AWR1243: What's different between RX Gain and RF Gain Target?

Wesley He

Expert 6225 points

Part Number: AWR1243

Hi team,

I have a customer asking about the correct gain value using in AFE.

As we known, The RX gain is the gain of the complete RX chain, including LNA, VGA.

For example, If we get 0dBm at before ADC. And the Rx Gain is set to 30dB, RF Gain Target is set to 26dB.

Does it means the signal input from RX pin is 0-30-26 = -56dBm?

Is the RF Gain Target means the 77GHz LNA Gain before 77GHz Mixer?

Thanks,

Regards,

Wesley

over 7 years ago

0 Vivek Dham over 7 years ago

TI__Guru 58035 points

Hello Wesley,
The RX analog chain has two main components, one if the RF (ie the LNS , mixer), and second the baseband after down convertion(ie the VGA, HPF etc.). The RX chain corresponds to the complete RX chain gain, RF + baseband. The RF gain is the LNA and mixer only.
The firmware tries to achieve the RF target gain and the remaining gain is got from the baseband to meet the Rx chain gain.

Regards,
vivek

0 Wesley He over 7 years ago in reply to Vivek Dham

TI__Expert 6225 points

Hi Vivek,
Thanks for your reply.
Let's assume that Gain Target is 30dB, Rx Gain is 40dB.
Does it means device try to achieve 30dB Gain in RF side . But in fact, it might be less than 30dB, for example 25dB. Then actual gain in baseband side will be 15dB, to meet the Rx gain requirement 40dB. Is that right?

Regards,
Wesley

0 Vivek Dham over 7 years ago in reply to Wesley He

TI__Guru 58035 points

Hello Wesley,
That is right.

Regards,
Vivek

0 rongjiang liu over 7 years ago in reply to Wesley He

Expert 1275 points

thanks
good reply

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AWR1243: What's different between RX Gain and RF Gain Target?