CN207530779U - A kind of mixting circuit - Google Patents

Abstract

The utility model is related to electronic measuring instrument field, more particularly to a kind of mixting circuit.The first frequency mixer that two paths of signals including being used to receive exports after being mixed, the output terminal of first frequency mixer pass sequentially through the first filter circuit, bandpass filter, the first low-pass filter, amplifier, the second low-pass filter and export to digital step attenuator；The output terminal of the amplifier is connect simultaneously by the second filter circuit with power supply.Mixting circuit provided by the utility model using digital stepping controlled attenuator, and passes through specific signal processing flow so that circuit work is more stablized, while export the radiofrequency signal in target zone.

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,

First frequency mixer, for exporting after the two paths of signals received is mixed；

The output terminal of first frequency mixer pass sequentially through the first filter circuit, bandpass filter, the first low-pass filter, Amplifier, the second low-pass filter are exported to digital step attenuator；

The output terminal of the amplifier is connect simultaneously by the second filter circuit with power supply.

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

Further, the bandpass filter is 1691MHz_BPF.

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 using digital stepping controlled attenuator, and passes through specific signal processing flow so that circuit works more Add stabilization, 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 be the utility model in the first frequency mixer, the first filter circuit, band pass filter circuit connection figure.

Fig. 3 is the first low-pass filter, amplifier, the second filter circuit connection figure in the utility model.

Fig. 4 is the second low-pass filter, digital step attenuator circuit connection diagram in the utility model.

Fig. 5 is the functional block diagram of front end mixting circuit in embodiment.

Fig. 6 is that front end mixting circuit intermediate-freuqncy signal source, third low-pass filter connect electricity with the first frequency mixer in embodiment Lu Tu.

Fig. 7 a are the first filtering and amplifying circuit circuit diagram in front end mixting circuit in embodiment.

Fig. 7 b are the second filtering and amplifying circuit circuit diagram in front end mixting circuit in embodiment.

Fig. 8 is radio-frequency switch circuit figure in front end mixting circuit in embodiment.

Fig. 9 is attenuator circuit figure in front end mixting 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 4, the present embodiment provides a kind of mixting circuit, including the first frequency mixer 1, this One frequency mixer 1 is used to after two paths of signals 2st Mixer and the 1520MHz signals received are mixed export；This implementation In example, the first frequency mixer uses RMS-30；The output terminal of first frequency mixer 1 passes sequentially through the first filter circuit 2, bandpass filter 3rd, the first low-pass filter 4, amplifier 5, the second low-pass filter 7 are exported to digital step attenuator 8, and export 1691BPF； The output terminal of the amplifier 5 is connect simultaneously by the second filter circuit 6 with+5Vam power supplys.

Specifically, in the present embodiment, the first filter circuit 2 is formed for tri- resistance of R21, R24, R25 of π type structures；Band Bandpass filter 3 uses 1691MHz_BPF；With signal ATT3, signal carries out attenuation control to digital step attenuator to rf wave in order to control System.

Wherein, signal 2st Mixer generate output, front end mixing electricity by front end mixting circuit as shown in Figures 5 to 9 Road is specific as shown in figure 5, including for generating the intermediate-freuqncy signal source 21 of 21.4MHz intermediate-freuqncy signals；Intermediate-freuqncy signal source 21 passes through Three low-pass filters 22 are connect with an input terminal of the second frequency mixer 23.

Another input terminal of second frequency mixer 23 receives 149.6MHz signals, which believes with 21.4MHz Number through the second frequency mixer 23 mixing after pass sequentially through the first filtering and amplifying circuit 24, the second filtering and amplifying circuit 25 after export 171MHz signals are to RF switch 26；In the present embodiment, the first filtering and amplifying circuit 24 includes sequentially connected first filtered electrical Road, the first amplifier and the first low-pass filter；First filter circuit is three resistance R18, R19, R20 of π type structures It forms；Second filtering and amplifying circuit 25 includes sequentially connected second amplifier and third low-pass filter 22.

The RF switch 26 is HMC536.The RF switch 26 receives at least two-way 171MHz signals, meanwhile, it is described The output terminal of RF switch 26 is connect with the first attenuator 27, and first attenuator 27 is by third low-pass filter by signal Output, the attenuator are voltage adjustable attenuator.As shown in figure 5, the access amplitude in this circuit mainly passes through the adjustable damping Device digital attenuation controls.

Claims (3)

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

First frequency mixer, for exporting after the two paths of signals received is mixed；

The output terminal of first frequency mixer passes sequentially through the first filter circuit, bandpass filter, the first low-pass filter, amplification Device, the second low-pass filter are exported to digital step attenuator；

The output terminal of the amplifier is connect simultaneously by the second filter circuit with power supply.

2. circuit as described in claim 1, which is characterized in that first filter circuit is three resistance structures of π type structures Into.

3. circuit as described in claim 1, which is characterized in that the bandpass filter is 1691MHz_BPF.