124 Threads found on edaboard.com: Fm Using Vco
Hi all,
I want to implement a simple communication system with digital FM using vco, but Igot confused about using vco for modulation in matlab!
Also, after modulation there are limiter and discriminator blocks, is it necessary to use demodulation matlab function in this system?
Finally, for this simple system, can I use (...)
Digital communication :: 22.06.2012 10:55 :: sanam86 :: Replies: 0 :: Views: 202
vco : voltage controlled oscillator
is a kind of oscillator, that is enable to change its frequency
due to some external voltage applied across it.
A probably most important component is a varactor diode.
You can refer a book about varactor diode. If you apply
a varying voltage across it, the capacitance of the diode
will change in it r
RF, Microwave, Antennas and Optics :: 30.07.2005 08:42 :: mudrik :: Replies: 2 :: Views: 781
Hey u cannot do frequency modulation with pll.. U can only demodulate fm with plll... So better try using vco or any other method to modulate and use pll to demodulate..
Sure you can if you pick your loop BW right
Hobby Circuits and Small Projects Problems :: 19.06.2006 07:00 :: E-design :: Replies: 6 :: Views: 3596
i'd like to ask something. Is this vco very stable??? mean quick stable time from the on time of the power supply and after a long time (eg. 6hours or more)
i've playing with FM TX for some years using vco with ordinary HF transistor and it not so stable :|:|
considering using pll, but it
Microcontrollers :: 11.09.2006 14:22 :: ex4 :: Replies: 0 :: Views: 540
Lately I noticed that there's a new interesting product from National, the LMX2541, the first pll/vco combo chip I know of that has a frequency range that covers 6m, 2m and 70cm and is therefore also interesting for ham homebrewing.
However I'm uncertain about how such a combo chip is fm-modulated, I would prefer direct (true) fm. Normally the v
RF, Microwave, Antennas and Optics :: 03.01.2011 23:19 :: atlantis7 :: Replies: 23 :: Views: 1613
You are going to have a hard time making a PLL without using a PLL "chip"!
If you could use a PLL chip, you would choose one with an onboard charge pump. Then you could set up a passive loop filter with a narrow loop bandwidth (perhaps 2 KHz bandwidth) and connect that to the vco tuning port. Then you could also AC couple a modulating signal o
Analog Circuit Design :: 05.06.2011 04:34 :: biff44 :: Replies: 18 :: Views: 1785
Yingyang, You need a huge fractional bandwidth.
You can modulate narrow-band FM and then apply multiply-and shift method: frequency multiplying multiplies the frequency deviation, and down-conversion conserves it, increasing the fractional deviation.
Regards
Z
RF, Microwave, Antennas and Optics :: 13.01.2003 15:37 :: zorro :: Replies: 16 :: Views: 5103
Hey!
I'm designing a system in FM, in 1.000 Mhz to 2.000 Mhz (yes Mhz 1000Khz), to modulate audio.
In first time, i used the vco of a CD4046, so I connect a potentiomenter to it in a way to set the frecuency like this:
+-------+......VCC
|...CD...|....... \
|..4046..|---->/--------| |------ Audio in
|...........|...... \
+-------
Professional Hardware and Electronics Design :: 28.06.2002 19:03 :: penrico :: Replies: 3 :: Views: 1062
Hello:
I have build a FM radio using STR TEA5757, according Philips Application note AN99041.
I have a problem with FM vco alignment. If you align vco coil the tunning voltage should change between 0.8V(88MHz) and 1.9V(108MHz), but in my PCB this isn't happen.
If I align my vco coil the tunning voltage is constant in (...)
RF, Microwave, Antennas and Optics :: 12.09.2002 10:40 :: tipet20002000 :: Replies: 10 :: Views: 5919
one further question
all these oscilator designs tap power from the emiter { this is daft }
better to couple the signal from the collector via a small 3.3R load res and a 10 pf cap
very little coupled and amplify lots on the next stage
= a very stable oscilator
the key is stablility not componet count
RF, Microwave, Antennas and Optics :: 04.03.2003 04:38 :: sick_man :: Replies: 15 :: Views: 2251
you are all wrong
TV signals are a transition of k3F mode or phastidual sideband
not therefore AM
and only a form of modualted sideband so it a far different mode
it is ment for soaking a wide area while not suffering too much from relections and diverse interferance's
however if it was am the carrie
RF, Microwave, Antennas and Optics :: 08.09.2003 17:50 :: sick_man :: Replies: 17 :: Views: 5913
how to modulate fm digitally?
thanks in advance.
