Forums › BB Series Discussions › BB66C Input Impedance
- This topic has 2 replies, 3 voices, and was last updated 7 years, 8 months ago by Bruce.
Roger PetersonParticipantRoger Peterson February 25, 2015 at 9:05 am
According to specifications, the BB66C should have an input impedance of 50 ohms.
Using a 50 ohm output signal generator (Agilent 33220A), an output frequency of 10KHz is selected with an output level of -20dBm.
The signal generator is TEED with an oscilloscope (high input Z) and the BB66C.
If the BB66C has an input Z of 50 ohms, the scope should read a -20dB level, but it does not.
Using just an ohmmeter, the input R of the BB66C is >1M ohm with or without power.
Using the same above test procedures with the USB-SA44B, all is normal (as expected).
I just want to verify that the BB66C does or does not have an input Z of 50 ohms?
AndrewModeratorAndrew February 25, 2015 at 11:50 am
Thank you for calling in. Hopefully we were able to fully answer your questions. If you need anything further please let us know.
BruceModeratorBruce July 23, 2015 at 6:31 pm
For anyone else that is curious, The BB60C has a 50Ω input impedance and AC input coupling so it won’t look like 50Ω using a multimeter but at RF frequencies it is 50Ω. The SA44B has a DC coupled input so it will look like 50Ω to a multimeter.
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