S-band frequency converter for Tiantong satellite communication system detection equipment

Abstract

The utility model discloses an S-band frequency converter for Tiantong satellite communication system detection equipment, and belongs to the technical field of satellite communication systems. Comprising a first mixer; the output ends of the first band-pass filter and the first local oscillator signal circuit are connected to the input end of the first mixer; the input end of the first frequency conversion filter circuit is connected to the output end of the first frequency mixer; the input end of the second frequency mixer is connected to the output end of the first frequency conversion filter circuit; the output end of the second local oscillator signal circuit is connected to the input end of the second mixer; and the input end of the second frequency conversion filter circuit is connected with the output end of the second mixer. The S-band frequency converter disclosed by the utility model solves the problem of converting a Tiantong 2185MHz receiving signal into a 1995MHz transmitting signal, adopts a secondary frequency conversion framework, reduces intermodulation and harmonic waves generated in a frequency conversion process, improves system linearity, and can be applied to detection equipment of a Tiantong satellite system.

Description

Technical Field

[0001] This utility model belongs to the technical field of satellite communication systems, specifically, it relates to an S-band frequency converter for testing equipment of the Tiantong satellite communication system. Background Technology

[0002] With the continuous development of the Tiantong satellite communication system, it is widely used in various fields such as marine fisheries, emergency rescue, the Internet of Things, and the military. Therefore, as a component of the Tiantong system, the performance of testing equipment has a significant impact on its operation. Consequently, there is an urgent need to convert the 2185MHz received signal to a 1995MHz transmitted signal for use in the testing of Tiantong equipment. Utility Model Content

[0003] In response to the problems in related technologies, this utility model proposes an S-band frequency converter for testing equipment of the Tiantong satellite communication system, so as to overcome the above-mentioned technical problems existing in the existing related technologies.

[0004] Therefore, the specific technical solution adopted by this utility model is as follows: An S-band frequency converter for a Tiantong satellite communication system testing device, comprising:

[0005] First mixer;

[0006] The output terminals of the first bandpass filter and the first local oscillator signal circuit are both connected to the input terminal of the first mixer;

[0007] The first frequency conversion filter circuit has its input terminal connected to the output terminal of the first mixer;

[0008] The input terminal of the second mixer is connected to the output terminal of the first frequency conversion filter circuit;

[0009] The output terminals of the second local oscillator signal circuit are all connected to the input terminals of the second mixer;

[0010] The input terminal of the second frequency conversion filter circuit is connected to the output terminal of the second mixer.

[0011] In a further embodiment, the first frequency conversion filter circuit includes:

[0012] The first π-type attenuator is connected to the output terminal of the first mixer;

[0013] The second bandpass filter is connected to the output of the first π-type attenuator;

[0014] The first amplifier is connected to the output of the second bandpass filter;

[0015] A third bandpass filter is connected to the output of the first amplifier.

[0016] In a further embodiment, the first local oscillator signal circuit includes:

[0017] The first phase-locked loop is configured to generate the first local oscillator signal;

[0018] The fifth bandpass filter has its input terminal connected to the output terminal of the first phase-locked loop;

[0019] The second amplifier is connected to the output of the fifth bandpass filter;

[0020] The fourth π-type attenuator has its input connected to the output of the second amplifier; the output of the fourth π-type attenuator is connected to the first mixer.

[0021] In a further embodiment, the second frequency conversion filter circuit includes:

[0022] The second π-type attenuator is connected to the output terminal of the second mixer;

[0023] The fourth bandpass filter is connected to the output of the second π-type attenuator;

[0024] The third π-type attenuator is connected to the output of the fourth bandpass filter;

[0025] The first low-pass filter is connected to the output of the third π-type attenuator.

[0026] In a further embodiment, the second local oscillator signal circuit includes:

[0027] The second phase-locked loop is configured to generate the second local oscillator signal;

[0028] The sixth bandpass filter has its input terminal connected to the output terminal of the second phase-locked loop;

[0029] The third amplifier is connected to the output of the sixth bandpass filter;

[0030] The fifth π-type attenuator has its input connected to the output of the third amplifier; the output of the fifth π-type attenuator is connected to the second mixer.

