CN201018508Y - A pre-satellite receiving and transmitting circuit - Google Patents

Abstract

The utility model relates to the communication field, in particular to a front-end satellite receiving and transmitting circuit, which is characterized in that it includes a frequency division circuit for separating signals and power supplies, a receiving protection circuit at the transmitting end, a low-noise amplifier circuit installed at the root of the receiving antenna, and a receiving The terminal receives the protection circuit, the above circuits are connected in sequence, and the power supply voltage stabilization conversion circuit is set, and the voltage output of the frequency division circuit is provided to other circuits after the power supply voltage stabilization conversion circuit. The utility model has the performance advantages of low-noise amplification, protection, small size, etc., and is suitable for use under the conditions that the distance between satellite transceiver antennas is relatively short, the location is narrow, and the number of transmission cables is limited.

Description

A pre-satellite receiving and transmitting circuit

technical field

The utility model relates to the communication field, in particular to a front satellite receiving and transmitting circuit.

Background technique

Due to the different frequencies of satellite transmission and reception, Satcom antennas generally have two antennas for transmitting and receiving. When the distance between the transmitting and receiving antennas is relatively close, the isolation of the satellite transmitting and receiving antennas is only about ten dB or so. Therefore, when the satellite communication signal is transmitted, there will be transmission power entering the receiving antenna, and this interference signal is relatively large compared to the satellite receiving signal. At present, the duplexer, which is widely used in the field of satellite communication, needs to set up an isolation circuit to avoid signal interference between the transmitting and receiving antennas. Although it has the function of preventing large signals from entering the receiving front end, causing saturation or even burning of the received signal, it has a large space , the insertion loss is large, and the noise figure is also large, which is not convenient for use in narrow places. The prior art lacks a solution that satisfies both small space size and low-noise reception.

Utility model content

The purpose of the utility model is to design a small-volume and low-noise receiving front-end satellite receiving and transmitting circuit.

In order to achieve the purpose of the utility model, the utility model provides a front-end satellite receiving and transmitting circuit, including a frequency division circuit for separating signals and power supplies, a receiving protection circuit at the transmitting end, a low-noise amplifier circuit installed at the root of the receiving antenna, and a receiving and receiving circuit at the receiving end. The protection circuit, the above circuits are connected in sequence, and the power supply voltage stabilization conversion circuit is set, and the voltage output of the frequency division circuit is provided to other circuits after being passed through the power supply voltage stabilization conversion circuit.

Moreover, the low-noise amplifier circuit is composed of a first-stage amplifier, a filter, and a second-stage amplifier in series.

Moreover, the transmitting end receiving protection circuit is composed of a transmitting radio frequency switch and a transmitting end following protection circuit. The transmitting end following protection circuit adopts a double diode protection circuit, and the frequency division circuit selects the transmitting antenna or the transmitting end following protection through the transmitting radio frequency switch contact. circuit, the transmitting end is connected to the low noise amplifier circuit following the protection circuit.

Moreover, the receiving protection circuit at the receiving end is composed of a receiving radio frequency switch and a receiving end following protection circuit. The receiving end following protection circuit adopts a double diode protection circuit. The protection circuit is connected to the low noise amplifier circuit.

Moreover, the transmitting radio frequency switch and the receiving radio frequency switch adopt the microwave radio frequency switch 409 chip of Dowkey Company.

The front-end satellite receiving and transmitting circuit provided by the utility model is equipped with a low-noise amplifier circuit at the root of the receiving antenna, and the received signal is firstly processed and then sent to the subsequent signal processing circuit, which strengthens the quality of the received signal and improves the signal-to-noise ratio. Moreover, this processing reduces the requirement for the space distance between the two transmitting and receiving antennas, and reduces the volume of the satellite front-end equipment. The utility model is also integrated to realize the transmission and reception signal path, adopts the radio frequency switch to divide the transmission and reception process, reduces the interference of the transmission power to the reception with the simple circuit switching structure; adopts the protection circuit to prevent the damage of the amplifying device; Power supply and signal, reducing the space occupied by power supply and wiring. The invention has performance advantages such as low-noise amplification, protection and small size. Compared with the existing duplexer, the utility model is small in size and light in weight, only 1/3 to 1/4 of the size of the ordinary duplexer. Use in limited numbers.

