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Dear,

I was find revision datatsheet from A to B.   I need to update RX Gain budget in my system path. I wonder if there is a  between how to measure the three Gain items. (6 page)

Also, I read remark on the datasheet, but I didn't understand it.

Especially, how do you check Rx Gain budget for number 3?

1. Maximum single channel gain 7dB  (ex. Rxin0 Input :0 dB,   Rxin1,2,3 : Termination,  RF_IO output : 7dB)

2. Maximum Electronic gain 13dB    (ex. Rxin0 Input :0 dB,   Rxin1,2,3 : open,  RF_IO output : 13dB)

3. Maximum Coherent gain 19dB     (ex. Rxin0, 1, 2, 3 Input :0 dB,  RF_IO output :19dB)

Best & Regards,

Parents
• Single Channel and Coherent Gains are correct.  Electronic Gain as stated is not correct.

You can define Electronic gain as the output power/sum of the input powers.   So it is basically measured the same way as coherent gain, but instead of being referenced to a single inputs' power, it is the sum of the input powers.   So if you have 0 dBm (1 mW) on each input, across four inputs, that is 4 mW sum.  If the output is at 19 dBm (79.5 mW), then the electronic gain is:

• 10*log10(79.5 / 4) = 13 dB

Coherent gain would be:

• 10*log10(79.5 / 1) = 19 dB

I am assuming the signals are the same amplitude when applied to the combiner and in-phase with each other.

By the way, these input powers would push the receive well into its compression, so they are not realistic.  The above analysis assumes that the compression isn't happening.

• Single Channel and Coherent Gains are correct.  Electronic Gain as stated is not correct.

You can define Electronic gain as the output power/sum of the input powers.   So it is basically measured the same way as coherent gain, but instead of being referenced to a single inputs' power, it is the sum of the input powers.   So if you have 0 dBm (1 mW) on each input, across four inputs, that is 4 mW sum.  If the output is at 19 dBm (79.5 mW), then the electronic gain is:

• 10*log10(79.5 / 4) = 13 dB

Coherent gain would be:

• 10*log10(79.5 / 1) = 19 dB

I am assuming the signals are the same amplitude when applied to the combiner and in-phase with each other.

By the way, these input powers would push the receive well into its compression, so they are not realistic.  The above analysis assumes that the compression isn't happening.

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