Measurement instrument, measurement system, and testing method of testing a device under test
A measurement instrument for testing a DUT comprises a common port configured to be connectable to a signal output of the DUT for receiving a forward-travelling signal from the DUT. The measurement instrument further comprises a signal line connected to the common port, a signal analysis circuit and a signal generator circuit. The signal analysis circuit receives the forward-travelling signal from the common port. The signal analysis circuit is configured to analyze the forward-travelling signal in order to assess a performance of the DUT. The signal generator circuit is connected to the signal line and is configured to generate a backward-travelling signal that is forwarded to the common port. The signal generator circuit comprises a reference signal input configured to receive a reference signal from a reference signal generator. The signal generator circuit is configured to generate the backward-travelling signal based on the reference signal.
1. A measurement instrument for testing a device under test, the measurement instrument comprising:
a common port configured to be connectable to a signal output of the device under test, wherein the common port is configured to receive a forward-travelling signal from the device under test;
a signal line connected to the common port; and
a signal processing circuit, wherein the signal processing circuit comprises a signal analysis circuit and a signal generator circuit,
wherein the signal analysis circuit is connected with the common port so as to receive the forward-travelling signal from the common port,
wherein the signal analysis circuit is configured to analyze the forward-travelling signal in order to assess a performance of the device under test,
wherein the signal generator circuit is connected to the signal line, wherein the signal generator circuit is configured to generate a backward-travelling signal that is forwarded to the common port,
wherein the signal generator circuit comprises a reference signal input, the reference signal input being configured to receive a reference signal from a reference signal generator, and
wherein the signal generator circuit is configured to generate the backward-travelling signal based on the reference signal.
2. The measurement instrument of claim 1 , wherein the signal generator circuit is configured to generate the backward-travelling signal based on the reference signal such that the backward-travelling signal is forwarded to the common port in time with receiving an output signal of the device under test via the common port.
3. The measurement instrument of claim 1 , wherein the signal line comprises a first directional coupler portion, wherein the signal analysis circuit is connected with the common port via the first directional coupler portion.
4. The measurement instrument of claim 1 , further comprising a signal shaping circuit, wherein the signal shaping circuit is interconnected between the signal generator circuit and the common port.
5. The measurement instrument of claim 4 , wherein the signal shaping circuit comprises at least one of an amplifier circuit, an attenuator circuit, or a filter circuit.
6. The measurement instrument of claim 1 , wherein the signal generator circuit is configured to generate the backward-travelling signal such that the forward-travelling signal and the backward-travelling signal have a predefined amplitude relation and/or a predefined phase relation.
7. The measurement instrument of claim 1 , wherein the signal generator circuit is configured to generate the backward-travelling signal such that the forward-travelling signal and the backward-travelling signal have the same modulation type.
8. The measurement instrument of claim 1 , wherein the reference signal corresponds to an input signal of the device under test or to a signal generated by the device under test.
9. The measurement instrument of claim 1 , wherein the signal line comprises a second directional coupler portion, wherein the signal analysis circuit is connected with the signal generator circuit via the second directional coupler portion so as to receive the backward-travelling signal.
10. The measurement instrument of claim 9 , wherein the signal analysis circuit is configured to determine an impedance presented to the device under test based on the forward-travelling signal and based on the backward-travelling signal.
11. The measurement instrument of claim 9 , wherein the signal analysis circuit is configured to assess the performance of the device under test based on the forward-travelling signal and based on the backward-travelling signal.
12. The measurement instrument of claim 1 , wherein the measurement instrument is configured to operate the signal generator circuit independent of the signal analysis circuit.
13. The measurement instrument of claim 1 , wherein the backward-travelling signal corresponds to at least one of a desired load impedance, a DUT distortion, a DUT modulation, a DUT input power, or a DUT output power.
14. The measurement instrument of claim 1 , wherein the backward-travelling signal is generated based on pre-recorded measurement results obtained with a known-good device under test.
15. The measurement instrument of claim 1 , wherein the backward-travelling signal is generated based on a mathematical model of the device under test.
16. The measurement instrument of claim 1 , wherein the measurement instrument is established as a signal analyzer, a vector signal analyzer, an oscilloscope, a digital oscilloscope, or a vector network analyzer.
17. The measurement instrument of claim 1 , wherein the signal analysis circuit is configured to determine at least one of a error vector magnitude (EVM) or an adjacent channel leakage ratio (ACLR) based on the forward-travelling signal.
18. A measurement system, the measurement system comprising a measurement instrument according to claim 1 and a device under test.
19. The measurement system of claim 18 , wherein the reference signal generator is established separately from the device under test and from the measurement instrument.
20. The measurement system of claim 18 , wherein the reference signal generator is integrated into the device under test.
21. A testing method of testing a device under test by a measurement instrument, the measurement instrument comprising a common port and a signal processing circuit, wherein the common port is connectable to a signal output of the device under test, wherein the signal processing circuit comprises a signal analysis circuit and a signal generator circuit, and wherein the signal generator circuit comprises a reference signal input, the testing method comprising the steps of:
receiving, by the common port, a forward-travelling signal from the device under test;
receiving, by the reference signal input, a reference signal from a reference signal generator;
generating, by the signal generator circuit, a backward-travelling signal based on the reference signal;
forwarding the backward-travelling signal to the common port; and
analyzing, by the signal analysis circuit, the forward-travelling signal in order to assess a performance of the device under test.