Hi,
What is the correct way to measure the output power of a WLAN signal source using the TkPower?
For example, if I directly attach the TkPower to the RF output of the WLAN_80211a_RF (802.11a source with RF modulation), taking care that the output resistance of the source and the reference resistance of the meter are matched, shouldn't that yield the correct result?
My observations-
1. If I take the WLAN_80211a_RF, keep all default paramters, and for a fixed modulator output power, say dbmtow(15), I change the order, the output power measured by the meter changes (with large aberrance > 6 dBm per increase of 1 in the order).
2. Similarly the measured power for many other modulators like 802.11b source, is not the same is set.
Where am I going wrong in using/understanding the TkPower meter?
Thanks in advance.
What is the correct way to measure the output power of a WLAN signal source using the TkPower?
For example, if I directly attach the TkPower to the RF output of the WLAN_80211a_RF (802.11a source with RF modulation), taking care that the output resistance of the source and the reference resistance of the meter are matched, shouldn't that yield the correct result?
My observations-
1. If I take the WLAN_80211a_RF, keep all default paramters, and for a fixed modulator output power, say dbmtow(15), I change the order, the output power measured by the meter changes (with large aberrance > 6 dBm per increase of 1 in the order).
2. Similarly the measured power for many other modulators like 802.11b source, is not the same is set.
Where am I going wrong in using/understanding the TkPower meter?
Thanks in advance.
So if you just connect the WLAN_80211a_RF source to a TkPower component and use RefR to 50 Ohm you are not actually measuring the right power because the ouptut of the source is not matched. So first connect a 50 Ohm load resistor to the output of the source.
Now the default values of the source should give the correct power reading in the TkPower. If you change some parameters you need to calibrate the source by setting the VRef parameter correctly.
Push into the source, activate TkIQrms and TkPower components, go back to your top level design and run a simulation. Observe the "input IQ signal rms value" in the Agilent Ptolemy Control Panel window until it settles down to a stable value (if you have an long Idle part the value might fluctuate quite a bit). Quit the simulation and set the VRef parameter of the source to the input IQ signal rms value you observed. Finally, push into te source again and deactivate TkIQrms and TkPower components (leaving them activated can slow down your simulation significantly).
Kostas.