CN207475490U

CN207475490U - A kind of mixting circuit

Info

Publication number: CN207475490U
Application number: CN201721702178.6U
Authority: CN
Inventors: 向东红; 何兴凤
Original assignee: Chengdu Chiffo Electronics Instruments Co Ltd
Current assignee: Chengdu Chiffo Electronics Instruments Co Ltd
Priority date: 2017-12-08
Filing date: 2017-12-08
Publication date: 2018-06-08
Anticipated expiration: 2027-12-08

Abstract

The utility model is related to electronic measuring instrument field, more particularly to a kind of mixting circuit.Including intermediate-freuqncy signal source, for generating 21.4MHz intermediate-freuqncy signals；The intermediate-freuqncy signal source is connect by the first low-pass filter with an input terminal of the first frequency mixer；Another input terminal of first frequency mixer receives 149.6MHz signals, which exports 171MHz signals to RF switch after passing sequentially through the first filtering and amplifying circuit, the second filtering and amplifying circuit after the mixing of the first frequency mixer with 21.4MHz signals；The RF switch receives at least two-way 171MHz signals, meanwhile, the output terminal of the RF switch is connect with the first attenuator, and first attenuator is exported signal by third low-pass filter；Mixting circuit provided by the utility model, work are more stablized.

Description

A kind of mixting circuit

Technical field

The utility model is related to electronic measuring instrument field, more particularly to a kind of mixting circuit.

Background technology

In radiofrequency signal field, electronic gauge is essential test equipment, and the signal source in electronic gauge The even more core devices of electronic gauge are mainly responsible for generation with specific frequency, the radio signal of amplitude, if letter If number source is the core devices of electronic gauge, then mixting circuit is exactly the core circuit of signal source, the spy of mixting circuit Property directly determine that can signal source generate qualified signal.

Utility model content

The purpose of this utility model is that needing the technical need of stable mixting circuit in face of good signal source, one is provided Kind is used for the mixting circuit of electronic gauge signal source.

In order to realize above-mentioned purpose of utility model, the utility model provides following technical scheme：

A kind of mixting circuit, including,

Intermediate-freuqncy signal source, for generating 21.4MHz intermediate-freuqncy signals；

The intermediate-freuqncy signal source is connect by the first low-pass filter with an input terminal of the first frequency mixer；

Another input terminal of first frequency mixer receives 149.6MHz signals, the 149.6MHz signals and 21.4MHz Signal passes sequentially through output 171MHz letters after the first filtering and amplifying circuit, the second filtering and amplifying circuit after the mixing of the first frequency mixer Number to RF switch；

The RF switch receives at least two-way 171MHz signals, meanwhile, the output terminal of the RF switch declines with first Subtract device connection, first attenuator is exported signal by third low-pass filter, which is voltage adjustable attenuator.

Further, first filtering and amplifying circuit include sequentially connected first filter circuit, the first amplifier and First low-pass filter.

Further, first filter circuit is formed for three resistance of π type structures.

Further, second filtering and amplifying circuit includes sequentially connected second amplifier and the second low-pass filtering Device.

Compared with prior art, the beneficial effects of the utility model：The utility model provides a kind of for electronic gauge The mixting circuit of signal source, by specific signal processing flow, and applied voltage adjustable attenuator so that circuit works more Stablize, while export the radiofrequency signal in target zone.

Description of the drawings：

Fig. 1 is the functional block diagram of the utility model.

Fig. 2 is that intermediate-freuqncy signal source, the first low-pass filter connect circuit diagram with the first frequency mixer in the utility model.

Fig. 3 a are the first filtering and amplifying circuit circuit diagram in the utility model.

Fig. 3 b are the second filtering and amplifying circuit circuit diagram in the utility model.

Fig. 4 is radio-frequency switch circuit figure in the utility model.

Fig. 5 is attenuator circuit figure in the utility model.

Fig. 6 is Post Mixer schematic block circuit diagram in embodiment.

Fig. 7 is the first frequency mixer, the first filter circuit, band pass filter circuit connection in Post Mixer circuit in embodiment Figure.

