Differences between in-band and out-of-band gain compression

[milvapp]

Hello,

I would like to know the main-substantial differences between in-band and out-of-band
1dB compression point.(Apart from the obvious difference of the working frequency,
I would like to know the effects of it-what saturates first and so on)

If there is any known material you can provide please let me know.

Thanks.

 

[jiripolivka]

The in-band gain compression is a measure of device linearity, and cannot be improved but by setting a higher device current. The gain compression due to an out-of-band signal is the result of interference, and it can be improved by filtering. A suitable filter should reject the out-of-band interfering signals so they would not affect the desired signal.

 

[milvapp]

Hi jiripolivka.thank you for your reply.

So if I understood correctly,in-band compression is a measurement that is not affected by the interferer,while the out-of-band is?
Regarding the in-band compression,by increasing the current consumption this increases the voltage drop at the load resistors
so inj that way linearity gets better?Can you clarify that a bit more?

Thank you in advance.

 

[jiripolivka]

Hi jiripolivka.thank you for your reply.

So if I understood correctly,in-band compression is a measurement that is not affected by the interferer,while the out-of-band is?
Regarding the in-band compression,by increasing the current consumption this increases the voltage drop at the load resistors
so inj that way linearity gets better?Can you clarify that a bit more?

Thank you in advance.

The in-band compression is the device specification. The out-of-band compression is system-related as I explained.
In typical amplifiers and MMICs, linearity is proportional to device current. Resistors are needed to establish its operation point.