Spectrum Analyzer
Notes
spectrum analyzer input <> DC Block <> SMA to BNC <> DUT
spectrum analyzer input <> DC Block <> DUT
Connect TX to Spectrum Analyzer
TX <in[directional coupler]out><in[dummy load xxW]testing port> <10db attenuator> spectrum analyzer
__________
|
|
- ?
Max Power: take max input of spectrum analyzer, let's say +20dBm
You can calculate the max power in dBm:
100W = 50dBm
30W = 44dBm
\[ dBm = 10\times\log_{10}\left(\frac{30W}{0.001W (1mW)}\right) = 44.77dBm \]
Since they are too high related to the +20dBm max input, you can put the required attenuators to get down to 0dBm.
- 50dBm = -40dB + -10dB, or -50dB
- 44dBm = -40dB + 4dB
TX 50dBm <> dummy load -40dB <> -10dB <> 0dBm spectrum analyzer
Max Voltage, let's say, maximum 5V in:
30W in volts formula: \[ V = \sqrt{30W \times 50\Omega} = 38.7V \]
The equivalent dBm for the 5V max input of the instrument: \[ dBm = 20\times\log_{10}\left(\frac{5V}{0.224V (224mV = 0dBm)}\right) = 26.9dBm \]
Using 27dB attenuation will do the job.
Refs
- LPC501 Directional Coupler
- Dummy Load with "testing port"/tap/monitor (-40dB)
- See references for attenuators, directional couplers, etc.
- dBm units