Fig. 8 is the second low-pass filter, amplifier, the second filter circuit connection figure in Post Mixer circuit in embodiment.

Fig. 9 is third low-pass filter, digital step attenuator circuit connection diagram in Post Mixer circuit in embodiment.

Specific embodiment

Below in conjunction with the accompanying drawings and specific embodiment is described in further detail the utility model.But this should not be understood Range for the above-mentioned theme of the utility model is only limitted to following embodiment, all technologies realized based on the utility model content Belong to the scope of the utility model.

Embodiment 1：As shown in Figures 1 to 5, the present embodiment provides a kind of mixting circuit, including for generating 21.4MHz The intermediate-freuqncy signal source 1 of intermediate-freuqncy signal；Intermediate-freuqncy signal source 1 passes through the first low-pass filter 2 and an input terminal of the first frequency mixer 3 Connection.

Another input terminal of first frequency mixer 3 receives 149.6MHz signals, the 149.6MHz signals and 21.4MHz signals Output 171MHz believes after the first filtering and amplifying circuit 4, the second filtering and amplifying circuit 5 are passed sequentially through after the mixing of the first frequency mixer 3 Number to RF switch 6；In the present embodiment, the first filtering and amplifying circuit 4 includes sequentially connected first filter circuit, the first amplification Device and the first low-pass filter；First filter circuit is formed for three resistance R18, R19, R20 of π type structures；This implementation In example, the second filtering and amplifying circuit 5 includes sequentially connected second amplifier and the second low-pass filter.

The RF switch 6 receives at least two-way 171MHz signals, meanwhile, the output terminal and first of the RF switch 6 Attenuator 7 connects, and first attenuator 7 is exported signal by third low-pass filter, which, which is that voltage is adjustable, declines Subtract device, the attenuator is HSMP-3814.As shown in figure 5, the access amplitude in this circuit mainly adjusts 7 numbers of decaying by first Word is decayed, end 20dBm gains control.Cal_amp is that the maximum voltage of control electricity tune attenuation is about 3.2V or so electric at this time Adjust attenuation minimum, voltage reduces attenuation increase, and cal_amp voltage 0.8V when, which decays, is close to 20dBm, finally output letter Number signal 2st Mixer.

The signal 2st Mixer of the present embodiment output are finally by Post Mixer circuit as shown in Figures 6 to 9 Reason, the Post Mixer circuit include, the second frequency mixer 21, which is used for the two paths of signals 2st that will be received Mixer and 1520MHz signals export after being mixed；In the present embodiment, the second frequency mixer 21 uses RMS-30；First mixing The output terminal of device 21 passes sequentially through the first filter circuit 22, bandpass filter 23, the second low-pass filter 24, amplifier 25, Three low-pass filters 27 are exported to digital step attenuator 28, and export 1691BPF；The output terminal of the amplifier 25 leads to simultaneously The second filter circuit 26 is crossed to connect with+5Vam power supplys；In a particular embodiment, the first filter circuit 22 for π type structures R21, Tri- resistance of R24, R25 are formed；With signal ATT3, signal carries out adjustable attenuation to rf wave in order to control for it.

Claims

1. a kind of mixting circuit, which is characterized in that including,

Another input terminal of first frequency mixer receives 149.6MHz signals, the 149.6MHz signals and 21.4MHz signals 171MHz signals are exported after the first filtering and amplifying circuit, the second filtering and amplifying circuit are passed sequentially through after the mixing of the first frequency mixer extremely RF switch；

The RF switch receives at least two-way 171MHz signals, meanwhile, the output terminal of the RF switch and the first attenuator Connection, first attenuator are exported signal by third low-pass filter；The attenuator is voltage adjustable attenuator.

2. circuit as described in claim 1, which is characterized in that first filtering and amplifying circuit includes sequentially connected first Filter circuit, the first amplifier and the first low-pass filter.

3. circuit as claimed in claim 2, which is characterized in that first filter circuit is three resistance structures of π type structures Into.

4. circuit as described in claim 1, which is characterized in that second filtering and amplifying circuit includes sequentially connected second Amplifier and the second low-pass filter.