[0031] In a further embodiment, it further includes: a reference frequency source module; the reference frequency source module includes:

[0032] Thermostatic crystal oscillator;

[0033] The fourth amplifier has its input terminal connected to the output terminal of the thermostatic crystal oscillator;

[0034] The sixth π-type attenuator is connected to the output of the fourth amplifier;

[0035] The power divider has its input terminal connected to the output terminal of the sixth π-type attenuator;

[0036] The seventh π-type attenuator and the eighth π-type attenuator are connected in parallel to the output terminal of the power divider; the output terminals of the seventh π-type attenuator and the eighth π-type attenuator are respectively connected to the first local oscillator signal circuit and the second local oscillator signal circuit.

[0037] In a further embodiment, it also includes an external control program interface to complete the output control of the local oscillator signal. The beneficial effects of this invention are: the S-band frequency converter disclosed in this invention solves the problem of converting the 2185MHz received signal of the Tiantong satellite system to a 1995MHz transmitted signal. The frequency converter adopts a two-stage frequency conversion architecture, reducing intermodulation and harmonics generated during frequency conversion and improving system linearity. It can be applied to the testing equipment of the Tiantong satellite system.

[0038] The device has an external control program interface. Under the joint control of the external control program and the microcontroller, through secondary frequency conversion and in conjunction with amplification and filtering circuits, it can convert a 2185MHz received signal into a 1995MHz transmitted signal. This invention is particularly suitable for testing equipment requiring a Tiantong satellite communication system. Attached Figure Description

[0039] Figure 1 This is a topology diagram of an S-band frequency converter used in the testing equipment for the Tiantong satellite communication system.

[0040] Figure 2 This is a connection diagram for the reference frequency source module. Detailed Implementation

[0041] To further illustrate the various embodiments, the present invention provides accompanying drawings, which are part of the disclosure of the present invention. These drawings are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these drawings, those skilled in the art should be able to understand other possible implementation methods and the advantages of the present invention.

[0042] Example 1

[0043] This embodiment discloses an S-band frequency converter for a testing device of the Tiantong satellite communication system, including: a first mixer;

[0044] The output terminals of the first bandpass filter and the first local oscillator signal circuit are both connected to the input terminal of the first mixer;

[0045] The first frequency conversion filter circuit has its input terminal connected to the output terminal of the first mixer;

[0046] The input terminal of the second mixer is connected to the output terminal of the first frequency conversion filter circuit;

[0047] The output terminals of the second local oscillator signal circuit are all connected to the input terminals of the second mixer;

[0048] The input terminal of the second frequency conversion filter circuit is connected to the output terminal of the second mixer.

[0049] like Figure 1 As shown, the first frequency conversion filter circuit includes: a first π-type attenuator connected to the output terminal of the first mixer, a second bandpass filter connected to the output terminal of the first π-type attenuator, a first amplifier connected to the output terminal of the second bandpass filter, and a third bandpass filter connected to the output terminal of the first amplifier.

[0050] The first amplifier is connected to the output of the second bandpass filter to amplify the signal. The first amplifier is selected as a high-gain, high-third-order, high-output P-1dB amplifier, and has good gain flatness characteristics in this application frequency band. The third bandpass filter is connected to the output of the first amplifier to perform bandpass filtering on the amplified signal again. The second and third bandpass filters can filter out RF leakage, local oscillator leakage and spurious signals of each order combination. The out-of-band rejection ratio is above 50dBc, which can meet the performance requirements.

[0051] The first local oscillator signal circuit includes:

[0052] The first phase-locked loop is configured to generate the first local oscillator signal;

[0053] The fifth bandpass filter has its input terminal connected to the output terminal of the first phase-locked loop;

[0054] The second amplifier is connected to the output of the fifth bandpass filter;

[0055] The fourth π-type attenuator has its input connected to the output of the second amplifier; the output of the fourth π-type attenuator is connected to the first mixer.

