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As we know, the input of VCO is control voltage, which generates output frequency.
The PLL block diagram is as below:
So, here comes one question:
What is the input of VCO in a PLL architecture? As that red circle
(1). Oscillating frequency?
(2). Control voltage?
If it is...
As shown above, the reference sensitivity requirement:
B1: -106.7
B2: -104.7
B3: -103.7
B4: -106.7
B5: -104.7
They are different.
However, from the sensitivity formula,
These parameters, such as bandwidth, SNRmin, are all the same in these bands.
In theory, the reference sensitivity...
Sorry, perhaps my previous photo didn't expound my question well.
The two photos are from datasheet.
As shown above, C1 is just the shunt component, and which is always implemented as an inductor.
Other datasheets almost adopt the identical design.
I'm wondering that why is the...
Hi,
As shown above,
there is always a shunt inductor in SMD (Surface Mount Device) antenna design.
I know it's for tuning.
Nevertheless, why is inductor always used here?
Capacitor is rarely seen here.
What key words should I google to understand the detailed explanation?
Thanks a lot~!!
Hi,
For the description:
Due to the differences between
FDD and TDD, the same amount of aggregated bandwidth results in different downlink and uplink data rates.
Therefore, 40-MHz aggregated bandwidth in FDD-LTE results in a maximum downlink data rate of 300 Mb/s,
while 40 MHz aggregated in...
HI,
As shown above, there is carrier leakage caused by a DC offset in I/Q signal.
And, in terms of spectrum, the carrier leakage component is at the center of signal.
Nevertheless,
As shown above, in terms of spectrum, the carrier leakage component is between image and...
Hi,
Of course, the better the linearity of PA is, the better the TX performance will be.
Nevertheless, GSM adopts GMSK modulation, which is constant envelope.
In other words, it doesn't need back-off to maintain linearity.
It can even operate in saturation mode.
But, I'm confused.
Now...
Hi,
Thanks for your reply. My thought is as below:
1. According to Friis formula :
For the total noise figure of RX path,
the individual noise figure of these stages posterior to LNA can be ignored because they have gain in their denominator.
For example :
The RX path has 4...
BGA231L7 of Infineon
ALM-2412 of AVAGO
As shown above, obviously, the series inductor at LNA input is Input Matching to achieve minimum noise figure, thereby improving sensitivity.
Nevertheless, the inductor value is 6.8nH and has 1.8dB insertion loss@ GPS frequency...
Hi,
We all know that more complex modulation leads to higher data rate and PAPR.
For example,
256 QAM has higher data rate and PAPR than 64 QAM.
But, why ?
Would you please tell me which keywords should I google ?
Thanks a lot~!
But I wonder why IM2 appears at LNA input.
IM2 made up of Tx and RX is due to LNA's and mixer's nonlinearity.
(I leave blocker/jammer considerations aside)
In that case, why does IM2 appear at LNA input ?
Besides, if we put a DC-block at LNA input,
the IM2 near baseband frequency will NOT...
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