microcontroller is provided with a first AD acquisition port, a second AD acquisition port and a control port, the first AD acquisition port and the second AD acquisition port are respectively connected with the first voltage division module and the second voltage division module to acquire voltage to calculate difference values and compare the difference values with a preset threshold value to judge the type of the antenna, and the control port is connected with a control end of the switching module to control the state of the switching module to be switched on or off according to the type of the antenna to supply power.

2. The compatible vehicle radio antenna interface circuit of claim 1, wherein: the first voltage division module comprises a first resistor and a second resistor, one end of the first resistor is connected with the power supply module, the other end of the first resistor is connected with the second resistor and the first AD acquisition port, and the other end of the second resistor is grounded.

3. The compatible vehicle radio antenna interface circuit of claim 1, wherein: the switching module is characterized by further comprising a third resistor, wherein one end of the third resistor is connected with the power supply, and the other end of the third resistor is connected with the movable end of the switching module.

4. The compatible vehicle radio antenna interface circuit of claim 1, wherein: the second voltage division module comprises a fourth resistor and a fifth resistor; one end of the fourth resistor is connected with the antenna socket, and the other end of the fourth resistor is connected with one end of the fifth resistor and the second AD acquisition port; the other end of the fifth resistor is grounded.

5. The compatible vehicle radio antenna interface circuit of claim 1, wherein: the device also comprises a sixth resistor, wherein one end of the sixth resistor is connected with the control port, and the other end of the sixth resistor is grounded.

6. The compatible vehicle radio antenna interface circuit of claim 1, wherein: and one end of the filter capacitor is connected with the second static end of the switching module, and the other end of the filter capacitor is grounded.

7. The compatible vehicle radio antenna interface circuit of claim 1, wherein: the control port is an I/0 port.

8. The compatible vehicle radio antenna interface circuit of claim 1, wherein: the radio frequency antenna further comprises an isolation capacitor, one end of the isolation capacitor is connected with the radio frequency input end of the radio module, and the other end of the isolation capacitor is connected with the antenna socket.

Technical Field

The invention relates to the field of vehicle-mounted equipment, in particular to a compatible vehicle-mounted radio antenna interface circuit.

Background

In the application of the vehicle-mounted multimedia entertainment terminal on the automobile, the vehicle-mounted multimedia entertainment terminal basically has the playing function of a radio. With the different requirements of customers on radio sets, the requirements on radio antenna configuration are different, some customers need to be provided with passive radio antennas, and some customers need to be provided with active radio antennas. However, the two antennas have different requirements and characteristics, when the active radio antenna is used, the amplifier is arranged in the active radio antenna, so that the radio antenna needs to be powered to amplify signals, and a certain amount of current, generally dozens of MA, is consumed when the antenna is powered. Whereas passive radio antennas do not require external power.

In practical applications, the two antennas are difficult to distinguish if the shape design is almost the same, or the two antennas are more difficult to identify when both antennas are installed on the roof of a vehicle and only one radio plug is left for connecting with the multimedia terminal equipment. For the aftermarket, the radio antenna is installed on the vehicle first, and then the multimedia equipment is installed later, and the problem that whether the active radio antenna or the passive radio antenna is installed on the vehicle cannot be judged is more prominent.

Therefore, in order to solve the above problems, there is a need for an interface circuit and method for a compatible car radio antenna, which automatically matches an active antenna and a passive antenna of a car radio, so that the two antennas can be compatible for use in a multimedia terminal device.

Disclosure of Invention

The invention mainly aims to provide a compatible vehicle-mounted radio antenna interface circuit which automatically matches a radio active antenna and a radio passive antenna installed on a vehicle, so that the two antennas can be used on multimedia terminal equipment.

The invention adopts the following technical scheme:

the utility model provides a compatible formula on-vehicle radio antenna interface circuit, links to each other with the radio module, includes antenna socket and microcontroller, its characterized in that: the switching module, the first voltage division module, the second voltage division module and the power supply module are further included; the power supply module is connected with one end of the first voltage division module and the movable end of the switching module; the antenna socket is connected with a first static end of the switching module and the second voltage division module; the microcontroller is provided with a first AD acquisition port, a second AD acquisition port and a control port, the first AD acquisition port and the second AD acquisition port are respectively connected with the first voltage division module and the second voltage division module to acquire voltage to calculate difference values and compare the difference values with a preset threshold value to judge the type of the antenna, and the control port is connected with a control end of the switching module to control the state of the switching module to be switched on or off according to the type of the antenna to supply power.

