project: tracking generator synchronisation device

[kirill_ka]

The basic idea is to use the RFExplorer signal generator as a tracking generator for HP8561E.
Although my current implementation is built around the devices I possess, the idea can be extended for other spectrum analysers and/or signal generators. I plan to gradually release the implementation details for the case someone would find it interesting or even want to reuse my approach.

Block diagram

Code: [Select]

+-----------------+        +-----------------+       +----------------+
|RFE Generator    |        | Synchronisation |       | HP 8561E       |
|                 |        | Thing           |       |                |
|                 |        |                 |       +------------+   |
|                 |        |                 |       |85620 module|   |
|                 |        |        SPI Slave|-------|GPIO/SBIT   |   |
|                 |        |                 |       +------------+   |
|                 |        |            GATE |-------|GATE (not used) |
|             USB |--------| USB Host    SWP |-------|AUX Sweep out   |
|                 |    ----| 5V power    FAV |-------|Sweep out/FAV   |
|                 |   /    +-----------------+       |                |
|                 |  |                               |                |
|           RF OUT|-------- [DUT] -------------------|INPUT           |
+-----------------+  |                               +----------------+
                     |
                    Optional
                    5V power
                    supply


[kirill_ka]

Tracking generator control/alignment UI
All the configuration is done through the custom menu on the HP8561E.
This adds some convenience by not requiring a PC. Also there's some fun in programming 8561E in it's archaic language.

The main "user keys" menu.


Sweep alignment menu. Also shows the generator swept across 6GHz.


Native tracking generator menu & normalised trace.

[kirill_ka]

Hardware
The hardware is built round the ATMega 348P microcontroller and the MAX3421E USB host controller. For now I'm using a couple of slightly modified of-the-shelf boards. The MAX3421E board is an Arduino shield, but I'm not using it as a shield. That's because the SPI slave interface (which is normally connected to the MAX3421E) is needed to communicate with the 85620 module. An easier way could be to use some Linux-based board, but I suspect I wouldn't be able to get precise timing from Linux. Also I want to be able to power it from the 85620 which only provides 150mA @5V.

The whole thing is fitted into the shell of a dead LiPo charger.