BB66C Input Impedance

[Roger Peterson]

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?

[Andrew]

Hello Roger,

Thank you for calling in. Hopefully we were able to fully answer your questions. If you need anything further please let us know.

Regards,
A.J.

[Bruce]

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.

Bruce

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