Terrestrial digital television system active receiving antenna with gain adjusting function

Abstract

The utility model discloses a terrestrial digital television system active receiving antenna with a gain adjusting function, comprising an antenna circuit, the antenna circuit comprises a passive antenna, a low noise amplifier, a numerical control attenuator, an MCU microprocessor and a power divider which are electrically connected in sequence and can receive UHF frequency band signals, the passive antenna receives space digital television signals, and the power divider receives the space digital television signals. The low noise amplifier is used for amplifying signals, a processing program for changing the level of the numerical control attenuator is arranged in the MCU microprocessor, the numerical control attenuator is used for controlling the attenuation amount of space digital television signals, and the MCU microprocessor calls the corresponding processing program to change the level of the numerical control attenuator so as to control the attenuation amount of the space digital television signals. According to the technical scheme of the utility model, gain adjustment of the active antenna of the digital television can be realized, power distribution or combination of digital television signals can be realized, a multi-stage cascade combination function of the antenna can be realized, and the power divider can be flexibly used for circuit optimization.

Description

Technical Field

[0001] The utility model relates to the technical field of active receiving antennas, in particular to an active receiving antenna of a terrestrial digital television system with a gain adjustment function. Background Art

[0002] In the cable TV system, the task of the antenna is to receive the open-circuit TV signal or satellite TV signal in the air and send it to the system for processing, transmission and distribution. The antenna that receives the open-circuit TV signal in the VHF and UHF frequency bands is called a TV receiving antenna. The TV receiving antenna is an important part of wireless TV signal reception and is the gateway for radio waves to enter the cable TV system. There are two types of antennas: passive antennas and active antennas. Active antennas can enable the antenna system to achieve high gain and high signal-to-noise ratio reception.

[0003] The signal-to-noise ratio (SNR) refers to the ratio of the signal to the noise in an electronic device or electronic system. The signal-to-noise ratio is an important indicator for measuring the performance of a communication system or electronic device. It indicates the ratio of the strength of the useful signal received by the device to the strength of the interference signal (including noise and interference) received. In an audio amplifier, the larger the signal-to-noise ratio, the smaller the noise mixed in the signal, and the higher the sound quality of the sound playback; conversely, the lower the sound quality. Low-noise amplifiers (LNAs), amplifiers with very low noise figures, are generally used as high-frequency or intermediate-frequency preamplifiers for various types of radio receivers, as well as amplifier circuits for highly sensitive electronic detection equipment. When amplifying weak signals, the noise of the amplifier itself may seriously interfere with the signal, so it is hoped to reduce this noise to improve the output signal-to-noise ratio.

[0004] However, the active gain of the low-noise amplifier of the active receiving antenna of the existing terrestrial digital television system on the market is generally not adjustable. When the receiving position of the antenna is close to the transmitter, the gain of the low-noise amplifier is high, which will cause gain compression in the back-end link and lead to deterioration of the system signal-to-noise ratio; when the receiving position of the antenna is far from the transmitter, the gain of the low-noise amplifier is low and cannot effectively compensate for the cable transmission loss, which will also lead to deterioration of the system signal-to-noise ratio. Utility Model Content

[0005] The main purpose of the utility model is to provide an active receiving antenna for a terrestrial digital television system with a gain adjustment function, aiming to solve the technical problem that when the distance between the existing antenna receiving position and the transmitting station position changes, the active gain of the low-noise amplifier cannot be adjusted, resulting in the inability to stabilize the system signal-to-noise ratio.

