Physical setup
Measuring transimpedance amplifier by itself.
[1] Actual Board S/N SN 02
[2] In-vac "QPD" Enclosure S/N S2100832
[3] Transimpedance Circuit Schematic D2000592

Now using D2200215 whitening chassis as a much more convenient user interface.
Don't have to power down the whitening or DPCDs to connect or disconnect at all, so thermal state should be quite stable.

Now using
	Connecting SR785 differential drive BNCs to clip-doodles to DB9 breakout pins 1(neg)-6(pos) (with shield connected to chassis GND pin 5), into "From AI/DAC" DB9 port in the back of the D2200215 chassis.

	Connecting SR785 response comes from the preamp output monitoe BNC spigots at the front of the D2200215 chassis, "A+" to CH2 A "A-" to CH2 B.

ONCE ALL TURN THE ANALOG RELAYS FOR THE DCPDs ON.


SR785 Setup (by hand, didn't want to waste time figuring out GPIB setup)

Freq
	Repeat: Single Shot (don't continuously repeat sweep once done)
	Start: 102.4 kHz 
	Stop: 0.1 Hz 
	Type: Log (log-spaced frequency vector)
	# of points: 200
	Auto Res.: OFF

Display Options
	Display: Live
	Format: Dual
	RPM Frequency: OFF
	Grid: ON
	Grid Div: 10
	Phase Suppress: 0.0e+00
	d/dx window (%): 0.5

Display Setup
	TOP TRACE
	Measure Group: Swept Sine
	Measurement: Freq. Resp
	View: Linear (Magnitude, i.e. not in dB)
	Units: 
		dB Units: OFF
		Pk. Units: OFF
		Phase Units: deg
		dBm. ref impedance: 50

	BOTTOM TRACE
	Measure Group: Swept Sine
	Measurement: Freq. Resp
	View: Phase
	Units:
		dB Units: OFF
		Pk. Units: OFF
		Phase Units: deg
		dBm Ref. Impedance: 50
	
Source
	Auto Level Ref: OFF
	Amplitude: 1.0 V_pk
		

	Source Ramp Rate 1 V/sec, but
	Source Ramping OFF
	Offset 0.0 V 

Input Setup 
	Input Source: Analog
	Input Config:
		CH 1 (Both Channels)
		Mode: A-B (positive legs into A, negative legs into B)
		Coupling: DC	(AC coupling filter is at 0.16 Hz, and we're measuring to 0.1 Hz, so we don't want to be impacted by the response of this filter.)
		AA filter ON
		Wt filter OFF
		Autorange UP ONLY

		Input Range (for 4.0 V source amplitude, 50 ms / 5 cycle integration):
		CH1: +14 dBVpk
		CH2: +16 dBVpk

		Input Range (for 1.0 V source amplitude, 50 ms / 5 cycle integration):
		CH1: +2 dBVpk
		CH2: +4 dBVpk

	Transducer Params: (all as default; unused in this style of measurement)
	Tach Input: (all as default; unused in this style of measurement)
	Playback Config: (all as default; unused in this style of measurement)
	Auto Offset OFF
		
Average Setup
	Settle Time = 100 ms (101.56 ms)
	Settle Cycles = 1
	Integration Time = 916 ms (101.781 ms)
	Integration Cycles = 5 
with freq = [0.1 102.4e3] and 200 points, this takes 465 seconds = 8 minutes

Output
	Hard Copy Button ASCII Dump
	Bitmap Printer PC X 8 Bit
	Bitmap Area Graphs
	Vector / Plotter PostScript (doesn't matter, unused)
	Destination Disk File
	File Start Number 0
	

NOW GET Measurement test setup.
First time doing this, so let's explore.

(1) Add DB25 breakout board between DCPD input cable and Whitening Chassis.
    Connect DAC Drive (DUT + and - from SR785 Accessory Box) into
	DCPDA + signal pin 5 shield 13
	      - signal pin 18 shield 13

	DCPDB + signal pin 1 shield 13
	      - signal pin 14 shield 13

    Leave response drive connected via normal BNC outputs as above.

    and *RECONNECT AND POWER BACK ON* the DCPD preamp.

This ended at ~12:15 pm PST

(2) Same set up, but POWER DOWN DCPD preamp (since (i) you've already got the fully thermalized preamp measurement above, and it's not involved in the "setup" measurement, it's OK to let the preamp "unthermalize").

At 12:45, we disconnected the DB25 breakout and re-powered on the DCPD preamps.
At 12:50 we took, in parallel a DAC driven measurement of *just* the preamp.
	Whitening OFF
	Relay ON
	Compensation for Whitening and TIA (and A2mA) OFF.
Data saved to 
    /ligo/svncommon/CalSVN/aligocalibration/trunk/Common/Electronics/H1/SensingFunction/OMCA/

(3) Just measure the SR785 accessory box alone, hooking DUT + - into channels into CH2 of the SR785. (the SR785 + and -) are still connected to CH1 of SR785.