Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
Dear all,
I'm choosing a 1W power amplifier for QAM 256, 20MHz bandwidth signal.
as far I know, the QAM256. 20MHz signal is such like the below.
the the total power of 20mhz signal is 1W=30dbm, the power of a 1HZ bandwidth signal is 30-10log(20*10^6)= -43dbm. besides, the PAR of 256QAM ~ 7->...
Hi all,
I'm designing a bias sequence circuit for GaN Power Amplifier, the same as "AN11130-Bias module for 50 V GaN demonstration boards".
the problem is in the off-state. the gate voltage should be goes from -5 to 0 after the drain voltage goes down to zero. It can be fine if I insert a...
Tks crutschow,
my application use low IF architecture, the IF is 170MHz. sampling frequency Fs=245.76 -> Fs/2=122.88Mhz, the image should be 75.76M. so I need bandpass filter to obtain my If signal. Did I misunderstand st ?
Hi guys, I'm using LTC5586 IQ modulator and in the datasheet, it suggest an anti-alias low pass filter with inserted-resistors, which is hard to understanding for me. I would like to ask why they do so. in this filter, if all the resistors were removed, it is normal 5th order low pass filter-...
hi guys, I wonder how TX and RX of full-duplex system work together.
As far as I know, the simple architecture likE e .So if A transmit signal f1, receive f2 then B receive f1 and transmit f2. but A and B must have the same architecture and something make them transmit and receive the reverse...
hi all, from UBX daughter board from ettus, I see that for HF & UHF (<500MHz ), they use heterodyne receiver architecture, and for microwave, they use direct conversion receiver architecture. why that ? is there any advantages of heterodyne arc for low frequency and in reverse ?? tks in advanced.
tks for your replies. yes, my ideal is exactly like what crutschow said. My design is in the receiver, so the current is not problem, let's say about under 20mA. and if I want to apply in transmitter with 3A-current, can it be possible ? 'cause due to what I searched, there's no varactor with 3A...
hi guys, I want to design a multi-voltage regulator with from 18 to 30 outputs, from 0V-15V, to control varactors. would you have any ideals for this circuit ?
supply voltage should be 15V. tks all.
thanks for your reply. "it dies" means that I have to replace the new one. the died one can't be reuse. I turn on or off the regulator outputs by shorting/opening the "NT " connection at the outputs. the schematics are followed.
- - - Updated - - -
thanks for your reply. I would try it. but my...
hi guys,
my protection circuit using LTC4368-2 have a problem. I use a triple regulater (LT8601) and when I turn on 2 in 3 outputs, then my LTC4368 die. firstly, I thought there was feedback signal somewhere but I see nothing in the osciloscope. when I turn off LT8601 outputs, everything is OK...
Re: how to choose RF amplifier ?
I would use an attenuator at the before 1st stage to control the gain. so it maybe not the problem.
there's alot amplifier with wide bw (from DC to several GHz) with high gain (upto 20). why did you suggest 5-6 stages ?
I'm going to use model D2013UK in the...
Re: how to choose RF amplifier ?
sr bro, my exactly freq is 1.5MHz to 90MHz.
like you said. the last stage almost has 10dB of gain. but the 1st and 2nd maybe 18 to 20 dB of gain. but I want some gain margin. which is enough ? if it's pretty high, it seems like that I have to do with 4 stages...
how to choose RF amplifier ?
I'm designing a 5W (37dBm) HF PA with -10dbm input power.
the PA should have 2 or 3 stages ? and how can I choose the right PA ? I mean which parameters of PA at each stage should I care to choose the right one ?
tks a lot.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