Description of drawings

Fig. 1 is a block diagram of the utility model;

Fig. 2 is the receiving protection circuit diagram of the transmitting end of the utility model embodiment;

Fig. 3 is a frequency division circuit diagram of the embodiment of the utility model.

Detailed ways

Referring to the accompanying drawing 1 of the description, the utility model provides a pre-satellite receiving and transmitting circuit, including a frequency division circuit 1 for separating signals and power supplies, a receiving protection circuit 2 at the transmitting end, a low-noise amplifier circuit 3 installed at the root of the receiving antenna, and a receiving end receiving circuit. The protection circuit 4, the above circuits are connected in sequence, and the power supply voltage stabilization conversion circuit 5 is set, and the voltage output of the frequency division circuit 1 is provided to other circuits after the power supply voltage stabilization conversion circuit 5. The duplexer in the prior art obtains the received signal and directly transmits it to the subsequent signal processing circuit, so the signal-to-noise ratio is easily affected by the transmission frequency. The utility model sets a low-noise amplifier circuit 3 at the root of the receiving antenna, and processes the received signal first It is sent to the follow-up signal processing circuit, which enhances the quality of the received signal, improves the signal-to-noise ratio, and saves the volume of the equipment. The function of receiving protection circuit 2 at the transmitting end and receiving protection circuit 4 at the receiving end is to disconnect the receiving antenna path when the satellite is transmitting, so as to prevent large signals from entering the receiving front end, causing the receiving signal to be saturated or even burned; The signal is amplified and filtered by the low-noise amplifier circuit 3, and finally the signal is transmitted to a subsequent receiving and processing device. The satellite transmission and reception of the utility model share the signal channel, which can save volume, and the power supply and the signal of the utility model are transmitted on a coaxial cable, which further reduces the volume, and the power supply and the signal can be separated by the frequency dividing circuit 1 Respectively meet the signal transmission and power supply. Referring to FIG. 3 , the frequency division circuit 1 adopts a frequency division inductance L in specific implementation, and the frequency division inductance L can be designed as a high-frequency air-core inductance, so that the coil will not be burned when the power of the transmitting signal is coupled. After the frequency division, the voltage output of the frequency division circuit 1 is stabilized and transformed by the power supply voltage stabilization conversion circuit 5. During specific implementation, the power supply voltage stabilization conversion circuit 5 can select a voltage stabilization chip U7805 according to requirements. After frequency division, the voltage output of the frequency division circuit 1 enters through the Vin pin of the voltage regulator chip U7805, and the converted voltage is output through the Vout pin. The GND pin is connected to ground.

During specific implementation, the low-noise amplifier circuit 3 may adopt the form of a first-stage amplifier + a filter + a second-stage amplifier in series. Both stages of amplification use the HMC356LP3 chip, which has a high compression point of 1dB and can achieve the 2dB noise requirement. At the same time, the printed plate technology uses microstrip technology for low-noise matching, so that the input and output impedance of the amplifier is strictly matched to 50Ω, which not only meets the low-noise requirements, but also reduces the module size. The filter can adopt SBP347-N chip, its frequency f=327～367MHz, and the rejection ratio is 35dB.

