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Message ID: 1893     Entry time: Fri Jan 15 10:57:39 2021
Author: Paco 
Type: Lab Infrastructure 
Category: EquipmentLoan 
Subject: Borrow AG4395A and EOM Driver TF re-tune 

See equipment borrowing note here.

Attempting TF measurement for resonant EOM driver, but not having luck reproducing the measurements done recently (Dec-03), so I started debugging the circuit. Both power supply connections (+- 18 VDC) seem nominal. The MAX2470 buffer regulated input is nominal at 5VDC. Looking at MMBT5551 HF transistor, base-emitter voltage is -0.60 VDC (nominal wrt -0.66 V). Using a scope, I feed a single tone (36 MHz, 190 mVpp) and look at the RFmon output and it looks ok (gain ~ 1). I changed the RFmon SMA cable and that seemed to do the trick... Bad cable (now in trash) stole my morning.

Tune EOM driver resonance to 35.993 MHz (shown below for reference).

Attachment 1: EOMDriver_TF_Inp_to_RFMon_CloseUp_15-01-2021_160402.pdf  31 kB  Uploaded Fri Jan 15 16:07:35 2021  | Show | Hide all | Show all
Attachment 2: EOMDriver_TF_Inp_to_RFMon_Wide_15-01-2021_151039.pdf  32 kB  Uploaded Fri Jan 15 16:07:49 2021  | Hide | Hide all | Show all
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