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d2:laser_servo

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d2:laser_servo [2020/07/28 12:13]
Michael Radunsky [Back-panel Section]
d2:laser_servo [2020/07/28 12:18] (current)
Michael Radunsky [Back-panel Section]
Line 328: Line 328:
 **Relative Jump TTL (BNC)** **Relative Jump TTL (BNC)**
  
-When asserted HIGH (5 V) while in LOCK mode, RELATIVE JUMP engages a sample-and-hold circuit and takes the Laser Servo out of lock. The voltage on the SERVO OUTPUT is the sample-and-hold value summed in with <color black/yellow>the negative</color> of the LASER JUMP AMPLITUDE. For example, if the laser is locked and the SERVO OUTPUT is -200 mV, then putting <color black/yellow>+</color>300 mV on the LASER JUMP AMPLITUDE and engaging the RELATIVE JUMP will set the SERVO OUTPUT to -200 mV + (<color black/yellow>-</color>300 mV) = -500 mV.  This feature is useful for jumping the laser relative to its current lock point (say +200 MHz from a locked transition). When returned to LOW (0 V), the loop filter is reengaged, enabling the laser to be relocked to its original position (by setting LASER JUMP AMP to zero before returning the trigger to TTL low), or to a new lock point (by asserting the trigger low with the LASER JUMP AMP still at a non-zero value). (See [[http://www.vescent.com/jumping-lock-point-d2-125-reconfigurable-servo/|application note here]].) Engaging or disengaging the RELATIVE JUMP is achieved in under 400 μs.+When asserted HIGH (5 V) while in LOCK mode, RELATIVE JUMP engages a sample-and-hold circuit and takes the Laser Servo out of lock. The voltage on the SERVO OUTPUT is the sample-and-hold value summed in with <color black/yellow>the negative</color> of the LASER JUMP AMPLITUDE. For example, if the laser is locked and the SERVO OUTPUT is -200 mV, then putting <color black/yellow>+</color>300 mV on the LASER JUMP AMPLITUDE and engaging the RELATIVE JUMP will set the SERVO OUTPUT to -200 mV + (<color black/yellow>-</color>300 mV) = -500 mV.  This feature is useful for jumping the laser relative to its current lock point (say +200 MHz from a locked transition). When returned to LOW (0 V), the loop filter is reengaged, enabling the laser to be relocked to a new lock point (by asserting the trigger low with the LASER JUMP AMP still at a non-zero value). (See [[http://www.vescent.com/jumping-lock-point-d2-125-reconfigurable-servo/|application note here]].)  Or the laser can be relocked to its original position (by setting LASER JUMP AMP to zero before returning the trigger to TTL low). Engaging or disengaging the RELATIVE JUMP is achieved in under 400 μs.
  
 When asserted HIGH (5V) while in RAMP mode, RELATIVE JUMP applies a DC offset equal to the LASER JUMP AMPLITUDE to the ramp signal at SERVO OUTPUT. When asserted LOW (0V) while in RAMP mode, the ramp signal is DC balanced. When asserted HIGH (5V) while in RAMP mode, RELATIVE JUMP applies a DC offset equal to the LASER JUMP AMPLITUDE to the ramp signal at SERVO OUTPUT. When asserted LOW (0V) while in RAMP mode, the ramp signal is DC balanced.
d2/laser_servo.txt · Last modified: 2020/07/28 12:18 by Michael Radunsky