Preferably, the first voltage division module comprises a first resistor and a second resistor, one end of the first resistor is connected with the power supply module, the other end of the first resistor is connected with the second resistor and the first AD acquisition port, and the other end of the second resistor is grounded.

Preferably, the switching module further comprises a third resistor, one end of the third resistor is connected with the power supply, and the other end of the third resistor is connected with the movable end of the switching module.

Preferably, the second voltage division module comprises a fourth resistor and a fifth resistor; one end of the fourth resistor is connected with the antenna socket, and the other end of the fourth resistor is connected with one end of the fifth resistor and the second AD acquisition port; the other end of the fifth resistor is grounded.

Preferably, the device further comprises a sixth resistor, one end of the sixth resistor is connected with the control port, and the other end of the sixth resistor is grounded.

Preferably, the switching module further comprises a filter capacitor, one end of the filter capacitor is connected with the second static end of the switching module, and the other end of the filter capacitor is grounded.

Preferably, the control port is an I/0 port.

Preferably, the radio receiver further comprises an isolation capacitor, one end of the isolation capacitor is connected with the radio frequency input end of the radio receiver module, and the other end of the isolation capacitor is connected with the antenna socket.

As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following advantages:

1. the active and passive antenna voltage divider is provided with the first voltage dividing module, the second voltage dividing module and the like, utilizes the voltage dividing characteristic of a precision resistor, adopts a combined detection mode of double-path AD acquisition to realize the accurate judgment of the active and passive antennas, has a wider detectable voltage range, and is more suitable for active antennas of different types; and the power supply is switched on and off according to the judgment result, so that the quiescent current is greatly reduced.

2. The present invention utilizes the characteristic difference between the active antenna and the passive antenna (the active antenna consumes several tens of MA current) to convert the changed current into corresponding voltage.

3. And the input circuit matching of the active antenna and the passive antenna is realized by adopting a control mode of high and low levels of an I/O port.

4. The circuit of the invention can be applied to multimedia entertainment terminal equipment with the function of a radio, and is used for meeting the personalized selection of a client on an active antenna and a passive antenna of the radio. The antenna has the advantages of low cost, convenient application, compatibility and use of active antenna and passive antenna of the radio, accuracy and the like.

Drawings

FIG. 1 is a circuit diagram of the present invention;

FIG. 2 is a flow chart of the present invention;

wherein: u1, a microcontroller, U2, an antenna socket, U3, a radio module, K1, a switching module, S1, a control end, A1, a movable end, B1, a first static end, B2, a second static end, R1, a first resistor, R2, a second resistor, R3, a third resistor, R4, a fourth resistor, R5, a fifth resistor, R6, a sixth resistor, C1, a filter capacitor, C2, an isolation capacitor, AD0, a first AD acquisition port, AD1, a second AD acquisition port, a GPIO (general purpose input/output) and a control port.

Detailed Description

The invention is further described below by means of specific embodiments.

Referring to fig. 1, a compatible antenna interface circuit of a vehicle-mounted radio is connected to a radio module U3, and includes an antenna socket U2, a microcontroller U1, a switching module K1, a first voltage dividing module, a second voltage dividing module, a power supply module, and the like. The antenna socket U2 is used to connect an active antenna or a passive antenna, which also serves as a radio interface. The supply module is the supply voltage VCC required by the active antenna,can be selected according to requirements. At present, the power supply voltage of the vehicle-mounted active antenna is VCC, and the consumed current is I₁In practical application, the current is generally DC 12V +/-10%, and the current is dozens of milliamperes. The switching module K1 has a control terminal S1, a moving terminal a1, a first stationary terminal B1 and a second stationary terminal B2. When the control terminal S1 is at a low level, i.e. in a default state, the moving terminal a1 is connected to the first static terminal B1, the second static terminal B2 is connected to a filter capacitor C1, and the filter capacitor C1 is grounded.

The first voltage division module comprises a first resistor R1 and a second resistor R2, one end of the first resistor R1 is connected with the power supply module, the other end of the first resistor R3526 is connected with the second resistor R2, the other end of the second resistor R2 is grounded, and the connection end of the first resistor R1 and the second resistor R2 serves as a first detection point A. The invention also comprises a third resistor R3, wherein the R3 is a high-power precise small resistor, one end of the resistor is connected with the power supply module, and the other end of the resistor is connected with the movable end A1 of the switching module K1.

The second voltage division module comprises a fourth resistor R4 and a fifth resistor R5, one end of the fourth resistor R4 is connected with the antenna socket U2 and the first static end B1 of the switching module K1, the other end of the fourth resistor R4 is connected with one end of a fifth resistor R5, and the other end of the fifth resistor R5 is grounded. The connection end of the fourth resistor R4 and the fifth resistor R5 is used as a second detection point B.

