Caple C871i Bedienungsanleitung PDF herunterladen (Seite 89)

100

101

Apple II Computer Info

adapter, though (explanation follows):

Analog

In ---------------+------------+----+----------||------ >>

| | | 10-500 microfarad

-+- -+- + capacitor To CD player,

5V Zener /_\ Signal /_\ = 1.5V Battery microphone,

diode | Diode | - etc.

GS | | |

Ground -------------+------------+----+------------------ >>

[end quote]

but I changed it to this (a better ascii rendition of the circuit is

available!):

Analog 100 uF

In ---------------+------------+----+---------+--------||------ >>

| | < +

-+- -+- +-----+ > 10K To CD player,

5V Zener /_\ Signal /_\ = 3V < < microphone,

diode | Diode | - ><-+ etc.

GS | | | < 10K pot

Ground -------------+------------+----+-----+-------------------- >>

The Ensoniq is designed to handle 0 to 2.5V input, but audio sources usually

swing more or less equally +/- about zero. Therefore we need a level shifter,

to put the appropriate DC bias onto the input. The 3V battery and the 10K pot

are for this. To stop the low internal impedence of the battery effectively

shorting the sound source (which happens with the first circuit), I've included

another 10K resistor. The easy way to set this up is to use a program like

AudioZap and with the CD etc. end input shorted, set the centreline of the

oscilloscope display to be halfway up the screen, so the input signal will

swing equally either side of this reference voltage. The zener diode is to clip

the top of spikes to limit them to about 5V and the signal diode is to clip any

negative going signal to -0.6V. This is protect the Ensoniq chip from overload.

The capacitor keeps the DC out of the source. Pin one on the GS connector is

closest to the *front* of the computer (ie with the expansion slots at the

back.

The Ensoniq has a fairly low input impedence (about 3-5K), but most portable

cassette or CD players should be able to handle this, since most headphones

have a much lower impedence than this (usually around 50 to 100 ohms, even as

low as eight for old ones). You can use a tape deck as an amplifier and

"impedence buffer" for a microphone.

If you can get the file

http://cassius.ee.su.oz.au/~adrianw/gsaudioin.bsq

there's proof there that it all works (a raw sound file I made).

Adrian.

ps does anyone else hate the tabs that open the 2gs case as much as I do? I

always hurt my fingers trying to push them in enough to get the lid off.

Apple II Computer Technical Information : Apple II Family Hardware Info

ftp://ground.ecn.uiowa.edu/2/apple2/miscinfo/hardware : May 2001 : 89 of 572

1 2 ... 84 85 86 87 88 89 90 91 92 93 94 ... 571 572

Caple C871i Bedienungsanleitung Seite 89

Kommentare zu diesen Handbüchern

Caple C871i Bedienungsanleitung Seite 89

Kommentare zu diesen Handbüchern

Verwandte Produkte und Handbücher für Kochfelder Caple C871i