CN204721315U - VCO tuning slope Circuit tuning - Google Patents

Abstract

The utility model discloses a kind of VCO tuning slope Circuit tuning, comprise operational amplifier, the first resistance, the second resistance, the 3rd resistance, the 4th resistance and the 5th resistance; Wherein, the first resistance is connected with the end in the same way of operational amplifier, with the 3rd resistant series after the second resistance first resistor coupled in parallel; The other end ground connection of the 3rd resistance; 4th resistance one end is connected with the backward end of operational amplifier, other end ground connection; 5th resistance one end is connected with the backward end of operational amplifier, and the other end is connected with the output of operational amplifier.The utility model circuit structure is simple, and cost is low.

Description

VCO tuning slope Circuit tuning

Technical field

The utility model relates to signal transacting field, particularly relates to a kind of VCO tuning slope Circuit tuning.

Background technology

Voltage controlled oscillator (VCO) is the important component part of radio circuit.Important role is played the part of in the fields such as VCO has just communicated since it is born always, electronics, navigation Aero-Space and medical science, and tool has been widely used.Especially, in communication system circuit, VCO is its critical component, such as, in radar module, the performance of 24GHz Continuous Wave with frequency modulation (FMCW) and the fm linearity of voltage controlled oscillator (VCO) closely related; Main application process is: VCO produces the fixing Continuous Wave with frequency modulation of a tuning slope, and this electromagnetic wave to front by antenna transmission, is run into barrier back reflection and returns, and receives the radio frequency reception channel to 24GHz transceiving chip by antenna; The transmitted wave receiving electromagnetic wave and the current time of returning carries out mixing, then produce an intermediate-freuqncy signal; Baseband processing circuitry calculates the information such as distance, speed of preceding object thing by parameters such as tuning slope, control voltage cycle, IF-FRE.

Existing VCO chip is designed to able to programme and fixed value two kinds to tuning slope, and for the programmable VCO chip of tuning slope, user can adjust tuning slope by application configuration.For the VCO chip that tuning slope is fixing, due to service life and environmental factor, when causing its tuning slope to need to adjust, but cannot adjust, need to look for chip producer to customize the chip met the demands, to cause product only due to VCO chip tuning slope problem scrapping or need again to change VCO, high cost like this.

Utility model content

The purpose of this utility model is, there is provided a kind of VCO tuning slope Circuit tuning, to improve fixing VCO chip tuning slope (tuning slope refers to the output frequency variable quantity of voltage controlled oscillator under unit change voltage) the nonadjustable problem of tuning slope.

The utility model discloses a kind of VCO tuning slope Circuit tuning, foregoing circuit comprises operational amplifier, the first resistance, the second resistance, the 3rd resistance, the 4th resistance and the 5th resistance; Wherein, above-mentioned first resistance is connected with the end in the same way of above-mentioned operational amplifier, with above-mentioned 3rd resistant series after above-mentioned first resistor coupled in parallel of above-mentioned second resistance; The other end ground connection of above-mentioned 3rd resistance; Above-mentioned 4th resistance one end is connected with the backward end of above-mentioned operational amplifier, other end ground connection; Above-mentioned 5th resistance one end is connected with the backward end of above-mentioned operational amplifier, and the other end is connected with the output of above-mentioned operational amplifier.

Preferably, above-mentioned first resistance is slide rheostat.

The utility model circuit structure is simple, and making does not need to change chip or the custom chip just adjustable existing tuning slope fixing the VCO chip of tuning slope, and cost is low.

Accompanying drawing explanation

Accompanying drawing described herein is used to provide further understanding of the present utility model, forms a part of the present utility model, and schematic description and description of the present utility model, for explaining the utility model, is not formed improper restriction of the present utility model.In the accompanying drawings:

Fig. 1 is VCO tuning slope Circuit tuning first embodiment schematic diagram described in the utility model;

Fig. 2 is VCO tuning slope Circuit tuning second embodiment schematic diagram described in the utility model.

