mirror of
https://github.com/jankae/LibreVNA.git
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95e59769fd
libraVNA.cmd() no longer expects blank line responses. By default, it checks status after each command to match the previous behavior. Check can be disabled by optional cmd() parameter for handling expected failure cases. Commands such as *WAI may take longer than anything previously. Make it possible to override the default time-out in cmd() and query(). Change poll loops in TestCalibration and TestVNASweep to *WAI calls.
176 lines
6.6 KiB
Python
176 lines
6.6 KiB
Python
from tests.TestBase import TestBase
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from libreCAL import libreCAL
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import time
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import math
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class TestCalibration(TestBase):
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def cal_measure(self, number, timeout = 3):
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self.vna.cmd(":VNA:CAL:MEAS "+str(number))
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# wait for the measurement to finish
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assert self.vna.query(":VNA:CAL:BUSY?") == "TRUE"
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self.vna.cmd("*WAI")
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assert self.vna.query(":VNA:CAL:BUSY?") == "FALSE"
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def test_dummy_calibration(self):
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# This test just iterates through the calibration steps. As no actual standards
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# are applied to the ports, the calibration result is just random data
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# Set up the sweep first
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self.vna.cmd(":DEV:MODE VNA")
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self.vna.cmd(":VNA:SWEEP FREQUENCY")
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self.vna.cmd(":VNA:STIM:LVL -10")
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self.vna.cmd(":VNA:ACQ:IFBW 50000")
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self.vna.cmd(":VNA:ACQ:AVG 1")
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self.vna.cmd(":VNA:ACQ:POINTS 501")
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self.vna.cmd(":VNA:FREQuency:START 1000000")
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self.vna.cmd(":VNA:FREQuency:STOP 6000000000")
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self.vna.cmd(":VNA:CAL:RESET")
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# No measurements yet, activating should fail
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self.vna.cmd(":VNA:CAL:ACT SOLT_1", check=False)
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self.assertTrue(self.vna.get_status() & 0x3C)
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# Load calibration kit
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self.assertEqual(self.vna.query(":VNA:CAL:KIT:LOAD? DUMMY.CALKIT"), "TRUE")
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# Lets take the measurements for port 1 first
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self.vna.cmd(":VNA:CAL:ADD OPEN")
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self.vna.cmd(":VNA:CAL:ADD SHORT")
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self.vna.cmd(":VNA:CAL:ADD LOAD")
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self.vna.cmd(":VNA:CAL:PORT 0 1")
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self.vna.cmd(":VNA:CAL:PORT 1 1")
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self.vna.cmd(":VNA:CAL:PORT 2 1")
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self.cal_measure(0)
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self.cal_measure(1)
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self.cal_measure(2)
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# SOLT_1 should now be available
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self.vna.cmd(":VNA:CAL:ACT SOLT_1", check=False)
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self.assertFalse(self.vna.get_status() & 0x3C)
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# SOLT_2 and SOLT_12 should still be unavailable
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self.vna.cmd(":VNA:CAL:ACT SOLT_2", check=False)
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self.assertTrue(self.vna.get_status() & 0x3C)
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self.vna.cmd(":VNA:CAL:ACT SOLT_12", check=False)
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self.assertTrue(self.vna.get_status() & 0x3C)
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# Take measurements for SOLT_2
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self.vna.cmd(":VNA:CAL:ADD OPEN")
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self.vna.cmd(":VNA:CAL:ADD SHORT")
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self.vna.cmd(":VNA:CAL:ADD LOAD")
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self.vna.cmd(":VNA:CAL:PORT 3 2")
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self.vna.cmd(":VNA:CAL:PORT 4 2")
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self.vna.cmd(":VNA:CAL:PORT 5 2")
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self.cal_measure(3)
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self.cal_measure(4)
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self.cal_measure(5)
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# SOLT_1 and SOLT_2 should now be available
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self.vna.cmd(":VNA:CAL:ACT SOLT_1", check=False)
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self.assertFalse(self.vna.get_status() & 0x3C)
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self.vna.cmd(":VNA:CAL:ACT SOLT_2", check=False)
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self.assertFalse(self.vna.get_status() & 0x3C)
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# SOLT_12 should still be unavailable
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self.vna.cmd(":VNA:CAL:ACT SOLT_12", check=False)
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self.assertTrue(self.vna.get_status() & 0x3C)
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# Take the final through measurement for SOLT_12
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self.vna.cmd(":VNA:CAL:ADD THROUGH")
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self.vna.cmd(":VNA:CAL:PORT 6 1 2")
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self.cal_measure(6)
