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Added calibration test with actual measurements

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This commit is contained in:
Jan Käberich 2022-11-17 18:06:18 +01:00
parent 2b9cc78e55
commit 94fc6ab840
4 changed files with 117823 additions and 6 deletions
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90
Software/Integrationtests/tests/TestCalibration.py
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@ -1,13 +1,15 @@
from tests.TestBase import TestBase
from libreCAL import libreCAL
import time
import math
class TestCalibration(TestBase):
def cal_measure(self, number):
def cal_measure(self, number, timeout = 3):
self.vna.cmd(":VNA:CAL:MEAS "+str(number))
# wait for the measurement to finish
timeout = time.time() + 3
stoptime = time.time() + timeout
while self.vna.query(":VNA:CAL:BUSY?") == "TRUE":
if time.time() > timeout:
if time.time() > stoptime:
raise AssertionError("Calibration measurement timed out")
time.sleep(0.1)
@ -80,3 +82,85 @@ class TestCalibration(TestBase):
self.assertEqual(self.vna.query(":VNA:CAL:ACT SOLT_1"), "")
self.assertEqual(self.vna.query(":VNA:CAL:ACT SOLT_2"), "")
self.assertEqual(self.vna.query(":VNA:CAL:ACT SOLT_12"), "")
def assertTrace_dB(self, trace, dB_nominal, dB_deviation):
for S in trace:
dB = 20*math.log10(abs(S[1]))
self.assertLessEqual(dB, dB_nominal + dB_deviation)
self.assertGreaterEqual(dB, dB_nominal - dB_deviation)
def test_SOLT_calibration(self):
# This test performs a 2-port SOLT calibration with a connected LibreCAL
# Afterwqrds, the calibration is checked with a 6dB attenuator
# Set up the sweep first
self.vna.cmd(":DEV:MODE VNA")
self.vna.cmd(":VNA:SWEEP FREQUENCY")
self.vna.cmd(":VNA:STIM:LVL -10")
self.vna.cmd(":VNA:ACQ:IFBW 1000")
self.vna.cmd(":VNA:ACQ:AVG 1")
self.vna.cmd(":VNA:ACQ:POINTS 501")
self.vna.cmd(":VNA:FREQuency:START 50000000")
self.vna.cmd(":VNA:FREQuency:STOP 6000000000")
self.vna.cmd(":VNA:CAL:RESET")
# Load calibration file (only for standard and measurement setup, no
# measurements are included)
self.assertEqual(self.vna.query(":VNA:CAL:LOAD? LIBRECAL.CAL"), "TRUE")
# Take the measurements
cal = libreCAL()
# Connections:
# LibreVNA -> LibreCAL
# 1 -> 3
# 2 -> 1
cal.reset()
cal.setPort(cal.Standard.OPEN, 1)
cal.setPort(cal.Standard.OPEN, 3)
self.cal_measure(0, 15)
self.cal_measure(3, 15)
cal.setPort(cal.Standard.SHORT, 1)
cal.setPort(cal.Standard.SHORT, 3)
self.cal_measure(1, 15)
self.cal_measure(4, 15)
cal.setPort(cal.Standard.LOAD, 1)
cal.setPort(cal.Standard.LOAD, 3)
self.cal_measure(2, 15)
self.cal_measure(5, 15)
cal.setPort(cal.Standard.THROUGH, 1, 3)
self.cal_measure(6, 15)
# activate calibration
self.assertEqual(self.vna.query(":VNA:CAL:ACT SOLT_12"), "")
# switch in 6dB attenuator
cal.setPort(cal.Standard.THROUGH, 1, 2)
cal.setPort(cal.Standard.THROUGH, 3, 4)
# Start measurement and grab data
self.vna.cmd(":VNA:ACQ:SINGLE TRUE")
while self.vna.query(":VNA:ACQ:FIN?") == "FALSE":
time.sleep(0.1)
cal.reset()
# grab trace data
S11 = self.vna.parse_trace_data(self.vna.query(":VNA:TRACE:DATA? S11"))
S12 = self.vna.parse_trace_data(self.vna.query(":VNA:TRACE:DATA? S12"))
S21 = self.vna.parse_trace_data(self.vna.query(":VNA:TRACE:DATA? S21"))
S22 = self.vna.parse_trace_data(self.vna.query(":VNA:TRACE:DATA? S22"))
# Attenuation is frequency dependent, use excessively large limits
# TODO: use smaller limits based on frequency
self.assertTrace_dB(S12, -13, 5)
self.assertTrace_dB(S21, -13, 5)
# Reflection should be below -10dB (much lower for most frequencies)
self.assertTrace_dB(S11, -100, 90)
self.assertTrace_dB(S22, -100, 90)