[0006] To achieve the above-mentioned purpose, the utility model proposes an active receiving antenna for a terrestrial digital television system with a gain adjustment function, comprising an antenna circuit and a button, wherein the button controls the level inside the antenna circuit by the number of external pressings, and the antenna circuit comprises a passive antenna, a low-noise amplifier, a digitally controlled attenuator, an MCU microprocessor and a power divider which are electrically connected in sequence, wherein the passive antenna receives a spatial digital television signal in the UHF frequency band, the low-noise amplifier is used to amplify the spatial digital television signal, the MCU microprocessor writes a pre-programmed processing program, and the MCU microprocessor calls out the corresponding processing program according to the number of pressings of the button to change the level of the digitally controlled attenuator, the digitally controlled attenuator controls the attenuation of the spatial digital television signal, and the power divider is used to divide the spatial digital television signal into two signals and output them to the rear end circuit of the antenna circuit.

[0007] Optionally, the antenna circuit further includes a first patch capacitor and resistor, which are electrically connected to the antenna circuit. The first patch capacitor and resistor can use the power divider as a combiner by changing a patch position.

[0008] Optionally, the antenna circuit is further provided with a power adapter, the power adapter is electrically connected to the antenna circuit, and the power adapter is used to provide a direct current power supply to the antenna circuit.

[0009] Optionally, the antenna circuit is provided with an output port 1 and an output port 2, and the output port 1 and the output port 2 are electrically connected in parallel to the rear end circuit of the antenna circuit.

[0010] Optionally, the power divider is a bisection power divider.

[0011] The technical solution of the utility model has the following beneficial effects: in the technical solution of the utility model, a digital television (UHF band) passive antenna is set to receive a spatial signal, which is transmitted to an LNA (low noise amplifier) ​​for amplification. The amplified signal passes through a digitally controlled attenuator, and the digitally controlled attenuator is controlled by an MCU, so that the gain of the digital television active antenna can be adjusted. The power distribution or combining of the digital television signal can be achieved through the adjustment scheme of the two-way power divider and the first chip capacitor resistor. By using a coaxial cable and a power adapter, coaxial power supply or separate power supply can be used, which enriches the use functions and scenarios. The two-way power divider can be By modifying the positions of the two jumpers (or the first chip capacitor and resistor) in the antenna circuit, another function of the antenna - the multi-stage cascade circuit function - can be realized, and the power divider can be flexibly used to optimize the circuit to meet the needs in different situations. Furthermore, the antenna circuit also has an LNA integrated bypass function (Bypass). A switch K is provided in the antenna circuit. Considering that when the received signal is too strong, the LNA circuit power will be overloaded, resulting in a deterioration of the signal-to-noise ratio, the manual switch K can be used to disconnect the LNA amplification circuit, so that the signal received by the passive antenna is bypassed without amplification and directly transmitted to the output port, thereby optimizing the use function of the antenna circuit to adapt to more complex situations. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0013] Figure 1 This is a principle circuit diagram of an active receiving antenna of a terrestrial digital television system with a gain adjustment function according to an embodiment of the utility model;

[0014] Figure 2 for Figure 1 Simplified schematic circuit diagram of

[0015] Figure 3 A circuit diagram of a two-equal power distributor of an active receiving antenna of a terrestrial digital television system with a gain adjustment function according to an embodiment of the utility model;

[0016] Figure 4 A circuit diagram of a two-way power divider as a combiner of an active receiving antenna of a terrestrial digital television system with a gain adjustment function according to an embodiment of the utility model;

[0017] Figure 5 for Figure 4Antenna multi-stage cascade circuit diagram;

[0018] Figure 6 The present invention is a circuit diagram of an amplifier bypass of an active receiving antenna of a terrestrial digital television system with a gain adjustment function according to an embodiment of the present invention.

[0019] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0021] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back...) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0022] In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0023] The utility model provides an active receiving antenna for a terrestrial digital television system with a gain adjustment function.

