They are designed with a phase-locked-loop control system, for rock solid control. They may also be controlled with and external controller if desired thorough the RS232 port.. This allows the chopping rate to also be synchronized to a user-supplied external clock.
The chopper heads are attached to the controller by means of a 10 foot coiled cord. The precision etched blade is fully enclosed for protection from inadvertent damage with the closed chopper head.
The C995 Optical Chopper is equipped with a bi-directional RS-232 port that permits the user to set the desired chopping rate to a resolution of .001 Hz and to read the status of the instrument.
There are two apertures on the chopper head and two sections on the blade for the high and low frequency ranges. The aperture diameter is 15 mm with a slot width of 4.5 mm for the 30 slot section and 30 mm for 3 slot section. The small 4.75 inch square outline and two inch maximum depth of the chopper head permits easy integration into compact optical setups. Dual #8-32 mounting holes permit the apertures to be placed at a height as low as 0.75 inches above an optical bench, or with the included 1/2 inch rod and stand, as high as 13 inches above the mounting surface.
The standard units are supplied with a 3/30 blade offering the 4 Hz to 5000 Hz operation. Also available are the 1 slot blade for operation at rate of 1.3333 Hz to 166.66 Hz and the 2/10 slot blade for operation at rates of 2.6666 Hz to 333.33 Hz when set to low and when set at the high rate, 13.333 Hz to 1666.6 Hz.