The radio frequency input end of the radio module U3 is connected with an isolation capacitor C2, and the isolation capacitor C2 is connected with the antenna socket U2 to play a role in isolating direct current. Signals received by the radio antenna, namely an active antenna or a passive antenna, are input to the radio frequency input end, namely an RF _ IN pin, of the radio module U3 through the isolation capacitor C2.

This microcontroller U1 is equipped with first AD acquisition mouth AD0, second AD acquisition mouth AD1 and control mouth GPIO, and this first AD acquisition mouth AD0 and second AD acquisition mouth AD1 link to each other with the first check point A of first partial pressure module and the second check point B of second partial pressure module respectively in order to gather corresponding voltage calculation difference, and compare the difference with the predetermined threshold value and judge the antenna type, be active antenna or passive antenna promptly.

The control port GPIO is an I/O port, and is connected to the control terminal S1 of the switching module K1 to control the state of the switching module K1 according to the antenna type to turn on or off the power supply. If the antenna is an active antenna, the GPIO of the control port keeps low level, the movable end A1 is connected with the first static end B1 to connect the power supply module and the antenna socket U2, and power supply for the active antenna is realized; if the antenna is a passive antenna, the control port GPIO outputs a high level, the moving terminal a1 is operated to connect to the second static terminal B2, and the connection between the power supply module and the antenna socket U2 is cut off, i.e., the power supply is cut off.

The intelligent controller also comprises a sixth resistor R6, wherein one end of the sixth resistor R6 is connected with the control port GPIO, the other end of the sixth resistor R6 is grounded, and the sixth resistor R6 is a pull-down resistor, so that the control port GPIO is in a pull-down state at the moment when the microcontroller U1 is powered on.

The first resistor R1, the second resistor R2, the fourth resistor R4 and the fifth resistor R5 are current-limiting resistors, and R1 is equal to R4, and R2 is equal to R5 (in practical application, the sum of the resistors R4 and R5 may be about 1M ohm), so that the maximum voltage at the point a and the point B does not exceed the GPIO port voltage of the microcontroller U1, such as 3.3V, through the voltage division of R1 and R2 and the voltage division of R4 and R5.

The switching module K1 of the invention can adopt a single-pole double-throw vehicle-mounted relay, the internal resistance of which is very small and can be ignored, and other similar relays can also be adopted. Assuming that the total current passing through R3 is I, the current passing through R4 and R5 (in practice, the sum of the resistances of R4 and R5 can be about 1M ohm) is I₀This current is very small and practically negligible. For the case where the type of radio antenna is unknown, referring to fig. 2, the working principle of the present invention is as follows:

the antenna socket U2 is inserted into a radio antenna and powers on a multimedia device (a radio module U3), the voltage V1 is acquired at the point A by a first AD acquisition port AD0 of a microcontroller U1, V1 is VCC R2/(R1+ R2), the voltage V2 is acquired at the point B by a second AD acquisition port AD1 of the microcontroller U1, and V2 is VCC-R3I₀) R5/(R4+ R5, while microcontroller U1 performs internal operations, i.e., VX — V1-V2; if VX is greater than or equal to VMIN (a preset threshold value inside the microcontroller U1), indicating that an active antenna is inserted, the microcontroller U1 keeps the GPIO1 in a low level state, so that the power supply module always supplies power to the interface terminal of the radio antenna.

Inserting a radio antenna into an antenna socket U2 and powering on the multimedia device, wherein the voltage collected at the point A is V1 by a first AD collection port AD0 of a microcontroller U1, the voltage collected at the point B is V2 by a second AD collection port AD1 of the microcontroller U1, and simultaneously the microcontroller U1 carries out internal operation, namely VX is V1-V2; if VX is smaller than VMIN (the preset threshold value in the microcontroller U1), indicating that the inserted antenna is a passive antenna, the microcontroller U1 controls the GPIO1 to be in a high level state, so that the movable terminal A1 of the switching module K1 acts and is connected with the second static terminal B2, and the power supply module stops supplying power to the radio antenna.

The detection and control realize the compatible use of the active radio antenna and the passive radio antenna on the multimedia equipment, thereby meeting the personalized selection of customers for the active radio antenna and the passive radio antenna.

The above description is only an embodiment of the present invention, but the design concept of the present invention is not limited thereto, and any insubstantial modifications made by using the design concept should fall within the scope of infringing the present invention.