41 Threads found on edaboard.com: Fm Using Vco
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 04:55 :: sanam86 :: Replies: 0 :: Views: 373
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 02:42 :: mudrik :: Replies: 2 :: Views: 1147
I am trying to build an FM transmitter with PLL that can broadcast on 88.0Mhz to 108.0Mhz in 0.1Mhz increment, but I am not sure how to start building it.
Some questions that I have;
1) Is there any link or book that I can read about how to design this kind of project, or give out schematic?
2) Do I have to build an FM tran
Hobby Circuits and Small Projects Problems :: 09.06.2006 04:56 :: spacecowboy :: Replies: 6 :: Views: 3818
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 08:22 :: ex4 :: Replies: 0 :: Views: 698
I need to design FM MODULATOR BY using PLL but without using any IC or Chip.
I need to build the circuit and examine it on the oscilloscope only.
thank you in advance for any help..
Analog Circuit Design :: 31.05.2011 18:54 :: LEARNING2 :: Replies: 18 :: Views: 2258
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:
|..4046..|---->/--------| |------ Audio in
Professional Hardware and Electronics Design :: 28.06.2002 13:03 :: penrico :: Replies: 3 :: Views: 1193
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 04:40 :: tipet20002000 :: Replies: 10 :: Views: 6438
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 09:29 :: smartshashi :: Replies: 3 :: Views: 2069
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 11:59 :: flatulent :: Replies: 3 :: Views: 580
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 :: 11.08.2005 22:48 :: echo47 :: Replies: 4 :: Views: 1110
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.??????????
RF, Microwave, Antennas and Optics :: 21.10.2005 18:00 :: seadolphine2000 :: Replies: 4 :: Views: 2618
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 15:54 :: E-design :: Replies: 6 :: Views: 717
And here are schematics of tuner and PLL.
RF, Microwave, Antennas and Optics :: 23.04.2006 23:35 :: Borber :: Replies: 2 :: Views: 1913
Linear tuning usually means that they are using a varactor diode that tunes roughly linearly with frequency, that is a delta 1 V yields pretty much the same delta F at both the low and high end of the operating band. So if you are sending data by FM, you can get pretty much the same frequency deviation independent of operating frequency.
RF, Microwave, Antennas and Optics :: 09.04.2006 19:58 :: biff44 :: Replies: 4 :: Views: 891
how to modulate a signal (FM) by using a PLL+vco system?
RF, Microwave, Antennas and Optics :: 22.09.2006 12:30 :: 7rots51 :: Replies: 3 :: Views: 2555
The maximum frequency of the 74ls124 vco is about 30MHz. So if you need a transmitter in the FM broadcast band, you need a bandpass filter tuned to a vco harmonic.
As an RC oscillator, 74ls124 is not very stable and may be very noisy to use as an FM modulator. The control and power voltage should be very well filtered, else the power supply noise
Analog Circuit Design :: 12.04.2007 08:06 :: Eugen_E :: Replies: 3 :: Views: 1134
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 15:57 :: akilpatrick :: Replies: 0 :: Views: 753
you plz go to matlab central forum..file xchange..
in comm. section fm rx design is available...
Digital communication :: 13.08.2007 05:14 :: rag_perfect :: Replies: 3 :: Views: 3010
Can someone explain or point me to the right link on how a PLL is used to demodulate a FM carrier? Every book I read tells me it can be done but not specific enough on how it is done. I have read Horowitz & Hill: The Art of Electronics 2nd edition and RF Engineering for Wireless Networks by Daniel M. Dobkins.
RF, Microwave, Antennas and Optics :: 05.09.2008 16:52 :: robismyname :: Replies: 14 :: Views: 18097
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 :: 08.03.2010 23:31 :: f1kr1 :: Replies: 1 :: Views: 1262
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 15:56 :: devil6600 :: Replies: 5 :: Views: 1066
I am afraid that you cannot FM modulate the internal vco. Seems that is no access to the resonant circuit.
You can try using an external vco, the chip allowing for this option.
RF, Microwave, Antennas and Optics :: 04.01.2011 12:40 :: vfone :: Replies: 23 :: Views: 2175
use just vco function in 565
like fm demod: and envolope dettector(RC)
Analog Circuit Design :: 05.03.2011 11:55 :: ismu :: Replies: 3 :: Views: 1278
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.
N=5000;%Number of samples
RF, Microwave, Antennas and Optics :: 02.11.2011 07:11 :: FFFPLL :: Replies: 0 :: Views: 754
I am using MAX2606 as the vco of my FM modulator project after I got lot of suggestions to use it from edaboard members. :smile:
For frequency stability there is a PLL in this modulator. But this vco has a single fixed oscillation frequency which is determined by the external inductance connected to pin #1.
Since my FM modulator has (...)
RF, Microwave, Antennas and Optics :: 21.05.2012 08:10 :: dumindu89 :: Replies: 3 :: Views: 638
With the add of Frequency Locked Loop (FLL) to the standard PLL loop catch faster the nominal frequency. One, the most important fact is that while FLL has dominante role in combined loop the phase noise of vco is much lower.
FLL is an old technik of stabilizing frequency of oscillators. It can be realized using analog frequency discriminator like
Electronic Elementary Questions :: 11.10.2004 14:25 :: Borber :: Replies: 3 :: Views: 1172
Nice link decfm. Instead of PLL why not you go for DDS chip it will be easy as compared to PLL based design.
