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By defiltration, NF = (N_noise_due_to_input + N_added)/N_due_to_input
When we talk about the noise factor of a LNA under a 50 ohm system, is the input noise regarding the thermal noise of a 50 ohm source resistor? So that the output noise due to input source is K*T*B*Gain?
But let's say we...
If I want to design a good transconductor or Gm-cell for a Gm-C filter, what performance should it have?
If I want to use it to build a 2nd order LPF which cuts off at 40 MHz, what bandwidth should the Gm-cell have?
Also, people usually only talk about transconductance of the Gm-cell, but what...
In Balanis' book, the working principle of a inverted F antenna is similar with slot antenna. But why does this the radiation pattern look like a Y-direction placed magnetic dipole?
Why isn't it a X-direction placed magnetic dipole?
What makes the nulls at +Y and -Y directions?
Why is it...
When one device has multiple antennas and some of them operate in the same band (like WIFI and Bluetooth), how can we lower the coupling between two closely placed antennas? Is there any rule of thumb for antenna layout or grounding?
From the view of antenna theory, beam forming means using multiple antennas to create a desired beam, or controlling the beam direction by changing the magnitude and phase of each antenna element. Usually we'll regard all the elements as one antenna when we look at the far field.
For a typical double balanced Gilbert cell, how to match the RF input to 100 ohm?
The zero frequency input impedance should be infinity. Even when frequency increases, the input impedance doesn't change significantly at sub-6GHz range.
I understand that inductive degeneration can help...
From the equation of cascade noise figure, we can see that the noise figure of the chain is determined by the first several stages of LNA. But how to physically understand it? Why is cascade noise figure set up bu the first several stages?
in Friis equation, if the gain of transmit and receive antenna are very high, at least from this equation we may have Pr/Pt larger than 1. But since antenna is passive, it's not possible for this ratio to be larger than one. How can I understand this question? Mathematically what is...
For a low-IF receiver, how do we deal with the in-band image problem?
take this figure for example, say that it's a low-IF receiver with f_IF = 1 MHz. Thus the image for one channel could be another channel, which can't be filtered by your band-selection BPF. Then how do we solve the image...
In receiver design, we care very much about linearity and the IIP3 of the receiver must satisfy some requirements. But how is intermodulation affecting the receiver system?
I saw from the BLE 4.2 document that for bluetooth receiver, to measure the IIP3, if the desired frequency is f0, the...