From: drowe67 Date: Wed, 27 Aug 2014 09:23:27 +0000 (+0000) Subject: more change log notes as I build #2 X-Git-Url: http://git.whiteaudio.com/gitweb/?a=commitdiff_plain;h=104c778b594304ad1dce902ccffc913238f60cfb;p=freetel-svn-tracking.git 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 b574f174..364882d4 100644 --- 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 233a506e..24fd2281 100644 --- 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 [ ] foot print for a small reset button + I press it a lot, gd for experimenting -[ ] 220pF to filter noise across 500k R42 but very close to op-amp +[ ] 1nF to filter noise across 500k R42 but very close to op-amp [ ] highly senstive net between R53 and R42 should be shorter if possible, as we are getting a lot of noise pick up. [ ] Move ADC power supply bypass network v close to pins 21/22 U1B and @@ -140,3 +140,34 @@ Latest change notes David 14 August + investigate this in simulation form [ ] check trimmers all go the same way around [ ] connect C36 to + term of U6, delete R43 +[ ] some gain on U6 a good idea? + + laptop audio ouput just a few 100mVpp + + at least put in resistors. +[ ] very big robust pads for R46 + + pot keeps falling off, breaking pads +[ ] Consider case made from PCB, like sniffers + + can get all holes drilled + + gd RF shielding +[ ] should square pad on Mic be gnd side? +[ ] added 3n9 between U8 p3 and ground + + removed some tonal noise and +[ ] changed R39 to 2k2 + + mic bias now 2.8V +[ ] Switcher noise reduction idea + + is there away to lock the switcher osc to a uC clock? + + we could make it a multiple of ADC/DAC sample rate + + thus aliasing all noise down to 0 Hz + + need swicther to freerun until uC starts +[ ] review jumpers and see if it makes mores sense to make them 0 ohm 0805s +[ ] C24 closer to U1? +[ ] C40 should be 47nF + + David used wrong value on prototype +[ ] LD2 opto-isolator footprint wrong (or maybe I ordered wrong part) +[ ] location of C51 net label +[ ] SW1 needs bigger pads to make hand solderable + + is this suitable as a PTT switch? + + button is quite small + + locking PTT as per SW3 useful for testing (want to leave tx on) +[ ] CN12 is hard to solder manually, need larger mechanical pads + + although this would increase the outline so maybe not a problem +[ ] CN2 difficult to hand solder, extend padds back towards outline