sonicmook56
Well-known member
Here at the studio, I found it annoying to switch inputs to a video monitor and external console inputs, between a DVD player and a satellite recever.
First you had to patch the video, then patch the audio, then hit an external select switch on the console.
I came up with this little box that takes the unalanced audio output and ballances it, as well as take the audio and video and switches it via toggle switch.
Before I explain my video problem, I just want to say that I have never worked, or even thought about a video circuit. The circuit in question is straight from the Mfg. demo board layout.
http://datasheets.maxim-ic.com/en/ds/MAX4313EVKIT.pdf
So I decided to go with a MAX4313 to switch the video. (still not sure why this IC is better than an simple switch) Testing difftent sources with this gives me diffrent results on the output... I'm sure I'm missing somthing fundamental
Satallite recever: Looks good on the monitor
DVD: hardly anything, black and white all distorted. If I remove one of the 49.9ohm resistors, I get a picture, but it's very washed out "white"
I tested it on another DVD player and had the same results.
I looked at the NTSC on my scope and noticed a diffrent offest on the good signal, compared to the bad signal..
I checked the DC offset of the satallite recever, and it was around .6Vdc
The DVD player in question was at 0v
Could this be an input bias problem, input capactance?
Again, I'm sure I'm missing somthing fundamental here and I have no idea what I'm doing video wise.
The audio part of the circut measures .00063 thd. Nice and clean.
:sam: :sam: :sam: :sam:
First you had to patch the video, then patch the audio, then hit an external select switch on the console.
I came up with this little box that takes the unalanced audio output and ballances it, as well as take the audio and video and switches it via toggle switch.
Before I explain my video problem, I just want to say that I have never worked, or even thought about a video circuit. The circuit in question is straight from the Mfg. demo board layout.
http://datasheets.maxim-ic.com/en/ds/MAX4313EVKIT.pdf
So I decided to go with a MAX4313 to switch the video. (still not sure why this IC is better than an simple switch) Testing difftent sources with this gives me diffrent results on the output... I'm sure I'm missing somthing fundamental
Satallite recever: Looks good on the monitor
DVD: hardly anything, black and white all distorted. If I remove one of the 49.9ohm resistors, I get a picture, but it's very washed out "white"
I tested it on another DVD player and had the same results.
I looked at the NTSC on my scope and noticed a diffrent offest on the good signal, compared to the bad signal..
I checked the DC offset of the satallite recever, and it was around .6Vdc
The DVD player in question was at 0v
Could this be an input bias problem, input capactance?
Again, I'm sure I'm missing somthing fundamental here and I have no idea what I'm doing video wise.
The audio part of the circut measures .00063 thd. Nice and clean.
:sam: :sam: :sam: :sam: