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Re: spur!!!amplifier when input 192MHz bandwidth QAM256 sign
Thanks biff44
The spur 2 and 3 is coming from clock, which is 512MHz.
Those spur form 40MHz to 120MHz may be produced by 2 order nonlinearity. But the output power is far away less than P1dB of ACA2407. The P1dB may be 24dBm.
When...
When input 192MHz bandwidth QAM256 signal, there is some spur frmo 40MHz to 120MHz. The input signal frequency is 189~381MHz,32channel, power level is -39dBm per channel. The amplifier is ACA2407. Why?
Thanks!
50~860MHz VGA??
Which part of variable gain amplifier can be used in this field?
spec:
frequency band: 50~860MHz
impedance: 75 Ohm
OIP3: 38dBm
gain maximum:at least 15dB
gain adjust range: 20dB
Thanks
regulator noise
How to estimate the effect of regulator noise?
For example a CATV outdoor amplifier. The signal is 256QAM, the amplifier part is hybrid amplifier module, the regulator in the amplifier is LM7824. LM7824 noise 100Hz to 100KHz is 10uV/Vo.
Whether the regulator LM7824 is good...
Re: PLL problem??
Thanks
I changed the frequency setting in simulation, and get a new loop filter values.
When the loop bandwidth is increased a bit, the loop is stable.
Re: PLL problem??
I calculated the loop filter values using Analog Device PLLsim3.0 loop bandwidth is 800Hz, phase margin is 43 degree. Perhaps the phase margin simulation is not same as measurement.
troubleshooting pll problems
Test condition
PLL chip :adf4106
VCO :950MHz~2150MHz
charge pump current:2.5mA
loop bandwidth: 800Hz
PHD frequency(reference frequency):3MHz
loop type type A
test result
I want to konw the probably cause.
Thanks
active loop filter
I wonder how to build a active loop filter in pll circuit. the CP pin of PLL chip connecte with "+" of OP. Why??
Added after 5 hours 18 minutes:
please see the image
The image is from internet. So I don't get high quality image.
The function of the inductor is get 60V 60Hz AC current from coaxial cable, the signal frequency is 5~860MHz. In the schematic, it is a broadband(5~860MHz)chock
Thanks.
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