more change log notes as I build #2

git-svn-id: https://svn.code.sf.net/p/freetel/code@1818 01035d8c-6547-0410-b346-abe4f91aad63

diff --git a/smartmic/README b/smartmic/README
index b574f174b14a8a8edea7ea2f99038c5701372460..364882d46c62b994d1ea5be51278ee5ce27d04e0 100644 (file)
--- a/smartmic/README
+++ b/smartmic/README
@@ -34,4 +34,4 @@ Directories
 SM1000-PCB  First pass design that was never manufactured but used to collect
             review comment
 SM1000-B1   Prototype SM1000, small qty of PCBs made and hand loaded
-SM1000-C    Beta SM1000   
+SM1000-B2    Beta SM1000   

diff --git a/smartmic/SM1000-REV-B2/Change-Log-B2.txt b/smartmic/SM1000-REV-B2/Change-Log-B2.txt
index 233a506ef5ce0190be9f3e9ce8d3ceeb3758ce83..24fd22817a0bbb301682059b4a22ff4740278168 100644 (file)
--- a/smartmic/SM1000-REV-B2/Change-Log-B2.txt
+++ b/smartmic/SM1000-REV-B2/Change-Log-B2.txt
@@ -122,7 +122,7 @@ Latest change notes David 14 August
     + and connectors and TP, hard to see with naked eye\r
 [ ] foot print for a small reset button\r
     + I press it a lot, gd for experimenting\r
-[ ] 220pF to filter noise across 500k R42 but very close to op-amp\r
+[ ] 1nF to filter noise across 500k R42 but very close to op-amp\r
 [ ] highly senstive net between R53 and R42 should be shorter if possible, \r
     as we are getting a lot of noise pick up.\r
 [ ] Move ADC power supply bypass network v close to pins 21/22 U1B and\r
@@ -140,3 +140,34 @@ Latest change notes David 14 August
     + investigate this in simulation form\r
 [ ] check trimmers all go the same way around\r
 [ ] connect C36 to + term of U6, delete R43\r
+[ ] some gain on U6 a good idea?\r
+    + laptop audio ouput just a few 100mVpp\r
+    + at least put in resistors.\r
+[ ] very big robust pads for R46\r
+    + pot keeps falling off, breaking pads\r
+[ ] Consider case made from PCB, like sniffers\r
+    + can get all holes drilled\r
+    + gd RF shielding\r
+[ ] should square pad on Mic be gnd side?\r
+[ ] added 3n9 between U8 p3 and ground \r
+    + removed some tonal noise and \r
+[ ] changed R39 to 2k2\r
+    + mic bias now 2.8V\r
+[ ] Switcher noise reduction idea\r
+    + is there away to lock the switcher osc to a uC clock?\r
+    + we could make it a multiple of ADC/DAC sample rate\r
+    + thus aliasing all noise down to 0 Hz\r
+    + need swicther to freerun until uC starts\r
+[ ] review jumpers and see if it makes mores sense to make them 0 ohm 0805s\r
+[ ] C24 closer to U1?\r
+[ ] C40 should be 47nF\r
+    + David used wrong value on prototype\r
+[ ] LD2 opto-isolator footprint wrong (or maybe I ordered wrong part) \r
+[ ] location of C51 net label\r
+[ ] SW1 needs bigger pads to make hand solderable\r
+    + is this suitable as a PTT switch?\r
+    + button is quite small\r
+    + locking PTT as per SW3 useful for testing (want to leave tx on)\r
+[ ] CN12 is hard to solder manually, need larger mechanical pads\r
+    + although this would increase the outline so maybe not a problem\r
+[ ] CN2 difficult to hand solder, extend padds back towards outline\r