Digital Signal Processing :: 03.01.2004 09:46 :: jsp :: Replies: 6 :: Views: 1858
Greetings...
When you desing a vco, you must maintain a tradeoff between quality factor and wideband. Basically, noise phase affects your design as well as noise signals modulate the bias point in varactor, resulting in a FM signal.
Both ring oscillator and tank LC are the most discussed topologies about vco. However, first one can tunnig in a
Analog Circuit Design :: 22.05.2004 06:37 :: mazelk :: Replies: 19 :: Views: 7152
Reduce your input switching freq to say 10k or 100k and see if there are any more improvements. Start with a low switching freq and work your way up. This way you will be able to identify where your circuit limitations are.
Remember you are FM modulating the signal. By definition FM have a infinite number of sidebands although sidebands having l
RF, Microwave, Antennas and Optics :: 01.07.2004 19:56 :: E-design :: Replies: 5 :: Views: 969
Hi,
If You are lucky enough, You can get an MC2833. That is an FM transmitter
chip.
Regards,
probert
Professional Hardware and Electronics Design :: 22.07.2004 15:42 :: probert :: Replies: 19 :: Views: 17709
Hi
I m working on remote controlled car where I requires FM modulator & Demodulator IC. Can anybody suggest IC no's that requires less hardware or a ckt that can be used in remote controlled vehicle.
Electronic Elementary Questions :: 30.03.2005 16:29 :: smartshashi :: Replies: 3 :: Views: 1860
The loop will try to remove the FM. Therefore the loop bandwidth should be lower than the lowest modulating frequency. Add your audio signal to the vco frequency control pin.
Analog Circuit Design :: 11.04.2005 17:59 :: flatulent :: Replies: 3 :: Views: 466
FSK ... FM ... same principle.
An F to V converter would work fine.
Another method is to lock onto the modulated signal with a PLL. The loop control voltage becomes your demodulated signal.
Electronic Elementary Questions :: 12.08.2005 04:48 :: echo47 :: Replies: 4 :: Views: 858
I am afraid that 100MHz oscillator is not suitable for this application ..
What you need is a small FM modulator and here is an example:
Regards,
IanP
RF, Microwave, Antennas and Optics :: 19.09.2005 14:04 :: IanP :: Replies: 4 :: Views: 1445
HI,...
I've made an FM transmitter at a frequency 87.8MHz using LC oscillator, I'm asking if I can get a crystal oscillator instead of the LC one.
Is it possilble.??????????
Yes possible..
If you design harmonic oscillator that will work at frequency of interest which is exact harmonic of crystal frequenc
RF, Microwave, Antennas and Optics :: 22.10.2005 02:17 :: BigBoss :: Replies: 4 :: Views: 2083
I am looking for material on ultra low distortion (< 0.05%), wide-band-analog FM modulation techniques, that does not involve any digital processing. I have done a lot of searching but could not really come up with anything useful.
I am doing a project on a high quality FM Stereo broadcast exciter and want to see how low I can get the distorti
RF, Microwave, Antennas and Optics :: 20.12.2005 21:54 :: E-design :: Replies: 6 :: Views: 602
RF, Microwave, Antennas and Optics :: 05.01.2006 09:26 :: vfone :: Replies: 45 :: Views: 13665
Look this:
And here are schematics of tuner and PLL.
RF, Microwave, Antennas and Optics :: 24.04.2006 05:35 :: Borber :: Replies: 2 :: Views: 1613
If a transmitter putting out an unmodulated carrier is significantly stronger at the receiver then a weaker signal carrying data then the receiver will just produce silence.
That is true for limiting amp - discriminator based detectors. If there is no overlapping of frequency spectrum of each transceiver obfuscating
RF, Microwave, Antennas and Optics :: 17.02.2006 17:09 :: artem :: Replies: 11 :: Views: 1483
hi
if you are borrowing an architecture and change your transistors to the need of your specs then you could first freeze the specs i.e. convert the system level specs into the circuit level specs from the models and the libraries you have for your design. This is for simulation.
i dont think there is a big deal in what i have said. if the arch
Analog IC Design and Layout :: 03.03.2006 06:44 :: shankar :: Replies: 10 :: Views: 2198
I am using FM,FSK.
which group is better?(linear?)
