# HG changeset patch
# User Daniel O'Connor <darius@dons.net.au>
# Date 1359593689 -37800
# Node ID fa728cf34f509d2ffcd22c0b04193fc86e1d4a61
# Parent  a6e5c97b476714e26fc7679daf945fbf8a30567a
- Calculate ENR (based on table on the back of our noise source)
- Accept options to set frequency, span, etc
- Actually call the setup routine

diff -r a6e5c97b4767 -r fa728cf34f50 rs_fsp7_noisetest.py
--- a/rs_fsp7_noisetest.py	Thu Dec 20 11:48:19 2012 +1030
+++ b/rs_fsp7_noisetest.py	Thu Jan 31 11:24:49 2013 +1030
@@ -26,11 +26,30 @@
 #
 
 import math
+import numpy
+import optparse
 import rsib
+import scipy
 import scpi
 import sys
 
-def setup(r):
+def findenr(frq):
+    # ENR values from the noise source
+    enrdb = numpy.array([15.55, 15.96, 15.68, 15.11, 15.07, 14.84, 14.77, 14.82, 14.86, 14.79, 14.83, 14.93, 14.93, 15.07, 15.19, 15.08, 15.14, 14.87, 14.97, 14.59])
+    enrfrq = numpy.array([0.01e9, 0.1e9, 1.0e9, 2.0e9, 3.0e9, 4.0e9, 5.0e9, 6.0e9, 7.0e9, 8.0e9, 9.0e9, 10.0e9, 11.0e9, 12.0e9, 13.0e9, 14.0e9, 15.0e9, 16.0e9, 17.0e9, 18.0e9])
+
+    # Convert back to linear values
+    enr = 10 ** (enrdb / 10)
+
+    # Interpolate
+    rtn = scipy.interp([frq], enrfrq, enr)
+
+    # Convert to dB
+    rtndb = 10 * math.log10(rtn)
+
+    return rtndb
+    
+def setup(r, freq, span, sweeps):
     # Reset to defaults
     r.write("*RST")
 
@@ -41,7 +60,8 @@
     r.write("SYST:DISP:UPD ON")
 
     # Set frequency range
-    r.write("FREQ:CEN 10.7MHz;SPAN 1MHz")
+    r.write("SENSE1:FREQ:CENT %f Hz" % (freq))
+    r.write("SENSE1:FREQ:SPAN %f Hz" % (span))
 
     # Switch marker 1 on in screen A
     r.write("CALC:MARK1 ON")
@@ -50,13 +70,13 @@
     r.write("CALC:MARK1:FUNC:NOIS ON")
 
     # Set number of sweeps
-    r.write("SWE:COUN 20")
+    r.write("SWE:COUN %d" % (sweeps))
 
     # Set resolution bandwidth
-    r.write("SENS1:BAND:RES 10kHz")
+    r.write("SENS1:BAND:RES 1kHz")
 
     # Set video bandwidth (10x res BW)
-    r.write("SENS1:BAND:VID 100kHz")
+    r.write("SENS1:BAND:VID 10kHz")
     
 def getnoise(r):
     # Trigger the sweep
@@ -105,19 +125,43 @@
     return off, on, calcnf(enr, off, on)
 
 if __name__ == '__main__':
-    enr = 15.55 # From back of noise source
-    r = rsib.RSIBDevice('analyzer')
+    parser = optparse.OptionParser(usage = '%prog [options] address frequency')
+    parser.add_option('-s', '--span', dest = 'span', default = 1e6, help = 'Span frequency (Hz)', type = float)
+    parser.add_option('-i', '--input', dest = 'input', default = None, help = 'Input frequency (Hz) for down converters', type = float)
+    parser.add_option('-w', '--sweeps', dest = 'sweeps', default = 20, help = 'Number of sweeps', type = int)
+
+    (options, args) = parser.parse_args()
+
+    if len(args) != 2:
+        parser.error('Must supply the specan address and centre frequency')
+
+    addr = args[0]
+    try:
+        freq = float(args[1])
+    except ValueError:
+        parser.error('Unable to parse frequency')
+
+    if options.input == None:
+        options.input = freq
+
+    # Compute ENR at frequency of interest
+    enr = findenr(options.input)
+
+    # Connect to the analyser
+    r = rsib.RSIBDevice(addr)
 
     # ID instrument
     r.write('*IDN?')
     print "ID is " + r.read(5)
 
-    #setup(r)
+    # Setup parameters
+    setup(r, freq, options.span, options.sweeps)
+
     r.write("INIT:CONT OFF")
 
     while True:
         off, on, nf = donoisetest(r, enr)
-        print "Off %.3f dB, on %.3f dB, NF %.2f" % (off, on, nf)
+        print "Off %.3f dB, on %.3f dB, ENR %.2f, NF %.2f" % (off, on, enr, nf)
         print "Press enter to perform a new measurement"
         sys.stdin.readline()