--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rs_fsp7_noisetest.py	Thu Dec 20 11:48:19 2012 +1030
@@ -0,0 +1,123 @@
+#!/usr/bin/env python
+
+# Copyright (c) 2012
+#      Daniel O'Connor <darius@dons.net.au>.  All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+
+import math
+import rsib
+import scpi
+import sys
+
+def setup(r):
+    # Reset to defaults
+    r.write("*RST")
+
+    # Set to single sweep mode
+    r.write("INIT:CONT OFF")
+
+    # Enable display updates
+    r.write("SYST:DISP:UPD ON")
+
+    # Set frequency range
+    r.write("FREQ:CEN 10.7MHz;SPAN 1MHz")
+
+    # Switch marker 1 on in screen A
+    r.write("CALC:MARK1 ON")
+
+    # Enable noise measurement
+    r.write("CALC:MARK1:FUNC:NOIS ON")
+
+    # Set number of sweeps
+    r.write("SWE:COUN 20")
+
+    # Set resolution bandwidth
+    r.write("SENS1:BAND:RES 10kHz")
+
+    # Set video bandwidth (10x res BW)
+    r.write("SENS1:BAND:VID 100kHz")
+    
+def getnoise(r):
+    # Trigger the sweep
+    r.write("INIT;*WAI")
+
+    # Wait for it to be done
+    r.write("*OPC?")
+    opc = scpi.getdata(r.read(60), int)
+    #print "OPC - %d" % (opc)
+    assert(opc == 1)
+    
+    # Set data format
+    r.write("FORM:DATA ASC")
+
+    # Read noise value
+    r.write("CALC:MARK1:FUNC:NOIS:RES?")
+    data = r.read(10)
+    #print "Data - " + data
+
+    return float(data)
+
+def setnoise(r, en):
+    if en:
+        val = "ON"
+    else:
+        val = "OFF"
+    r.write("DIAG:SERV:NSO " + val)
+
+def calcnf(enrdb, offdb, ondb):
+    # Not possible but weak results may give it
+    if ondb <= offdb:
+        return 0
+    ydb = ondb - offdb
+    y = 10 ** (ydb / 10)
+    enr = 10 ** (enrdb / 10)
+    nf = 10 * math.log10(enr / (y - 1))
+    return nf
+    
+def donoisetest(r, enr):
+    print "Acquiring with noise off.."
+    setnoise(r, False)
+    off = getnoise(r)
+    print "Acquiring with noise on.."
+    setnoise(r, True)
+    on = getnoise(r)
+    return off, on, calcnf(enr, off, on)
+
+if __name__ == '__main__':
+    enr = 15.55 # From back of noise source
+    r = rsib.RSIBDevice('analyzer')
+
+    # ID instrument
+    r.write('*IDN?')
+    print "ID is " + r.read(5)
+
+    #setup(r)
+    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 "Press enter to perform a new measurement"
+        sys.stdin.readline()
+