Can we use group 1 with PLL ICs?
RF, Microwave, Antennas and Optics :: 10.04.2006 21:51 :: 7rots51 :: Replies: 4 :: Views: 707
Your circuit is FM oscillator. Centre frequency depends on average value of modulating signal. Changing the bit rate causes different side band componnents. Higher the bit rate greater is the distance between sidebands. It is normal behaviour for FM.
All spectrum components are desirable. This is wide band FM. If you preffer smaler number of spect
RF, Microwave, Antennas and Optics :: 01.05.2006 23:19 :: Borber :: Replies: 17 :: Views: 1795
what about the current did u increase it , and see the phase noise performance
khouly
i will try it tomorrow ISA.
also i found some explaination in Dr. Emad Hegazi book it is great and have a complete chapter talking bout my problem but i could not upload it because it is so big but mainly the problem is from the non
Analog Circuit Design :: 29.05.2006 13:46 :: eng_islam :: Replies: 14 :: Views: 814
hi
The reason I want the varactor to be linear is that the frequency of the LC-tank vco is given by 2*pi*f= 1 / sqrt(LC(V). If the varactor C(V) relation is linear, the LC vco tunig curve will follow the inverse square law correctly. But obviously there are other effects, such as the AM-FM conversion that u mentioned that degrade the output fre
Analog Circuit Design :: 26.06.2006 18:46 :: saber890 :: Replies: 5 :: Views: 1268
Hi to forum
I want to make fm modulation to a 1.7 to 1.8 ghz pll . For this purpose i used adf4106 pll with umc vco . I though to drive the reference with dds signal at 40 mhz . My question is how to make fm modulation for fm bradcast signal . I can fm modulate the dds reference so this multiplied produces the needed 1.8 ghz fm modulation .
RF, Microwave, Antennas and Optics :: 18.09.2006 17:48 :: leonardo0 :: Replies: 2 :: Views: 1026
how to modulate a signal (FM) by using a PLL+vco system?
RF, Microwave, Antennas and Optics :: 22.09.2006 18:30 :: 7rots51 :: Replies: 3 :: Views: 1948
Hello
I need application note on this ICs:
MC13135 -----> FM RX system(Ant to voice in VHF band)
MC2833 -----> FM TX system(voice to Ant in VHF band)
Please reply the links.
Is there similar ICs for Tx/Rx of voice signal in VHF band(<=200MHZ) ?
RF, Microwave, Antennas and Optics :: 24.11.2006 15:39 :: 7rots51 :: Replies: 5 :: Views: 3734
What device are you using
I want to use any xilinx fpga
Why do u want to implement pll?
I want to build a fm modem
u can using the core gen to generate dll/dcm
Can dll/dcm be used in this project ( fm modem) ?
PLD, SPLD, GAL, CPLD, FPGA Design :: 16.03.2007 05:03 :: eelinker :: Replies: 9 :: Views: 8764
can i amke FM modulation using 74ls124?
if yes how can i make an effecient transmitter using it?
Analog Circuit Design :: 12.04.2007 13:46 :: mr_byte31 :: Replies: 3 :: Views: 887
Hi,
I'm using a 74HC4046A PLL/vco to demodulate mono audio from an FM carrier. The carrier comes from a signal on CAT5e twisted-pair cable. (it rides on the common-mode on one pair which carries video on the differential mode) The carrier frequency is about 250kHz and the amplitude seen by the receiver is about 250mVp-p. Currently I'm modulatin
Analog Circuit Design :: 27.04.2007 21:57 :: akilpatrick :: Replies: 0 :: Views: 597
you plz go to matlab central forum..file xchange..
in comm. section fm rx design is available...
Digital communication :: 13.08.2007 11:14 :: rag_perfect :: Replies: 3 :: Views: 2640
the main issue about the PLL and the DLL , is the DLL change the delay , but the PLL change the phase and frequency ,
if u want the DLL to change the freququncy , u should use an delay line , and a edge combiner , in this case the DLL can change frequency , so it can be used to demodulated the FM singal ,
u need to read about how DLL can be
ASIC Design Methodologies and Tools (Digital) :: 01.11.2007 11:20 :: khouly :: Replies: 9 :: Views: 684
then there isn't any problem with the oscillator part. actually i can't find any problem with the whole circuit! .
