# HG changeset patch # User David Douard # Date 1518713808 -3600 # Node ID 9ba7fe3d0a226c1a4e047e309b25886afce1df73 # Parent aa1c62f7951894c7771442da3484fcaf5329164c [eip545B] part 3: few improvements about digits resolution diff -r aa1c62f79518 -r 9ba7fe3d0a22 content/eip545b_3.rst --- a/content/eip545b_3.rst Fri Jan 26 23:32:39 2018 +0100 +++ b/content/eip545b_3.rst Thu Feb 15 17:56:48 2018 +0100 @@ -54,7 +54,7 @@ read the whole content of the RAM via GPIB. It's very slow, since I did not find a way using GPIB commands to read 2 memory -addresses without quitting the TEST10 mode between to reads. And I had to add +addresses without quitting the TEST10 mode between two reads. And I had to add several sleep() since the EIP is pretty slow to respond to GPIB commands. A complete dump of the 2ko RAM took somethin like 15 or 20 minutes. @@ -133,8 +133,20 @@ for the Frequency Offset, which I haven't done yet (I was waiting for a cheap EPROM eraser from eb, which just arrived). -Now I also want to fix the initial resolution setup, which I haven't figured -out yet. +Concerning the resolution, some clue can be found just after the previous +routine:: + + 6125 LDX #M005D ;8E 00 5D + 6128 LDA #$0D ;86 0D + 612A STA $01,X ;A7 01 + 612C LDA #$05 ;86 05 + 612E STA >M0045 ;B7 00 45 + +In which the value 0x0D is written at RAM address 0x005E (0x005D + 0x01 from +the opcode ``STA $01,X``), and the value 0x05 is written at RAM address 0x0045, +which we identified previously as a candidate for the digits resolution +setting; pretty consistant with the 0x05 value written there. Not sure what the +0x0D is used for at address 0x005E. The sensitivity problem @@ -163,7 +175,7 @@ On the bottom side, we can see the YIG spheres and the coupling loops: -.. image:: {filename}images/eip545b/yig_bottomn.jpg +.. image:: {filename}images/eip545b/yig_bottom.jpg :alt: Top view of the YIG filter So this filter consists in a 2 stage bandpass filter (with input and output @@ -193,8 +205,8 @@ HighPrecision), we'll see if it works. I hope it's a 127MHz version, otherwise I'll have to replace the YIG filter (A201) on my A203 unit with this one. -By the way, for thoses interested, I found these 2 documents interesting to -begin to understand how a YIG oscillator and a YIG filter works: +By the way, for thoses interested, I found these 2 simple documents interesting +to begin to understand how a YIG oscillator and a YIG filter works: - `YIG TUNED OSCILLATORS`_ - `YIG TUNED FILTERS`_