N2PK VNA

From Note to self
Revision as of 02:42, 4 April 2014 by Hansvi (Talk | contribs) (Arduino interface)

(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search

Build notes

Master oscillator

I'm going to build the master oscillator from a Winner-Confield oscillator. Output needs to be adapted to 5V. -> Done, made a PCB

Parts

  • CW470CT-ND Winner Confield oscillator
  • TC1014-3.3VCT713CT-ND Microchip 3.3V Regulator
  • MMBTH10-FDICT-ND (.28€) of KST10MTFCT-ND (0.18€) -> First one has a much larger stock. Is there something I am missing about the cheaper model?
  • some caps and inductors for filtering 5V
  • some resistors

Documentation

Notes

  • The caps I bought
  • For the anti-aliasing filters I use the redesign (with 0.15uH inductors instead of 0.22uH, as the latter are not in stock at digi-key)

Components

Missing

Bottom side

  • R160a - R166a: I used 270k instead of 220k
  • C115-117,126,127: 10uF 16V X5R 1210
  • C180, C170: 27pF (filter redesign)
  • R250: 3.3R 5% 0805 - I have 1.8R, 3.9R -> Use 3.9
  • C250, 280,281,292: 10uF 16V Tant 20%
  • C213, C290 100nF X7R
  • C280,281,292

Top side

  • C251 100nF X7R
  • Q190,270: npn tx
  • C125: 1uF 25V X7R 10%

Questions

  • All caps seem to be NPO, X7R, X5R, or Tant. NPO = temperature independant, X7R & X5R = ceramic, Tant = tantalum. Problem: I only have an assortment, no other specs (prob. ceramic?)... According to Jacques, most small (pF) caps are NPO
  • R160a - R166a should be 221K. They are part of (what I assume to be) an RC filter, and a load for that filter (the input impedance of that buffer IC is probably quite high). These are digital lines. I don't have those values, so I was thinking about taking 1k2/75pF for the RC filter, and 270k for the load. I don't see why it should be very critical.
  • Build notes talk about using silver solder, this is not really necessary I presume.

Arduino interface

Interface Board Connections

Black 15 Ground
Orange 2 RF DDS data 
Purple 3 LO DDS Data
White 4 DDS W_Clk
Blue 5 DDS FQ_UD
Yellow 6 DDS Reset

Orange-red 7 ADC SCK
Brown 8 ADC nCS
Green 11 ADC nSDO (PIN IS INVERTED IN VNA!!!)

javascript charting

Mailing list: interesting messages

3539 (!), 4482, 4457, 6164 (PSU), 3452 (!)