[0056] The second frequency conversion filter circuit includes: a second π-type attenuator connected to the output terminal of the second mixer, a fourth bandpass filter connected to the output terminal of the second π-type attenuator, a third π-type attenuator connected to the output terminal of the fourth bandpass filter, and a first low-pass filter connected to the output terminal of the third π-type attenuator.

[0057] Furthermore, the second local oscillator signal circuit includes:

[0058] The second phase-locked loop is configured to generate the second local oscillator signal;

[0059] The sixth bandpass filter has its input terminal connected to the output terminal of the second phase-locked loop;

[0060] The third amplifier is connected to the output of the sixth bandpass filter;

[0061] The fifth π-type attenuator has its input connected to the output of the third amplifier; the output of the fifth π-type attenuator is connected to the second mixer.

[0062] Based on the above circuit connections, the second mixer is connected to the output of the third bandpass filter. The first intermediate frequency signal after bandpass filtering is input to the second mixer. The second mixer mixes the signal with the second local oscillator to generate the second intermediate frequency signal. There is no cross-modulation spurious signal at the intermediate frequency end that falls into the band.

[0063] The second π-type attenuator is connected to the output of the second mixer to attenuate the mixed signal; the fourth bandpass filter is connected to the output of the second π-type attenuator to perform bandpass filtering on the 1995MHz second intermediate frequency signal, which can effectively suppress RF spurious signals with a suppression of better than 50dBc; the third π-type attenuator is connected to the output of the fourth bandpass filter to attenuate the output signal and prevent link mismatch.

[0064] The first low-pass filter is connected to the output of the third π-type attenuator to perform low-pass filtering on the output 1995MHz signal. By filtering out harmonics, it ensures that the harmonic suppression index meets the requirement of 50dBc and that the output standing wave ratio can reach 1.5.

[0065] The first local oscillator signal is generated by the first phase-locked loop (PLL) chip. The output of the first PLL is connected to the input of the fifth bandpass filter to perform bandpass filtering on the generated local oscillator signal. The output of the fifth bandpass filter is connected to the input of the second amplifier to amplify the local oscillator signal. The fourth π-type attenuator is connected to the output of the second amplifier to attenuate the amplified local oscillator signal, adjust the amplitude of the local oscillator signal to +5dBm, and then output the local oscillator signal to the LO port of the mixer.

[0066] The circuit for the second local oscillator signal is similar to that for the first local oscillator signal, with the main difference being the difference in the filtering frequency of the bandpass filter.

[0067] The frequency converter described in this patent also includes a reference frequency source module, which comprises modules such as a temperature-controlled crystal oscillator, a power divider, an amplifier, and a π-type attenuator. Figure 2 As shown, the reference frequency source module includes:

[0068] A temperature-controlled crystal oscillator; a fourth amplifier connected to the output of the temperature-controlled crystal oscillator; and a sixth π-type attenuator connected to the output of the fourth amplifier. The output of the sixth π-type attenuator is connected to a power divider, and the output of the power divider is connected in parallel to a seventh π-type attenuator and an eighth π-type attenuator. Correspondingly, the outputs of the seventh π-type attenuator and the eighth π-type attenuator are respectively connected to the first phase-locked loop of the first local oscillator signal circuit and the second phase-locked loop of the second local oscillator signal circuit.

[0069] The reference signal is generated by a temperature-controlled crystal oscillator. The output of the temperature-controlled crystal oscillator is connected to the input of the fourth amplifier to amplify the generated reference signal. The sixth π-type attenuator is connected to the output of the fourth amplifier to adjust the amplitude of the amplified signal. The input of the first power divider is connected to the output of the sixth π-type attenuator to split the reference signal into two reference signals. After the signal amplitude is adjusted by the seventh and eighth π-type attenuators, they are connected to the reference input of the phase-locked loop to provide a 50MHz reference signal for the phase-locked loop.

