Calculating the RF composite power from different signals
时间：04-08
整理：3721RD
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Hi All,
I am wondering how to calculate the composite power (total power) that hits an LNA input of a receiver chain when working with two input signals of different technologies in order to see if this will impact on the P1dB of the LNA.
One signal is a WCMDA of 3.84 MHz with -20 dBm of power. It is worth to say that WCDMA has a PAR = 10.5 dB, so apparently it sounds I have to add 10.5 dB on the top of -20 dBm if I want to let's say normalize it to work with P1dB and see if it is saturating.
The other signal is a GSM TDMA of 200 KHz with -10 dBm of power, but it uses time slot technology which is not transmitting all the time. I guess here if we know the time slot duration and it's gap then we can derive the duty cycle and calculate this 'average" power.
Again, important is to know how to quantify these two signals and compare it with P1dB spec of the LNA and see if it is saturating or not.
Any comments are welcome. Tks.
I am wondering how to calculate the composite power (total power) that hits an LNA input of a receiver chain when working with two input signals of different technologies in order to see if this will impact on the P1dB of the LNA.
One signal is a WCMDA of 3.84 MHz with -20 dBm of power. It is worth to say that WCDMA has a PAR = 10.5 dB, so apparently it sounds I have to add 10.5 dB on the top of -20 dBm if I want to let's say normalize it to work with P1dB and see if it is saturating.
The other signal is a GSM TDMA of 200 KHz with -10 dBm of power, but it uses time slot technology which is not transmitting all the time. I guess here if we know the time slot duration and it's gap then we can derive the duty cycle and calculate this 'average" power.
Again, important is to know how to quantify these two signals and compare it with P1dB spec of the LNA and see if it is saturating or not.
Any comments are welcome. Tks.
averaging calculation method should not be applied. You will looses the PAR and fall in non linearity / harmonics
calculate based on "instant of time".