[0024] like Figures 1 to 3As shown, in one embodiment of the utility model, the terrestrial digital television system active receiving antenna with gain adjustment function includes an antenna circuit, wherein the antenna circuit includes a passive antenna 100, a low noise amplifier 200, a digitally controlled attenuator 300, an MCU microprocessor 400 and a power divider 500 electrically connected in sequence, wherein the passive antenna 100 is used to receive a spatial digital television signal in the UHF frequency band, the low noise amplifier 200 is used to amplify the spatial digital television signal, the MCU microprocessor 400 is built with a processing program for changing the level of the digitally controlled attenuator 300, the digitally controlled attenuator 300 is used to control the attenuation of the spatial digital television signal, and the digitally controlled attenuator 300 is controlled by calling the processing program built in the MCU microprocessor 400 to control the attenuation of the spatial digital television signal, thereby realizing the adjustable gain of the digital television active antenna, and the power divider 500 is used to divide the spatial digital television signal into two signals and output them to the rear end circuit of the antenna circuit, The antenna circuit is provided with an output port 1 (PORT1) and an output port 2 (PORT2), and the output port 1 (PORT1) and the output port 2 (PORT2) are connected in parallel to the antenna circuit. The passive antenna 100 receives the spatial digital television signal and transmits it to the low noise amplifier (LNA) 200 for amplification to compensate for the loss of the back-end power distribution and the cable and improve the system signal-to-noise ratio. The amplified signal passes through a two-equal power divider 500, and the signal is divided into two paths and output from the output port 1 (PORT1) and the output port 2 (PORT2) to form a radio frequency loop. The antenna circuit is also provided with a power adapter 600, and the power adapter is electrically connected to the antenna circuit. The power adapter is used to provide a direct current power supply for the antenna circuit. The power adapter is a direct current DC12V power supply terminal to supply power to the antenna circuit. Due to the characteristics of inductance passing direct current and isolating alternating current and capacitor passing alternating current and isolating direct current, the antenna circuit uses inductance and capacitor to separate the radio frequency signal and the direct current power supply.

[0025] like Figures 4 to 6As shown, in another embodiment of the utility model, the conductor between the output port 1 (PORT1) and / or the output port 2 (PORT2) adopts a coaxial cable, and the coaxial cable includes a central conductor, an outer conductor and a shell arranged in sequence from the inside to the outside, an insulating medium is provided between the central conductor and the outer conductor, and the shell embeds the central conductor, the insulating medium and the outer conductor, and an electromagnetic field is formed between the central conductor and the outer conductor, which can generate an electromagnetic wave effect to realize coaxial power supply. The power supply (DC5-16V) required for the operation of the low noise amplifier 200 circuit is provided by the output port 1 (PORT1) or the output port 2 (PORT2) through the radio frequency coaxial cable. The two power supply modes can enrich the use scenarios and further expand the use functions. The antenna circuit also includes a first patch capacitor resistor. The first patch capacitor resistor can use the power divider as a combiner by changing the patch position. By changing the position of the two jumpers (or the first patch capacitor resistor) in the circuit, another function of the antenna—multi-stage cascade combining function—can be realized, and the power divider can be flexibly used for circuit optimization. In order to meet the needs in different situations, the UHF band passive antenna receives the spatial signal and transmits it to the LNA (low noise amplifier) ​​for amplification to compensate for the back-end power distribution and cable loss and improve the system signal-to-noise ratio. When the antenna cascade is used, the signal of the other antenna of the cascade is input from the output port 2 (PORT2), and the two signals are combined into one signal through the power divider and output to the output port 1 (PORT1). The power supply (DC5-16V) required for the operation of the low noise amplifier circuit is provided by the output port 1 (PORT1) through the RF coaxial cable. The LNA power supply can also be provided by the DC12V power supply terminal. When the output port 2 (PORT2) is connected to the cascade antenna, the DC12V power supply can also power the cascade antenna; the antenna circuit also has an LNA integrated bypass function (Bypass). Considering that when the received signal is too strong, the LNA circuit power will be overloaded, resulting in a deterioration of the signal-to-noise ratio, the antenna circuit is provided with a switch K. The manual switch K can be used to disconnect the LNA amplification circuit, so that the signal received by the passive antenna is bypassed without amplification and directly transmitted to the output port.

