Difference between revisions of "Colpitts Crystal Oscillator"

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[[file:Colpitts_Osc_P1780-720px.jpg]]
+
[[file:CP-OSC_BNC_Rev2-720px.jpg]]
  
 
== Features ==
 
== Features ==
  
 
* Colpitts Crystal Oscillator
 
* Colpitts Crystal Oscillator
* Useful for binning crystals
+
* Useful for binning crystals for use in [[Crystal Filter Design|building crystal filters]]
** Hand select close values from a pile of crystals
+
** Hand select close crystal frequency values from a pile of crystals
** Useful for [[Crystal Filter Design|design of crystal filters]]
 
 
* Made from junk box parts
 
* Made from junk box parts
 
** (2) 2N3904 transistors
 
** (2) 2N3904 transistors
Line 15: Line 14:
 
** May run at higher voltages, didn't tempt fate
 
** May run at higher voltages, didn't tempt fate
 
* 15mA with 4.44 MHz crystal at 12V
 
* 15mA with 4.44 MHz crystal at 12V
 +
** 18 mA at 14V
 +
 +
=== Schematic ===
 +
 +
[[file:CP_Osc_Schematic_Rev2.PNG]]]
  
== Tested With ==
+
=== Tested With ===
  
 
* 4.433 MHz crystal - worked
 
* 4.433 MHz crystal - worked
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== Prototype ==
 
== Prototype ==
  
 +
[[file:Colpitts_Osc_P1780-720px.jpg]]
 
* Cut square PCB material for raised pads
 
* Cut square PCB material for raised pads
* Build on single side Copper clad PCB material
+
* Build on single sided Copper clad PCB material
 
* Large ground plane
 
* Large ground plane
  
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== tinySA Measurements of SMT Build ==
 
== tinySA Measurements of SMT Build ==
  
* SMT build
+
=== SMT build - Rev 1 ===
 +
 
 
* 12V power
 
* 12V power
 
* 4.43 MHz crystal
 
* 4.43 MHz crystal
* Measured +8.6dBm into 50 ohm load
+
* Measured +8.6 dBm into 50 ohm load
 
* 40 dBm attenuator to protect tinySA
 
* 40 dBm attenuator to protect tinySA
 
* [[Frequency Counter 8 Digits|8 Digits Frequency Counter]] shows 4.432298 MHz
 
* [[Frequency Counter 8 Digits|8 Digits Frequency Counter]] shows 4.432298 MHz
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* 5V Operation
 
* 5V Operation
 +
* +4.3 dBm
  
 
[[file:CP_Osc__4p43MHz_4_to_10MHz__5V_SMT_tinySA.PNG]]
 
[[file:CP_Osc__4p43MHz_4_to_10MHz__5V_SMT_tinySA.PNG]]
 +
 +
=== SMT build - Rev 2 ===
 +
 +
[[file:CP-OSC_BNC_Rev2-720px.jpg]]
 +
 +
* 12V power
 +
* 4.43 MHz crystal
 +
* Measured +7.56 dBm into 50 ohm load
 +
* 20 dBm attenuator to protect tinySA
 +
* BNC connector
 +
 +
[[file:CP_Osc_4p43MHz_4_to_30MHz_SMT_BNC_Rev2_tinySA.PNG]]
 +
 +
* SMA connector
 +
 +
[[file:CP-OSC_SMA_Rev2-720px.jpg]]
 +
 +
[[file:CP_Osc_4p43MHz_4_to_30MHz_SMT_SMA_Rev2_tinySA.PNG]]
  
 
== W2AEW Video ==
 
== W2AEW Video ==
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[[file:XTAL-Osc-3.PNG]]
 
[[file:XTAL-Osc-3.PNG]]
  
== PCB - Rev 2 -3D ==
+
<video type="youtube">I4bAfDu6F1k</video>
 
 
[[file:CP-OSC-3D-Rev2_720px.png]]
 
  
 
== Assembly Sheet ==
 
== Assembly Sheet ==
  
 
[[Colpitts XTAL Oscillator Rev 1 Assembly Sheet]]
 
[[Colpitts XTAL Oscillator Rev 1 Assembly Sheet]]
 +
 +
[[Colpitts XTAL Oscillator Rev 2 Assembly Sheet]]

Latest revision as of 00:16, 13 October 2021

CP-OSC BNC Rev2-720px.jpg

Features

  • Colpitts Crystal Oscillator
  • Useful for binning crystals for use in building crystal filters
    • Hand select close crystal frequency values from a pile of crystals
  • Made from junk box parts
    • (2) 2N3904 transistors
    • Standard value 1/4W resistors
  • Design from Experimental Methods in RF Design - Fig 7.69
    • Built by others (W2AEW, IMSAIGuy, etc)
  • Runs from 4V to >16V
    • May run at higher voltages, didn't tempt fate
  • 15mA with 4.44 MHz crystal at 12V
    • 18 mA at 14V

Schematic

CP Osc Schematic Rev2.PNG]

Tested With

  • 4.433 MHz crystal - worked
  • 16 MHz crystal - worked
  • 27 MHz crystal - didn't work

Prototype

Colpitts Osc P1780-720px.jpg

  • Cut square PCB material for raised pads
  • Build on single sided Copper clad PCB material
  • Large ground plane

XTAL-Osc-5-720px.jpg

Scope Caps

  • UUT = 4.4433 MHz crystal
  • 8 Digits Frequency Counter shows 4.432285 MHz
  • Rigol DS1054Z - 50 MHz scope (100 MHz mod)
  • UltraScope
  • Waveform triangular

Prototype

XTAL-Osc-UltraScope-01.PNG

SMT Build

CP Osc 4p43MHz Rigol HiZ In.png]

tinySA Measurements of SMT Build

SMT build - Rev 1

  • 12V power
  • 4.43 MHz crystal
  • Measured +8.6 dBm into 50 ohm load
  • 40 dBm attenuator to protect tinySA
  • 8 Digits Frequency Counter shows 4.432298 MHz

CP Osc 4p43MHz SMT tinySA.PNG

  • 4 to 30 MHz scan
  • Rich even and odd harmonic content
  • -60 dBm down outside of harmonics

CP Osc 4p43MHz 4 to 30MHz SMT tinySA.PNG

  • 4 to 100 MHz

CP Osc 4p43MHz 4 to 100MHz SMT tinySA.PNG

  • 5V Operation
  • +4.3 dBm

CP Osc 4p43MHz 4 to 10MHz 5V SMT tinySA.PNG

SMT build - Rev 2

CP-OSC BNC Rev2-720px.jpg

  • 12V power
  • 4.43 MHz crystal
  • Measured +7.56 dBm into 50 ohm load
  • 20 dBm attenuator to protect tinySA
  • BNC connector

CP Osc 4p43MHz 4 to 30MHz SMT BNC Rev2 tinySA.PNG

  • SMA connector

CP-OSC SMA Rev2-720px.jpg

CP Osc 4p43MHz 4 to 30MHz SMT SMA Rev2 tinySA.PNG

W2AEW Video

  • Wes Haywood EMiRFD circuit

XTAL-Osc.PNG

XTAL-Osc-2.PNG

XTAL-Osc-3.PNG

Assembly Sheet

Colpitts XTAL Oscillator Rev 1 Assembly Sheet

Colpitts XTAL Oscillator Rev 2 Assembly Sheet