Gain filter circuit applicable to scientific-grade CCDs

Abstract

The invention provides a gain filter circuit applicable to scientific-grade CCDs (charge coupled device), in particular to the processing circuit of CCDs. The gain filter circuit comprises an operational amplifier, two analog switches (S1 and S2), a resistor (R) and a capacitor (C), wherein the analog switch S2 is connected with the capacitor (C) in parallel to jointly form the negative feedback of the operational amplifier; the non-inverting input terminal of the operational amplifier is grounded, and the inverting input terminal thereof is connected with the output signal of the CCD via the resistor (R); and the output signal of the CCD is grounded via the other analog switch (S1). Followed by the start of the driving circuit of the CCD, the gain filter circuit can continuously adjust the amplification of the circuit on a real-time basis by adjusting and feeding back the disconnection time of the analog switch (S2) according to the driving timing sequence of the CCD; and by adjusting the capacitance of the capacitor (C) and the resistance of the resistor (R), the gain filter circuit can vary the amplification within a large range and vary the cutoff frequency of the circuit, thus achieving the low-pass filter on the output signals of the CCD. Accordingly, based on the simple control, the invention can achieve the continuously adjustable gain and the filter function.

Description

technical field [0001] The invention relates to the design of a control circuit of a camera, in particular to a design of a gain filter circuit applied to a scientific grade CCD. Background technique [0002] When performing astronomical observations, sometimes it is necessary to adjust the gain of the camera according to the radiation intensity of different observation targets, so that the dynamic range of the camera can be fully utilized for targets with different radiation intensities to obtain clear images, or for the same observation target, by adjusting the camera Gain, to observe the details of areas with different radiation intensities, and enhance the contrast of local images. At the same time, astronomical observation cameras all need filter circuits to obtain low-noise images. The currently used controllable gain circuit is implemented in two ways, one is to directly apply a programmable gain amplifier, and the other is to use a combination of an analog switch an...

AI Technical Summary

Problems solved by technology

With the increasing application of astronomical observation cameras in space, due to the limitation of satellite resources, it is hoped that the camera can achieve gain adjustment in a simple and reliable way, and the shortcomings of the above circuit structure are becoming more and more obvious

Images