################################################################################
                    Summary Project TBASEDSB021121
################################################################################

o General setup:

C-band receiver (both linear polarizations)
IF rack optical fiber channels 2 and 3 (ch 4 was removed)
Converter modules 1 and 5
Sampler filters 1 and 5
Spectrometer mode 1W2-001-800 (2048 channels, 800 MHz BW)

o IF noise source:

Scan 7 consists of 60, 30 sec integrations with the IF noise source.
Then antenna was stationary.  Figures 1a and 1b show (Sig - Ref)/Ref for
receiver 1 and 2, respectively.  Reciever 1 corresponds to optical
fiber channel 2 and receiver 2 to optical fiber channel 3.  For each
spectrum the Sig correspond to consecutive records while the Ref is
always record 1.  The red lines correspond to records 2-10, green to
records 11-20, blue to records 21-30, cyan (blue/green) to records
31-40, magenta (red/blue) to records 41-50, and yellow to records
51-60.  Two hundred channels have been dropped from the beginning and
end of each spectrum.  The average value of (Sig - Ref)/Ref is plotted
as a function of record number in Figure 1c.

Overall the spectra are reasonably flat with a drift +/- 1% of the
system temperature over 30 minutes.  Receiver 2 seems to drift less
than receiver 1.  Although a ripple appears near record 20 for
receiver 2 with an amplitude of ~0.2% and frequency of ~70 MHz (see
Figure 2).

The theoretical noise (RMS/Tsys) is 0.000510 assuming an 800 MHz
bandwidth, an effective integration time of 15 seconds, and a sampling
efficiency of 1.235.  Below is a list of measured standard deviations
using channels 201-1848.

Ref Sig rcvr   rms
--- --- ---- --------
1   2   1    0.000527
1   2   2    0.000514
1   10  1    0.000556
1   10  2    0.000557
1   20  1    0.000645
1   20  2    0.000637
1   30  1    0.000621
1   30  2    0.000587
1   40  1    0.000599
1   40  2    0.000589
1   50  1    0.000579
1   50  2    0.000602
1   60  1    0.000586
1   60  2    0.000600
---------------------


o Cold sky:

Scan 6 consists of 60, 30 sec integrations with the antenna stationary
and pointed towards cold sky.  A similar analysis was done as with the
IF noise source.  Figures 3a and 3b show (Sig - Ref)/Ref for receiver 1
and 2, respectively.  Overall the receiver 1 data seem to drift more
than receiver 2 but the baseline shape is flatter with receiver 1.

Below is a list of measured standard deviations using channels
201-1848.  Note there is some interference in receiver 2 which will
increase the rms.

Ref Sig rcvr   rms
--- --- ---- --------
1   2   1    0.000710
1   2   2    0.000775   
1   10  1    0.000721
1   10  2    0.000794
1   20  1    0.000792
1   20  2    0.000865
1   30  1    0.000915  
1   30  2    0.000889
1   40  1    0.00106
1   40  2    0.000982
1   50  1    0.000975
1   50  2    0.00109
1   60  1    0.000982
1   60  2    0.00121
---------------------


o Cold sky onoff:

Scans 10,11 consist of an onoff pair where both positions are towards
cold sky for 5 minutes each at the same hour angle.  Figure 4 plots
Tsys/Tcal for reciever 1 (red) for scans 10 and 11, and for receiver 2
(green) for scans 10 and 11.  The Tsys does not significantly change
between the on and off scans.  All 10 records have been averaged.  A
~68 MHz ripple is present in the Tsys/Tcal data.

The Ta/Tsys plot is shown in Figure 5.  An ~48 MHz ripple persist in
the processed data for receiver 1 (red) and an ~73 MHz ripple in
receiver 2 (green).  Plotting (Sig-Ref)/Ref for the CAL OFF phase
(phase=2) produces similar results (see Figure 6).

o Continuum source onoff:

Scans 12-17 consist of three onoff pairs towards sources with
different continuum intensities.  Figures 7, 8, and 9 plot Ta/Tsys
for increasing continuum intensity for receiver 1 (red) and receiver 2
(green).  In all cases the ripple persists.