[0070] Finally, this invention provides a frequency converter that transforms the 2185MHz received signal to a 1995MHz transmitted signal. The interface between the microcontroller in the control unit and the external control program includes the microcontroller's serial communication port, which completes the output control of the local oscillator signal.

[0071] In summary, this embodiment discloses a frequency converter for converting a 2185MHz Tiantong received signal to a 1995MHz transmitted signal. The device has an external control program interface, wherein, under the joint control of the external control program and a microcontroller, through secondary frequency conversion and in conjunction with amplification and filtering circuits, the conversion of a 2185MHz received signal to a 1995MHz transmitted signal can be achieved. This embodiment is particularly suitable for testing equipment requiring a Tiantong satellite communication system.

Claims

1. An S-band frequency converter for testing equipment of the Tiantong satellite communication system, characterized in that, include: First mixer; The output terminals of the first bandpass filter and the first local oscillator signal circuit are both connected to the input terminal of the first mixer; The first frequency conversion filter circuit has its input terminal connected to the output terminal of the first mixer; The second mixer has its input connected to the output of the first frequency conversion filter circuit; The output terminals of the second local oscillator signal circuit are all connected to the input terminals of the second mixer; The input terminal of the second frequency conversion filter circuit is connected to the output terminal of the second mixer.

2. The S-band frequency converter for a Tiantong satellite communication system testing device according to claim 1, characterized in that, The first frequency conversion filter circuit includes: The first π-type attenuator is connected to the output terminal of the first mixer; The second bandpass filter is connected to the output of the first π-type attenuator; The first amplifier is connected to the output of the second bandpass filter; A third bandpass filter is connected to the output of the first amplifier.

3. The S-band frequency converter for a Tiantong satellite communication system testing device according to claim 1, characterized in that, The first local oscillator signal circuit includes: The first phase-locked loop is configured to generate the first local oscillator signal; The fifth bandpass filter has its input terminal connected to the output terminal of the first phase-locked loop; The second amplifier is connected to the output of the fifth bandpass filter; The fourth π-type attenuator has its input connected to the output of the second amplifier; the output of the fourth π-type attenuator is connected to the first mixer.

4. The S-band frequency converter for a Tiantong satellite communication system testing device according to claim 1, characterized in that, The second frequency conversion filter circuit includes: The second π-type attenuator is connected to the output terminal of the second mixer; The fourth bandpass filter is connected to the output of the second π-type attenuator; The third π-type attenuator is connected to the output of the fourth bandpass filter; The first low-pass filter is connected to the output of the third π-type attenuator.

5. The S-band frequency converter for a Tiantong satellite communication system testing device according to claim 1, characterized in that, The second local oscillator signal circuit includes: The second phase-locked loop is configured to generate the second local oscillator signal; The sixth bandpass filter has its input terminal connected to the output terminal of the second phase-locked loop; The third amplifier is connected to the output of the sixth bandpass filter; The fifth π-type attenuator has its input connected to the output of the third amplifier; the output of the fifth π-type attenuator is connected to the second mixer.

6. The S-band frequency converter for a Tiantong satellite communication system testing device according to claim 1, characterized in that, Also includes: Reference frequency source module; The reference frequency source module includes: Thermostatic crystal oscillator; The fourth amplifier has its input terminal connected to the output terminal of the thermostatic crystal oscillator; The sixth π-type attenuator is connected to the output of the fourth amplifier; A power divider, the input of which is connected to the output of the sixth π-type attenuator; The seventh π-type attenuator and the eighth π-type attenuator are connected in parallel to the output terminal of the power divider; the output terminals of the seventh π-type attenuator and the eighth π-type attenuator are respectively connected to the first local oscillator signal circuit and the second local oscillator signal circuit.

7. The S-band frequency converter for a Tiantong satellite communication system testing device according to claim 1, characterized in that, Also includes: An external control program interface is used to control the output of the local oscillator signal.

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