comparison: content/10MHz_ref_2.rst
content/10MHz_ref_2.rst
- changeset 43
- 4c3a05ba94de
- child 115
- 6b6e13653348
equal
deleted
inserted
replaced
| 42:3c30fc0f8ce0 | 43:4c3a05ba94de |
|---|---|
| 1 ========================================== | |
| 2 Building a bench 10MHz reference: part 2 | |
| 3 ========================================== | |
| 4 | |
| 5 :author: David Douard | |
| 6 :Category: Electronics | |
| 7 :Tags: test equipment, 10MHz, Rubidium | |
| 8 :series: 10MHz Bench Reference Standard | |
| 9 :series_index: 2 | |
| 10 | |
| 11 This is a quick follow-up of the `first part`_ of this series. | |
| 12 | |
| 13 I've received a few parts from digikey, including a couple of 22µH | |
| 14 Sumida CLS62 inductors (I bought two of them in case I f**k up one of | |
| 15 them trying to solder it with my Weller WS50 iron). | |
| 16 | |
| 17 Desoldering and soldering SMD parts without an air flow station is a | |
| 18 bit tricky, but eventually I succeded in replacing the broken inductor. | |
| 19 | |
| 20 .. image:: {filename}/images/freq_ref/extron_fixed.jpg | |
| 21 :alt: The Extron Video Distribution Amplifier fixed with a | |
| 22 new inductor for its small DC-DC converter. | |
| 23 | |
| 24 Now the "video" amplifier works like a charm. The 10MHz signal is | |
| 25 nicely amplified: | |
| 26 | |
| 27 .. image:: {filename}/images/freq_ref/extron_working_10MHz.jpg | |
| 28 :alt: The Extron Video Distribution Amplifier dispatching a | |
| 29 10MHz signal to several equipments. | |
| 30 | |
| 31 At 10Mhz, the amplifier dephase the signal of about 20ns (ie. 72 | |
| 32 deg). We can also note that (the input impedance of the Extron | |
| 33 amplifier is set to 75 ohm, while my scope is at 1 Mohm; I should try | |
| 34 using the input of my scope set at 50ohm) that the amplification | |
| 35 factor is exactly x2. | |
| 36 | |
| 37 .. image:: {filename}/images/freq_ref/extron_dephasing_10MHz.jpg | |
| 38 :alt: The Extron Video Distribution Amplifier dephasing at 10MHz. | |
| 39 | |
| 40 What I need to check carefully now is if all the outputs of the | |
| 41 amplifier are perfectly in phase. | |
| 42 | |
| 43 It's amusing that a few days ago, FlyingHacker_ did post a `new thread | |
| 44 on the EEVBlog`_ forum in which he explain that he uses exactly the | |
| 45 same distribution amplifier to provide a 10MHz reference to several | |
| 46 test equipments. Exactly what I have in mind with mine! | |
| 47 | |
| 48 One thing I will probably not do is adapting the input/output | |
| 49 impedance (from 75 ohm to 50 ohm). I'm pretty sure it will work fine | |
| 50 as is. We'll see if it provoque some side effects (especioally on the | |
| 51 phase of the signal). | |
| 52 | |
| 53 .. _FlyingHacker: http://www.eevblog.com/forum/profile/?u=110591 | |
| 54 .. _`new thread on the EEVBlog`: http://www.eevblog.com/forum/projects/distribution-amp-%28for-reference-frequency-standard-or-otherwise%29/msg893851/ | |
| 55 | |
| 56 | |
| 57 .. _`first part`: {filename}/10MHz_ref.rst |