[0026] Specifically, the working principle and process of the utility model are as follows: a passive antenna receives a spatial digital television signal, which reaches a low-noise amplifier through a matching circuit, enters a digitally controlled attenuator after amplification, and a processing program built into an MCU for controlling the level of the digitally controlled attenuator controls the digitally controlled attenuator, and the digitally controlled attenuator performs corresponding attenuation on the signal. Finally, the signal passes through a power divider and is divided into two paths and output to a back-end circuit of a digital television system. The level of the digitally controlled attenuator pin is changed through a processing program built into the MCU microprocessor for controlling the level of the digitally controlled attenuator to control the attenuation of the signal, thereby adjusting the size of the active gain of the low-noise amplifier (LNA).

[0027] The utility model has the following advantages:

[0028] 1. Receive the spatial signal of UHF band through the passive antenna, transmit the spatial signal to LNA (low noise amplifier) ​​for amplification, and the amplified signal passes through the digital controlled attenuator, which is controlled by MCU, so that the gain of digital TV active antenna can be adjusted;

[0029] 2. Through the adjustment scheme of the bisection power divider and the first chip capacitor resistor, the power distribution or combining of the digital TV signal can be realized;

[0030] 3. Using coaxial cable and power adapter, you can use coaxial power supply or separate power supply, which enriches the use functions and scenarios;

[0031] 4. The two-way power divider can realize another function of the antenna - multi-stage cascade circuit function by modifying the positions of the two jumpers (or the first chip capacitor resistor) in the antenna circuit. The power divider can be flexibly used to optimize the circuit to meet the needs of different situations.

[0032] 5. Furthermore, the antenna circuit also has an LNA integrated bypass function (Bypass). Considering that when the received signal is too strong, the LNA circuit power will be overloaded, resulting in a deterioration of the signal-to-noise ratio, the manual switch K can be used to disconnect the LNA amplifier circuit, so that the signal received by the passive antenna is bypassed without amplification and directly transmitted to the output port, thereby optimizing the use function of the antenna circuit to adapt to more complex situations.

[0033] The above description is only a preferred embodiment of the utility model, and does not limit the patent scope of the utility model. All equivalent structural changes made by using the contents of the utility model specification and drawings under the utility model concept, or directly / indirectly used in other related technical fields are included in the patent protection scope of the utility model.

Claims

1. An active receiving antenna for a terrestrial digital television system with a gain adjustment function, characterized in that: The invention comprises an antenna circuit, wherein the antenna circuit comprises a passive antenna, a low noise amplifier, a digitally controlled attenuator, an MCU microprocessor and a power divider which are electrically connected in sequence, wherein the passive antenna is used to receive a spatial digital television signal in the UHF frequency band, the low noise amplifier is used to amplify the spatial digital television signal, the MCU microprocessor is provided with a built-in processing program for changing the level of the digitally controlled attenuator, the digitally controlled attenuator is used to control the attenuation of the spatial digital television signal, and the power divider is used to divide the spatial digital television signal into two signals and output them to the rear end circuit of the antenna circuit.

2. The active receiving antenna for a terrestrial digital television system with a gain adjustment function according to claim 1, characterized in that: The antenna circuit also includes a first patch capacitor and resistor, which are electrically connected to the antenna circuit. The first patch capacitor and resistor can use the power divider as a combiner by changing the patch position.

3. The active receiving antenna for a terrestrial digital television system with a gain adjustment function according to claim 1, characterized in that: The antenna circuit is also provided with a power adapter, which is electrically connected to the antenna circuit and is used to provide a direct current power supply to the antenna circuit.

4. The active receiving antenna for a terrestrial digital television system with a gain adjustment function according to claim 1, characterized in that: The antenna circuit is provided with an output port 1 and an output port 2, and the output port 1 and the output port 2 are electrically connected in parallel to a rear end circuit of the antenna circuit.

5. The active receiving antenna for a terrestrial digital television system with a gain adjustment function according to claim 1, characterized in that: The power divider is a two-equal power divider.

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