Differences

This shows you the differences between two versions of the page.

--- d2:offset_phase_lock_servo [2019/11/20 02:10] – [Front Panel] Michael Radunsky
+++ d2:offset_phase_lock_servo [2023/11/16 00:02] (current) – external edit 127.0.0.1
@@ Line 26: / Line 26: @@
 <imgcaption opls_schematic|Schematic of the D2-135 Offset Phase Lock Servo, D2-160 Beat Note Detector, and D2-150 Heterodyne Module>{{ :d2:d2-135:block_diagram.png?600|}}</imgcaption>
-A schematic of the OPLS, along with the [[d2:beat_note_detector|D2-160]] Beat Note Detector and [[d2:heterodyne_module|D2-150]] Heterodyne module is shown in <imgref opls_schematic>. The key component in the OPLS is a phase-frequency detector (PFD). The PFD compares the phase and frequency of the divided-by-N beat note to the reference frequency. The PFD outputs a signal proportional to the phase difference between the two input frequencies when there are no phase-slips between the two signals. This output provides a true phase-lock error signal. When there are phase slips, the PFD acts as a frequency comparator, aiding initial lock-up and enabling the OPLS to function as a //frequency//// ////offset//// ////lock// for laser sources with significant phase noise such as DFB and DBR laser diodes. The output of the PFD is fed to a charge pump and finally to the loop filter, where it is then fed back to the slave laser to control the frequency of the beat note.
+A schematic of the OPLS, along with the [[d2:beat_note_detector|D2-160]] Beat Note Detector and [[d2:heterodyne_module|D2-150]] Heterodyne module is shown in <imgref opls_schematic>. The key component in the OPLS is a phase-frequency detector (PFD). The PFD compares the phase and frequency of the divided-by-N beat note to the reference frequency. The PFD outputs a signal proportional to the phase difference between the two input frequencies when there are no phase-slips between the two signals. This output provides a true phase-lock error signal. When there are phase slips, the PFD acts as a frequency comparator, aiding initial lock-up and enabling the OPLS to function as a //frequency//// ////offset//// ////lock// for laser sources with significant phase noise. The output of the PFD is fed to a charge pump and finally to the loop filter, where it is then fed back to the slave laser to control the frequency of the beat note.
 The loop filter has user-adjustable proportional-integral-differential (PID) feedback and an additional high-frequency roll-off frequency. Tuning the values of the PID loop filter allows the user to optimize the feedback to the laser for best offset locks. This is further discussed below.
@@ Line 195: / Line 195: @@
 ====Right Side Panel ====
-<imgcaption opls_side_panel center|Schematic of the OPLS right-side panel,showing the configurable transfer functino and its user-controls.>{{ :d2:d2-135:d2-135-side-panel-f-for-freq.jpg?nolink&700 |}}</imgcaption>
+<imgcaption opls_side_panel center|Schematic of the OPLS right-side panel,showing the configurable transfer function and its user-controls.>{{ :d2:d2-135:d2-135-side-panel-f-for-freq.jpg?nolink&700 |}}</imgcaption>
 The feedback loop is defined by the Gain vs. Frequency plot shown above. ƒ<sub>I</sub>, ƒ<sub>D</sub> and ƒ<sub>HF</sub> define three corners in the transfer function. ƒ<sub>I</sub> is the frequency where the gain switches from having integral gain to having proportional gain. ƒ<sub>D</sub> is the frequency where the gain switches from proportional to differential. ƒ<sub>HF</sub> is the frequency where the gain begins to fall off at high frequency. ƒ<sub>I</sub>, ƒ<sub>D</sub>, and ƒ<sub>HF</sub> are each controlled by a rotary switch.
@@ Line 231: / Line 231: @@
 {{ :d2:d-sub_power_pinout.jpg?nolink&150 |}}
+While it is infrequent, the D2-005 power supply may occasionally radiate noise from the side of its chassis onto nearby electronics. This only occurs in some system configurations, and will appear as a signal at the frequency of your mains electricity (typically either 50 Hz or 60 Hz). This noise can easily be removed by moving the D2-005 at least 18 inches (45cm) away from other electronics, rotating it 90° such that the sides of the D2-005 face away, or by moving the entire power supply to a different shelf. To accommodate this, all D2-005's are shipped with a 5' DB9 cable as of January 1, 2022.
 **Computer Control (9-pin D-sub)**
@@ Line 261: / Line 264: @@
 <WRAP clear></WRAP>
+ \\
 **Ref. Freq. In**
@@ Line 281: / Line 284: @@
 **VCO Freq. Adjust**
-This input is summed in with the VCO TUNE potentiometer to set the voltage to the VCO, and thus the reference frequency when the OPLS is using the internal VCO. The impedance to this input in 1 kΩ and can accept voltages from -10V to +10V and should tune over entire VCO range, provided that the VCO TUNE potentiometer is set in the middle of the VCO range.
+This input is summed in with the VCO TUNE potentiometer to set the voltage applied to the VCO, and thus the reference frequency when the OPLS is using the internal VCO. The impedance of this input is 1 kΩ and it can accept voltages from -10V to +10V which will tune the reference frequency over the entire VCO range, provided that the VCO TUNE potentiometer is set in the middle of its range.
 =====Understanding Gain in the OPLS=====