Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: airman00 on April 07, 2008, 05:21:37 PM

Title: Line level input?
Post by: airman00 on April 07, 2008, 05:21:37 PM

Over here by the DTMF  decoder  it says the following
" Onboard RCA audio input jack for line level inputs "

Now what exactly does that mean ?

I want to connect the decoder to the headphone jack of an MP3 player  using this adapter
(http://www.vpi.us/vpi/images/items/sam-2rcam-05.jpg)

Do MP3 players give out line level outputs, or would I need an amp for it?
I have a feeling I would need an amp , but if I do need one , can I just use a standard op amp?

Title: Re: Line level input?
Post by: AndrewM on April 07, 2008, 10:56:33 PM

http://www.transom.org/tools/basics/200207.analogbasics.html

Most electronics, except for standard microphones, output at line level.

Title: Re: Line level input?
Post by: Admin on April 14, 2008, 06:48:38 PM

Quote

if I do need one , can I just use a standard op amp?

There are op-amps specifically designed for audio applications. When you browse the digikey selection, it will have that option.

Title: Re: Line level input?
Post by: Soeren on April 15, 2008, 08:48:28 AM

Hi,

Quote from: airman00 on April 07, 2008, 05:21:37 PM

" Onboard RCA audio input jack for line level inputs "

Now what exactly does that mean ?

Line Level used to be a standardized measure (although different in the consumer range and eg. broadcasting) - for consumer goods, which this project is probably referring to, Line level is 775mV RMS.

These days, the term has been watered down to the point of near distinction, trough the multitude of far east products where "Line Level" can be anything from 100mV to 2V.

Even so, when you meet the term, at least you know that a microphone won't do :D