The taut band resonant chopper (optical modulator) is a FIXED FREQUENCY
electromechanically driven vane which reflects or blocks a light beam via a sinusoidal motion. This chopper is used when excursion cannot be attained with a tuning fork chopper and very low frequencies (down to 5 Hz) are desired. The chopper operates at one fixed frequency chosen from the chopping range of 5 Hz to 300 Hz. The practical upper frequency is 100 Hz. Taut band
choppers are used for chopping large diameter beams and for sequentially chopping a pair of parallel beams (up to 0.6 inch in diameter). The amplitude of the motion of the chopper is inversely proportional to its frequency. Dark or bright vanes are standard, but can be replaced with a mirror to create a beam deflector. Filters or gratings are optional as well. Optical devices such as detectors and emitters may be attached to the vanes with fine conductors.
Either the ED driver or the AGC driver is used to drive the CH-30 taut band chopper. The AGC driver also provides high amplitude stability (0.005%) and both sine and TTL reference signals.
Special vane configurations, modulating waveforms and shapes are available as a special order (consult EOPC). Drive electronics with different package, regulation and power supply options are available. Special pricing is also available for OEM applications.
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The following should serve as guide lines only:
FREQUENCY
(Hz) |
ANGULAR MOTION (at top of vane)
(P-P Degrees) |
W (width)
(Inches) |
L (length)
(Inches) |
D (beam dia.)
(Inches) |
6.5 |
30 |
1.00 |
1.50 |
0.60 |
13 |
30 |
1.00 |
1.50 |
0.60 |
25 |
30 |
0.78 |
1.25 |
0.60 |
40 |
25 |
0.78 |
1.00 |
0.40 |
100 |
15 |
0.30 |
0.40 |
0.30 |
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ORDERING INFORMATION:
TYPE [CH-30]; VANE [B=bright or D=dark]; FREQUENCY [Hz]; VANE SIZE [W,L]; ANGULAR MOTION [P-P Deg.]
Example: PART NO. CH30-D-200-1×1.5-30. This part number specifies the model CH-30 chopper, dark vanes and a 200 Hz operating frequency, 1 inch vane width × 1.5 inch vane length and 30° peak to peak angular motion.
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