ok... i got myself a TV card a while ago, and it works fine, expet for one thing: the line out signal (sound) it a little noisy it's basicly white noise and a low frequent humm... is there a easy way to make some sort of passive filter to remove this noise? will a capacitor make any difference?
YMMV but it often works on Hi-Fi...if the computer and TV are both grounded, using a screened cable grounded at one end only stops earth loops.
Uh cpemma, he's talking about a TV Tuner card, one that probably goes into the PCI slot. They require a patch cable that goes between TV Line-Out and sound card Line-In. As for how to eliminate noise, I can't help you with any electrical way to do it, but one thing that I know helps is to keep it away from any other cables, especially ones that carry AC power (power cord) or at a high frequency. It's ok if the cards are perpendicular to each other, but in parallel you'll have EM Interference.
You could make a simple noise gate by putting two diodes, in opposite polarity, using the loss in the diode to cut out the noise, though the loss might be a bit much, though if it is a high impedance connection, it won't matter as much (I think) than if it were low impedance. If it is a ring at a specific frequency, you could get a capacitor and an inductor to get rid of it, but if it is white noise, it is broad spectrum and hard to remove. Using a telescoping shield for ground loops, like Cpemma suggested only works on floating/balanced audio connections. getting rid of humming and such is probably the hardest thing to do in audio equipment setups.
i had the exact same problem with a TV tuner card; you need to get a cable that goes (inside your computer) between the tv tuner card and the sound card... simple as that...
problem is that my tv-vard dont have an internal connector... i tries to seperate the ground, but it didn't help...
You could probably 'hack' one in however. What you'd want to do is find the traces on the board that go to the line out, and trace them back to the chip. At that point you could just run another wire from the chip.
nah... that would look ugly... besides, i'm noy fancy soldering wires on that chip... way to easy to tear off the traces
simply looping the patch cable may help some, I remember reading an article somewhere about this. dunno for sure tho since I dont have any noisy equipment to test it on
Ok.. i have vome a step further now... i figured out that if i disconnected ground the noise disappeared... (the signal comes from cable TV) What i have done now is that i have cut the shielding and soldered in a capacitor (smal ceramic (SP?))... It took care of the noise, but now the picture is a bit grainy (SP?)... I also tried to cut the shielding and put the shielding back on the cable so that it had a bit overlap (insulated between).. the Picture got completely useless then... my question now is: is there a way of connecting the cable ground and chassie ground together, or are these already connected together? Should i put a cap between ground and signal instead? (still talking about the coax for cable TV) it seems like i need some sort of equalisation (is that a word?) between cable TV ground and chassie ground... (sorry about the messy post.. it's getti'n late)