Your values are suspect. 8O
Your tank circuit is a 1uH to resonate with 40pF which will give a very low frequency. This will also give a low Q tank with bad stability and bad phase noise. I assume you need
Analog Circuit Design :: 31.12.2007 20:12 :: E-design :: Replies: 33 :: Views: 1990
Above statements are wrong. It is a receiver, simple but high sensitive and capable to demodulate AM and FM.
Analog Circuit Design :: 06.06.2008 05:09 :: Borber :: Replies: 64 :: Views: 8847
PLL FM demodulator
RF, Microwave, Antennas and Optics :: 07.09.2008 14:10 :: vfone :: Replies: 14 :: Views: 16910
im designing a phase locked loop as a FM demodulator using 74hc4046.
Can anyone explain to me what expected output at the output of phase detector and vco. The output signal that I get from vco is exacly the same as the input signal.
but oscilloscope show nothing at the output of the phase detector.
can anyone tell what might be the problem.
Analog Circuit Design :: 09.03.2010 05:31 :: f1kr1 :: Replies: 1 :: Views: 1030
HI dear
i need your help to create 2 pro in matlab coding
1-Real Time AM Modulation
2-Real Time FM Modulation
with input any voice signal
if any one can help me i wish from him doing that
with My Regards
Analog Circuit Design :: 10.03.2010 21:13 :: Eng_Mo7aMaD :: Replies: 2 :: Views: 2815
hi,
i am building a wireless data transmitter as major project in college, basically i am thinking to design a FM transmitter for transmitting serial data (at max 15 meters). i am using lmx2322 pll and vco (80-100 Mhz), can some one tell me if i put serial data(8 bit) at the input of the transmitter then can i get the serial data at the receiver
RF, Microwave, Antennas and Optics :: 06.11.2010 20:56 :: devil6600 :: Replies: 5 :: Views: 866
above circuit is fm receiver.
when i used pin supply 9V, this circuit had quite nice performence. But when i used AC/DC rectifier or switch supply on same pcb , the received audio has a tone ooeee (noise). I don't know why?
pls help
Analog Circuit Design :: 12.01.2011 08:10 :: contau :: Replies: 24 :: Views: 1575
use just vco function in 565
like fm demod: and envolope dettector(RC)
Analog Circuit Design :: 05.03.2011 17:55 :: ismailpp2008 :: Replies: 3 :: Views: 954
Hi, my name is Aloysius. My English isn't very good so please bare with me and I will do my best to make sense lol.
I am very new to radios but I have a strong interest in them. Although I have an basic understanding of how electrical components work I have
trouble putting it all together to make a working circuit. I would like to make an FM ra
RF, Microwave, Antennas and Optics :: 16.08.2011 13:21 :: aloysim :: Replies: 15 :: Views: 642
Hello everyone!!! I have a problem. I would like to perform phase demodulation using PLL. I have some matlab code that do that in the case of FM. Here is the code:
%This m-file demonstrates a PLL which tracks and demodulates an FM carrier.
clear all;
close all;
f=1000;%Carrier frequency
fs=100000;%Sample frequency
N=5000;%Number of samples
RF, Microwave, Antennas and Optics :: 02.11.2011 12:11 :: FFFPLL :: Replies: 0 :: Views: 387
You have not specified any parameters of the frequency-modulated signal, nor of the modulating signal.
If you already have a frequency synthesizer, you could modulate its frequency by applying the modulating signal to the control bits of the synthesizer. If you want to keep the synthesized carrier and apply a frequency modulation to it, then you c
RF, Microwave, Antennas and Optics :: 15.11.2011 17:53 :: jiripolivka :: Replies: 5 :: Views: 279
Hello everyone,
i don't have much experience in RF world but now i have to design some method of FM demodulation. Although i have read a few things on this topic, i still have some problems and would be really grateful for some help from somebody with bigger experience.
So...
I have this FM signal with parameters:
Carrier frequency: fc=
RF, Microwave, Antennas and Optics :: 27.11.2011 17:58 :: zigfryd :: Replies: 10 :: Views: 1142
HSP50210 is a Digital COSTAS Loop.You can use it to demodulate BPSK, QPSK, 8-PSK, OQPSK, FSK, AM and FM.
You should add a down-converter and an ADC before it.The LO for down-converter is not the one we need to recover.Only its phase noise should we need to care about,I think.
HSP50210 will recover the carrier which is used for demodulation.
RF, Microwave, Antennas and Optics :: 12.01.2012 05:12 :: torbai :: Replies: 15 :: Views: 260
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