Hobby Circuits and Small Projects Problems :: 06.06.2006 14:17 :: Code Warrior :: Replies: 6 :: Views: 3556
What frequency are we talking about here?
The simplest way to get FSK modulated carrier frequency is to FM modulate the vco (LC oscillator with varactor diode) with a (digital) squarewave signal. But this design will probably need PLL control for frequency stability, so its complicated for unexperienced designer.
Perhaps a better way and stil
Electronic Elementary Questions :: 05.03.2005 19:38 :: rfmw :: Replies: 3 :: Views: 996
Personally I wouldn't use CD4046 as FM-demodulator. So far I haven't come across even one properly working demodulator based on this IC.
Different story with ICs such as NE564: always works veery well and you can find plenty of applications and diagrams on the web.
Anyhow, if you would like to continue with 4046 could you pkease advice your con
RF, Microwave, Antennas and Optics :: 07.03.2005 00:19 :: IanP :: Replies: 1 :: Views: 3605
the PLL has many application
about ur question u have a vco with 2 GHz , and the phase detector to detect the phse difference between thr vco and Xtal oscillaot "there is no Xtal oscillator running in 2 GHz"
but between the vco and phase detector we usually insert a frequncy divider
and this called Frequncy synthizer
there are (...)
Analog Circuit Design :: 01.04.2006 04:27 :: khouly :: Replies: 4 :: Views: 3026
u can use the singal to modulate the vco and then u get FM signal , then in reciver u need FM demodulator to extract the signal
or u better convert the signal into digital data by DAC , anf then send it using ISM band chip TX , RX , the digital modulation can be FSK , ASK
there are many RF chips working in ISM band , check ti , and analog de
RF, Microwave, Antennas and Optics :: 22.08.2006 18:20 :: khouly :: Replies: 2 :: Views: 970
When using an IDEAL vco in VerilogA to generate a frequency modulated signal, then the instantaneous frequency of that signal is proportional to the modulating input signal. When using VerilogA to measure the period of the FM signal and thus finding the frequency I can sample these values and export them to Matlab to do an FFT. (...)
Analog Circuit Design :: 08.05.2007 00:50 :: svensl :: Replies: 0 :: Views: 710
mitgrace is forgetting to say that he needs to systhesize FM band (roughly 100MHz). He will use 3GHz vco most probably to integrate vco tank in IC (we had past discussions in another topic). So the ratio FLO/FREF is not so high.
Analog IC Design and Layout :: 05.01.2008 03:12 :: Mazz :: Replies: 9 :: Views: 1405
Hi No one
I think the easiest way for implementation of FM modulator is using varactor diods(vco) with a simple oscillator such as colpitts
RF, Microwave, Antennas and Optics :: 08.08.2009 07:17 :: ali110 :: Replies: 2 :: Views: 658
You can not double (using a frequency multiplier) the DVB-T signal because uses QPSK, 16QAM or 64QAM modulations, which are not constant envelope.
Only signals using constant envelope modulations as FM, GMSK, GFSK, etc. could be doubled, without distorting the data.
RF, Microwave, Antennas and Optics :: 16.12.2009 11:23 :: vfone :: Replies: 7 :: Views: 1578
Dose anyone know wheather phase noise is included in the phase noise
simulation result in spectre ?
Not sure what this means
I saw a peak at the freqeucy of (fo - fm) .
Can you provide more details, what is fo, fm, whether you are simulating the closed loop PLL or just the vco, etc
Analog Circuit Design :: 11.01.2010 01:32 :: saro_k_82 :: Replies: 1 :: Views: 1581
For FM demodulation: If modulation index is low (max. phase deviation less than 1 radian), you could use a narrow-band PLL as a phase demodulator. The output is the ouput of the phase detector, that after derivation gives the frequency.
This can work for low-index FM but not for FSK.
Why do you need a method other than take the control voltage o
Analog IC Design and Layout :: 22.02.2010 11:36 :: zorro :: Replies: 1 :: Views: 1222
I am about to finish my 80 MHz Quartz Crystal vco, but I am not confident on Jitter's results. Please try to answer these questions, as fast as you can, as I have the tape-out in August of the full PLL:
1 - For the vco circuits (autonomous circuits), which jitter measurement type should I use: FM or PM (I am using FM)? I think we (...)
Analog Circuit Design :: 12.05.2011 03:55 :: netbug :: Replies: 0 :: Views: 621
any particular reason why you want to use AM ? FM is much easier to generate and demodulate
I have gear on many freq's from 1GHz through to 24GHz and FM is my mode of choice unless I'm
doing very weak signal work where I will use either SSB or CW
RF, Microwave, Antennas and Optics :: 24.11.2011 16:31 :: davenn :: Replies: 7 :: Views: 647
AM receivers operate at a low frequency (<30 MHz) where frequency stability is not an issue. Therefore there are no AFC circuits used to pull the receiver to a selected AM signal.
In FM receivers that operate at >80 MHz, oscillators are unstable. Therefore AFC circuit was invented to pull receiver oscillator to the FM spectrum center, to optimize t
RF, Microwave, Antennas and Optics :: 28.03.2012 12:55 :: jiripolivka :: Replies: 6 :: Views: 334
You can make an FLL, but you will always get some frequency difference because of offset issues. In a PLL you may get a steady phase offset, but there will be zero frequency offset.
The "modern" phase comparators function as frequency comparators when out of phase lock and behave as phase comparators when phase synchronized. This saves you fr
Analog Circuit Design :: 20.09.2012 18:08 :: WimRFP :: Replies: 3 :: Views: 337