Hello everyone,
During a RF measurement I noticed that my output power when the signal is modulated is higher than when it is not.
My setup for this test is as following :
My RF generator (RIGOL DSG815) is connected to my spectrum analyzer (R&S FPC1000). My modulating signal is coming from a function generator (plugged on the "EXT MOD IN" input of my HF generator).
Setting for my RF generator :
-Center frequency = 433,42MHz
-Level : -50dBm
-Modulation : AM
-Depth : 100%
-Coupling (AC)
-Input impedance of the external modulating input (100kOhm)
Setting for my RF analyzer :
-Center frequency =433,42MHz
-Span = 10MHz
-RBW = 500kHz
-I did my power measure by setting the analyzer into "Max hold" mode
Setting for my function generator :
-Square wave
-1Khz
-Duty 50%
-1Vpp (+-500mV) -> (I read on the RF generator manual that it is the recommended amplitude for this signal)
What I see during my measurements :
-When my output is not modulated, I measure my -50dBm as expected).
-With the modulating signal is activated, I measure an output power at -44dBm (My expectation is to have a power of -50dBm too).
Are my expectations wrong ? Or is it my setup that is not correct ?
I am annoyed for my measurements because the finality is to measure the RF sensitivity of my product, so I am afraid to perform a bad measure !
Thanks for your help guys !
During a RF measurement I noticed that my output power when the signal is modulated is higher than when it is not.
My setup for this test is as following :
My RF generator (RIGOL DSG815) is connected to my spectrum analyzer (R&S FPC1000). My modulating signal is coming from a function generator (plugged on the "EXT MOD IN" input of my HF generator).
Setting for my RF generator :
-Center frequency = 433,42MHz
-Level : -50dBm
-Modulation : AM
-Depth : 100%
-Coupling (AC)
-Input impedance of the external modulating input (100kOhm)
Setting for my RF analyzer :
-Center frequency =433,42MHz
-Span = 10MHz
-RBW = 500kHz
-I did my power measure by setting the analyzer into "Max hold" mode
Setting for my function generator :
-Square wave
-1Khz
-Duty 50%
-1Vpp (+-500mV) -> (I read on the RF generator manual that it is the recommended amplitude for this signal)
What I see during my measurements :
-When my output is not modulated, I measure my -50dBm as expected).
-With the modulating signal is activated, I measure an output power at -44dBm (My expectation is to have a power of -50dBm too).
Are my expectations wrong ? Or is it my setup that is not correct ?
I am annoyed for my measurements because the finality is to measure the RF sensitivity of my product, so I am afraid to perform a bad measure !
Thanks for your help guys !