| Author |
Message |
R110
Joined: 16 Oct 2001
Posts: 64
Location: Iran
|
 16 Oct 2001 8:40 |
|
|
|
Hi
I want to design a video switcher system, It should switch 12 input video signals.
Do any body have any shcematic circuit diagram or any other usefull info.
By the way if I want to design a video buffer with the IC AD826 , what configuration do you recomend?
|
|
| Back to top |
|
 |
padspcb
Joined: 28 Apr 2001
Posts: 273
Location: Earth
|
| 16 Oct 2001 9:31 |
|
|
|
Hi
I've seen some projects using simple cmos switches. they work.
with some simple circuit, an ye o'l cga controler and some ram you can also build an osd for time & channel. you can use a pic to display, switch, timer stuff etc.
there are many solutions for displaying multi channels, but deppends on cost.
|
|
| Back to top |
|
|
aNdreiBuuu
Joined: 30 Apr 2001
Posts: 398
Helped: 11
|
| 16 Oct 2001 11:30 |
|
|
|
Use M(at)xim video switches... worksgreat, and U'll see on m(at)xim page some app notes.
if U want to use simple cmos switches u'll need 3 for each channel and a Not gate one in the middle coupled to earth and the other 2 at in and out...
//a
|
|
| Back to top |
|
|
R110
Joined: 16 Oct 2001
Posts: 64
Location: Iran
|
| 16 Oct 2001 12:53 |
|
|
|
I've seen a professional video switcher manufactured by sony, called PRESELECTOR.
I my design I 've used a buffer network ( using AD826 as a video buffer) and a switch network ( using two analog switcher 74hct4051 that are controlled by microcontroller 8951 and a video amplifier for amplify the gain of the signal.
My problem is that there is not any good video buffer IC . so that I have to use AD826 because I can make the buffer network by using just 8 of them. I'm looking for a suitable circuit diagram of a video buffer
Do you have any suggestion?
By the way, thanks for your replys
|
|
| Back to top |
|
|
aNdreiBuuu
Joined: 30 Apr 2001
Posts: 398
Helped: 11
|
| 16 Oct 2001 13:20 |
|
|
|
take a look at:
h**p://para.m(at)xim-ic.com/compare.asp?Fam=Vid_Buff&Tree=Amps&HP=AmpComp.cfm&SORD=190&FT_190=1094&ITEMLIST=110343,110356,110360,110362,110363,110364
//a
|
|
| Back to top |
|
|
R110
Joined: 16 Oct 2001
Posts: 64
Location: Iran
|
| 17 Oct 2001 10:33 |
|
|
|
Hi
Thanks alot, it was wonderful. Now I have a new question.
I've encountered with a kind of RF noise when I was testing my system, I think this noise was because of the enviroment's radiation. How can I solve this problem?
Do you have any recomendation?
Kind regards
|
|
| Back to top |
|
|
Dragon
Joined: 23 Jul 2001
Posts: 11
|
| 19 Oct 2001 11:09 |
|
|
|
Hi R110.
I used a Maxim Ic Max440 and I have similar problems of noise, and I put a 75R resistor to unused inputs and the problem was solved.
|
|
| Back to top |
|
|
R110
Joined: 16 Oct 2001
Posts: 64
Location: Iran
|
| 20 Oct 2001 8:33 |
|
|
|
I've used 75 ohm resistor, it does not solved this problem . when I test it in laboratory there is no noise, But in the main room it has problem of noisi.
Thank you very much for your attention any way.
[ This Message was edited by: R110 on 2001-10-20 09:35 ]
|
|
| Back to top |
|
|
