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d2:offset_phase_lock_servo [2019/05/24 08:40]
Michael Radunsky [Offset Phase Lock Servo]
d2:offset_phase_lock_servo [2020/03/05 17:51] (current)
Michael Radunsky [Right Side Panel]
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 The D2-135 comes in two different versions: The D2-135 comes in two different versions:
  
-  *//​D2-135-SMA ​//SMA input of the electrical beat-note+  *//​D2-135-SMA//​ SMA input of the electrical beat-note
   *//​D2-135-FC-800//​ - Fiber-input of optical beat-note for wavelengths 750nm - 870nm (obsolete)   *//​D2-135-FC-800//​ - Fiber-input of optical beat-note for wavelengths 750nm - 870nm (obsolete)
  
 The D2-135-SMA requires an electrical signal input between 10 and -10 dBm of power. ​ The D2-135-SMA requires an electrical signal input between 10 and -10 dBm of power. ​
  
-The D2-135-FC-800 is no longer available, but information regarding it is retained for those users who have purchased this model. ​ It includes a 10 GHz GaAs high-speed photo-detector for converting the input optical beat-note into a electrical beat-note. The maximum optical input power is 1 mW. //Warning: input powers ​ over 1mW of optical power can damage the OPLS.//  A minimum of 50 μW of power in the optical beat-note is required(( Note the power in the beat-note is not the same as total power. Because the optical input uses multi-mode fiber, the spatial mode overlap between the two lasers is not guaranteed. If the overlap between the two lasers is poor, there can be very little power in the beat-note despite large optical power. )).+The D2-135-FC-800 is no longer available, but information regarding it is retained for those users who have purchased this model. ​ It includes a 10 GHz GaAs high-speed photo-detector for converting the input optical beat-note into a electrical beat-note. The maximum optical input power is 1 mW. //Warning: input powers ​ over 1mW of optical power can damage the internal photodetector.//  A minimum of 50 μW of power in the optical beat-note is required(( Note the power in the beat-note is not the same as total power. Because the optical input uses multi-mode fiber, the spatial mode overlap between the two lasers is not guaranteed. If the overlap between the two lasers is poor, there can be very little power in the beat-note despite large optical power. )).
 ===== Absolute Maximum Ratings ===== ===== Absolute Maximum Ratings =====
 Note: All modules designed to be operated in laboratory environment Note: All modules designed to be operated in laboratory environment
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 =====Modes===== =====Modes=====
  
-The OPLS operates in 12 different modes, controlled by the front-panel knob or with external inputs to the back-panel. These 12 modes select the value of the divide-by-N (N=8,16,32, or 64) and select between three states for the reference frequency (external input, internal VCO High, internal VCO Low).  The table below shows the offset frequency ranges for these 12 different modes.+The OPLS operates in 12 different modes, controlled by the front-panel knob or with external inputs to the back-panel. These 12 modes select the value of the divide-by-N (N=8, 16, 32, or 64) and select between three states for the reference frequency (external input, internal VCO High, internal VCO Low).  The table below shows the offset frequency ranges for these 12 different modes.
  
 <WRAP center round box 70%> <WRAP center round box 70%>
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 ^ ^^  N=8  ^  N=16  ^  N=32  ^  N=64  ^ ^ ^^  N=8  ^  N=16  ^  N=32  ^  N=64  ^
 ^  Reference \\ Frequency \\ Setting ​ ^External |250 - 1,920|480 - 3,840|960 - 7,680|1,920 - 10,000| ^  Reference \\ Frequency \\ Setting ​ ^External |250 - 1,920|480 - 3,840|960 - 7,680|1,920 - 10,000|
-^:::​^External Reference Input Frequency |30 - 240||||+^:::​^External Reference Input Frequency |30 - 240 MHz||||
 ^:::​^Internal VCO Low |385 - 850|770 - 1,700|1,540 - 3,400|3,080 - 6,800| ^:::​^Internal VCO Low |385 - 850|770 - 1,700|1,540 - 3,400|3,080 - 6,800|
 ^:::​^Internal VCO High |770 - 1,700|1,540 - 3,400|3,080 - 6,800|6,160 - 10,000| ^:::​^Internal VCO High |770 - 1,700|1,540 - 3,400|3,080 - 6,800|6,160 - 10,000|
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 ===Error Signal (AC)=== ===Error Signal (AC)===
  
-This is an unfiltered version of  Error Signal (DC) that is four times smaller, and has a DC offset. ​ When phase locked, the output is 1.6V+2.8<​sup>​mv</​sup>/<​sub>​deg</​sub>​*θ,​ where θ is the phase-error in degrees. When in frequency mode, the output is 1.6V±1V*(1-f<​sub>​small</​sub>/​(2 f<​sub>​big</​sub>​)).+This is an unfiltered version of  Error Signal (DC) that is four times smaller, and has a DC offset. ​ When phase locked, the output is 1.6V+2.8<​sup>​mV</​sup>/<​sub>​deg</​sub>​*θ,​ where θ is the phase-error in degrees. When in frequency mode, the output is 1.6V±1V*(1-f<​sub>​small</​sub>/​(2 f<​sub>​big</​sub>​)).
  
 ===Ref Freq=== ===Ref Freq===
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 **Coarse Gain (eight-position switch)** **Coarse Gain (eight-position switch)**
  
-The COARSE GAIN sets the overall proportional gain of the circuit without changing the location of any corners or poles in the loop filter transfer function. The coarse gain adjusts in steps of 6 dB from 0 dB to -42 dB.+The COARSE GAIN sets the overall proportional gain of the circuit without changing the location of any corners or poles in the loop filter transfer function. The coarse gain adjusts in steps of 6 dB from 0 dB to -76 dB.
  
 **Servo Output** **Servo Output**
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 ====Right Side Panel ==== ====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. 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.
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 =====Calculating Phase Noise ===== =====Calculating Phase Noise =====
  
-The phase-noise specified in Section 1.3 is referenced to the phase frequency detector (PFD) at 1 Hz. To convert that to the noise measured on the actual beat-note, it must be rescaled with the following formula:+The phase-noise specified in the [[d2:​offset_phase_lock_servo#​specifications|Specifications]] above is referenced to the phase frequency detector (PFD) at 1 Hz. To convert that to the noise measured on the actual beat-note, it must be rescaled with the following formula:
  
 ''​D2-135 Phase-Noise Floor = -213 + 20Log(N) + 10Log(F<​sub>​REF</​sub>​)''​ ''​D2-135 Phase-Noise Floor = -213 + 20Log(N) + 10Log(F<​sub>​REF</​sub>​)''​
  
  
-where N is the value of the divider and F<​sub>​REF</​sub>​ is the reference frequency as measured in Hz. For more details, please see [[http://​www.vescent.com/​2012/​calculating-phase-noise-from-the-d2-135/​|http://​www.vescent.com/​2012/​calculating-phase-noise-from-the-d2-135/]] .+where N is the value of the divider and F<​sub>​REF</​sub>​ is the reference frequency as measured in Hz. For more details, please see [[http://​www.vescent.com/​2012/​calculating-phase-noise-from-the-d2-135/​|Calculating Phase Noise from the D2-135]].
  
 =====Help ===== =====Help =====
d2/offset_phase_lock_servo.1558712403.txt.gz · Last modified: 2019/05/24 08:40 by Michael Radunsky