Embodiment

In order to make technical problem to be solved in the utility model, technical scheme and beneficial effect clearly, understand, below in conjunction with drawings and Examples, the utility model is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the utility model, and be not used in restriction the utility model.

As shown in Figure 1, be VCO tuning slope Circuit tuning first embodiment schematic diagram described in the utility model; In figure, foregoing circuit comprises operational amplifier A m, the first resistance R1, the second resistance R2, the 3rd resistance R3, the 4th resistance R4 and the 5th resistance R5; Wherein, the first resistance R1 is connected with the end in the same way of operational amplifier A m, and the second resistance R2 connects with the 3rd resistance R3 with after the first resistance R1 parallel connection; The other end ground connection of the 3rd resistance R3; 4th resistance R4 one end is connected with the backward end of operational amplifier A m, other end ground connection; 5th resistance R5 one end is connected with the backward end of operational amplifier A m, and the other end is connected with the output of operational amplifier A m; In figure, Vo is output voltage, and V1 is External Control Voltage; V2 is built-in DC offset voltage, and for producing a reference voltage at output, reference voltage is determined by VCO chip controls voltage range (0.5V ~ 5V);

According to Fig. 1, make Rp=R1*R2/ (R1+R2);

Rn＝R4*R5/(R4+R5)；

Then:

Vo＝(Rp/Rn)*R5*(V1/R1+V2/R2)；

As known from the above, as R1=29k Ω, R2=6k Ω, R3=1k Ω, R4=20k Ω, R5=4k Ω, Vo ≈ V1/30+V2/6.Visible, as V2=3V and V1=0 time, Vo=0.5V; V1 changes 1V, Vo and changes 1/30V;

Such as, suppose the input voltage range of the voltage controling end of VCO chip requires to be 0.5 ~ 5V, and its tuning slope is 1500MHz/V; But the tuning slope of user's actual need is 50MHz/V, now, R1=29k Ω, R2=6k Ω, R3=1k Ω, R4=20k Ω, R5=4k Ω, because output voltage Vo connects the voltage control pin of VCO chip, the External Control Voltage range mappings that then can realize 0 ~ 5V, to 0.5 ~ 0.667V output voltage range, finally realizes the requirement of 50MHz/V tuning slope.That is, in fact VCO tuning slope Circuit tuning described in the utility model is exactly an in-phase proportion amplifier.

As shown in Figure 2, be VCO tuning slope Circuit tuning second embodiment schematic diagram described in the utility model; The difference of Fig. 2 and Fig. 1 is, the first resistance R1 is slide rheostat; The present embodiment according to the different demands of user, by adjusting the resistance of the first resistance R1, can obtain different tuning slopes.

Above-mentioned explanation illustrate and describes preferred embodiment of the present utility model, but as previously mentioned, be to be understood that the utility model is not limited to the form disclosed by this paper, should not regard the eliminating to other embodiments as, and can be used for other combinations various, amendment and environment, and can in utility model contemplated scope described herein, changed by the technology of above-mentioned instruction or association area or knowledge.And the change that those skilled in the art carry out and change do not depart from spirit and scope of the present utility model, then all should in the protection range of the utility model claims.

Claims (2)

1. a VCO tuning slope Circuit tuning, is characterized in that, described circuit comprises operational amplifier, the first resistance, the second resistance, the 3rd resistance, the 4th resistance and the 5th resistance; Wherein, described first resistance is connected with the end in the same way of described operational amplifier, with described 3rd resistant series after the first resistor coupled in parallel described in described second resistance; The other end ground connection of described 3rd resistance; Described 4th resistance one end is connected with the backward end of described operational amplifier, other end ground connection; Described 5th resistance one end is connected with the backward end of described operational amplifier, and the other end is connected with the output of described operational amplifier.

2. VCO tuning slope Circuit tuning as claimed in claim 1, it is characterized in that, described first resistance is slide rheostat.