The utility model provides a further protection circuit design scheme for implementation. Referring to FIG. 2 , the receiving protection circuit 2 at the transmitting end is composed of a transmitting radio frequency switch 21 and a following protection circuit 22 at the transmitting end. The transmitter follower protection circuit 22 adopts a double diode protection circuit, which is composed of a diode c1 with a negative pole grounded and a diode c2 with a positive pole grounded. The frequency dividing circuit 1 selects the transmitting antenna or the transmitting end follows the protection circuit 22 through the transmitting radio frequency switch contact, and the transmitting end follows the protection circuit 22 to connect to the low noise amplifier circuit 3 . The receiving end receiving protection circuit 4 is composed of a receiving radio frequency switch 41 and a receiving end following protection circuit 42. The receiving end following protection circuit 42 also adopts a double diode protection circuit, and the receiving antenna is connected to the receiving end following the protecting circuit 42 through the receiving radio frequency switch contact. , the receiving end follows the protection circuit 42 and connects to the low noise amplifier circuit 3 . The utility model adopts an idea to design the receiving protection circuit 2 at the transmitting end and the receiving protection circuit 4 at the receiving end, the difference is that the positions of the switches and the double diodes are exchanged. The radio frequency switch is used to divide the transmission and reception process, and the interference of transmission power to reception is reduced with a simple circuit switching structure.

The transmitting radio frequency switch and the receiving radio frequency switch can use the microwave radio frequency switch 409 chip of dowkey company. Just control the power on and off, and the 409 chip can quickly respond to change channels.

When Satcom is receiving, the receiving radio frequency switch 41 is turned on and is in the receiving position. The signal received by the satellite antenna first passes through the receiving end to follow the protection circuit 42, the purpose is to prevent damage to the amplifier by an unexpected large current, and then passes through the primary amplification 33, filter 32, and secondary amplification 31 of the low-noise amplifier circuit 3, and finally The signal is transmitted to a subsequent signal processing device through the frequency division circuit 1 for receiving processing. At this time, the DC power supply and the received signal are bidirectionally transmitted on a cable, and the DC power supply passes through the frequency division circuit 1 as a power supply.

During satellite transmission, the frequency division circuit 1 separates the power supply from the transmission signal, the transmission signal selects the transmission position through the transmission radio frequency switch 21, and transmits the transmission signal through the transmission antenna. At this time, the receiving radio frequency switch 41 is turned off, that is, the transmitting signal coupled by the receiving antenna is disconnected from the receiving part of the circuit, and connected to the low noise amplifier circuit 3 for protection.

Claims (6)

1. a preposition satellite receives radiating circuit; it is characterized in that: the frequency dividing circuit, the transmitting terminal that comprise separation signal and power supply receive protective circuit, the low noise amplifier circuit that is installed in the reception antenna root and receiving terminal reception protective circuit; above circuit connects in turn; power supply voltage stabilizing translation circuit is set, and the voltage output of frequency dividing circuit provides to other circuit behind power supply voltage stabilizing translation circuit.

2. preposition satellite according to claim 1 receives radiating circuit, it is characterized in that: low noise amplifier circuit is made of one-level amplifier, filter, two-stage amplifier series connection.

3. preposition satellite according to claim 1 and 2 receives radiating circuit; it is characterized in that: transmitting terminal reception protective circuit is followed protective circuit by emission radio-frequency (RF) switch and transmitting terminal and is constituted; described transmitting terminal is followed protective circuit and is adopted the double diode protective circuit; the signal output part of frequency dividing circuit is followed protective circuit through emission radio-frequency (RF) switch contact gating transmitting antenna or transmitting terminal, and the output of low noise amplifier circuit inserts transmitting terminal and follows protective circuit.

4. preposition satellite according to claim 1 and 2 receives radiating circuit; it is characterized in that: receiving terminal reception protective circuit is followed protective circuit by received RF switch and receiving terminal and is constituted; described receiving terminal is followed protective circuit and is adopted the double diode protective circuit; reception antenna connects receiving terminal through the received RF switch contact and follows protective circuit, and receiving terminal is followed protective circuit and inserted low noise amplifier circuit.

5. preposition satellite according to claim 3 receives radiating circuit, it is characterized in that: described emission radio-frequency (RF) switch adopts microwave radio switch 409 chips of dowkey company.

6. preposition satellite according to claim 4 receives radiating circuit, it is characterized in that: described received RF switch adopts microwave radio switch 409 chips of dowkey company.

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