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# SOLT_1, SOLT_2 and SOLT_12 should now be available
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self.vna.cmd(":VNA:CAL:ACT SOLT_1", check=False)
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self.assertFalse(self.vna.get_status() & 0x3C)
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self.vna.cmd(":VNA:CAL:ACT SOLT_2", check=False)
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self.assertFalse(self.vna.get_status() & 0x3C)
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self.vna.cmd(":VNA:CAL:ACT SOLT_12", check=False)
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self.assertFalse(self.vna.get_status() & 0x3C)
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def assertTrace_dB(self, trace, dB_nominal, dB_deviation):
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for S in trace:
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dB = 20*math.log10(abs(S[1]))
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self.assertLessEqual(dB, dB_nominal + dB_deviation)
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self.assertGreaterEqual(dB, dB_nominal - dB_deviation)
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def test_SOLT_calibration(self):
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# This test performs a 2-port SOLT calibration with a connected LibreCAL
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# Afterwqrds, the calibration is checked with a 6dB attenuator
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# Set up the sweep first
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self.vna.cmd(":DEV:MODE VNA")
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self.vna.cmd(":VNA:SWEEP FREQUENCY")
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self.vna.cmd(":VNA:STIM:LVL -10")
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self.vna.cmd(":VNA:ACQ:IFBW 1000")
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self.vna.cmd(":VNA:ACQ:AVG 1")
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self.vna.cmd(":VNA:ACQ:POINTS 501")
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self.vna.cmd(":VNA:FREQuency:START 50000000")
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self.vna.cmd(":VNA:FREQuency:STOP 6000000000")
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self.vna.cmd(":VNA:CAL:RESET")
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# Load calibration file (only for standard and measurement setup, no
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# measurements are included)
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self.assertEqual(self.vna.query(":VNA:CAL:LOAD? LIBRECAL.CAL"), "TRUE")
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# Take the measurements
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cal = libreCAL()
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# Connections:
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# LibreVNA -> LibreCAL
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# 1 -> 3
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# 2 -> 1
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cal.reset()
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cal.setPort(cal.Standard.OPEN, 1)
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cal.setPort(cal.Standard.OPEN, 3)
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self.cal_measure(0, 15)
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self.cal_measure(3, 15)
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cal.setPort(cal.Standard.SHORT, 1)
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cal.setPort(cal.Standard.SHORT, 3)
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self.cal_measure(1, 15)
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self.cal_measure(4, 15)
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cal.setPort(cal.Standard.LOAD, 1)
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cal.setPort(cal.Standard.LOAD, 3)
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self.cal_measure(2, 15)
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self.cal_measure(5, 15)
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cal.setPort(cal.Standard.THROUGH, 1, 3)
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self.cal_measure(6, 15)
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# activate calibration
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self.vna.cmd(":VNA:CAL:ACT SOLT_12", check=False)
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self.assertFalse(self.vna.get_status() & 0x3C)
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# switch in 6dB attenuator
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cal.setPort(cal.Standard.THROUGH, 1, 2)
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cal.setPort(cal.Standard.THROUGH, 3, 4)
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# Start measurement and grab data
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self.vna.cmd(":VNA:ACQ:SINGLE TRUE")
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self.assertEqual(self.vna.query(":VNA:ACQ:FIN?") == "FALSE")
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self.vna.cmd("*WAI")
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self.assertEqual(self.vna.query(":VNA:ACQ:FIN?") == "TRUE")
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cal.reset()
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# grab trace data
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S11 = self.vna.parse_VNA_trace_data(self.vna.query(":VNA:TRACE:DATA? S11"))
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S12 = self.vna.parse_VNA_trace_data(self.vna.query(":VNA:TRACE:DATA? S12"))
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S21 = self.vna.parse_VNA_trace_data(self.vna.query(":VNA:TRACE:DATA? S21"))
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S22 = self.vna.parse_VNA_trace_data(self.vna.query(":VNA:TRACE:DATA? S22"))
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# Attenuation is frequency dependent, use excessively large limits
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# TODO: use smaller limits based on frequency
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self.assertTrace_dB(S12, -13, 5)
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self.assertTrace_dB(S21, -13, 5)
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# Reflection should be below -10dB (much lower for most frequencies)
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self.assertTrace_dB(S11, -100, 90)
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self.assertTrace_dB(S22, -100, 90)
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