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Conference wrksys::alphastation

Title:	Alpha Workstation Conference
Notice:	See note 1.* for conference notices
Moderator:	WRKSYS::HOUSE

Created:	Wed Sep 07 1994
Last Modified:	Fri Jun 06 1997
Last Successful Update:	Fri Jun 06 1997
Number of topics:	1996
Total number of notes:	9122

1822.0. "AlphaStation Tone Generator support Volume Control ?" by PEACHS::BECHTOLD () Mon Jan 27 1997 22:26

    A hopefully quick question.
    
    	I have found several notes referencing the AlphaStation Tone
    Generator/Bell implementation. I have 1 question on this.
    
    - Does the Tone Generator hardware of the AlphaStations support a
      Volume control ?
    
    	My understaning is that it's implemented as taking a square wave
    input for a specified duration to generate a Tone/Pitch. Can the
    hardware support varying the volume of the Tone ?
    
    Or by nature are Tone Generators only capable of producing a Tone for a
    specified duration ?
    
    I ask because neither Digital Unix or OpenVMS on these platforms have
    an interface for controlling Volume of the system bell. They only
    control the Tone/Pitch and the Duration.
    
    Any help is appreciated.
    
    Dave Bechtold
    DTN 343-1216

T.R	Title	User	Personal Name	Date	Lines
1822.1	Square wave	BGSDEV::MORRIS	Tom Morris - Light & Sound Engineering	`Tue Jan 28 1997 00:27`	8
	It's a square wave that is 100% on or off. The volume/ perceived volume/annoyance will vary as a function of the frequency, but nothing else. This isn't a characteristic of tone generators per se, but rather the original IBM PC implementation of one. Tom
1822.2		STAR::KLEINSORGE	Frederick Kleinsorge	`Tue Jan 28 1997 09:52`	6
	A variable resistor spliced into the speaker wire works ;-) It would be nice if someone put in a programmable gain control on the output.
1822.3	Thanks :^)	PEACHS::BECHTOLD		`Tue Jan 28 1997 09:55`	9
	Hi Tom, Thanks for the quick answer ! Dave Bechtold
1822.4	History of tone generator	STAR::JACOBI	Paul A. Jacobi - OpenVMS Development	`Tue Jan 28 1997 10:59`	8
	Note that the tone generator was originally part of the cassette tape record/playback interface of personal computers from the late 1970s. After floppy disks finally became affordable (<$1000), the tone generator was then used as a crude sound generator for the first BASIC computer games. It was later found incapable of complex digital audio, so the circuit was reduced to simply the keyboard bell.
1822.5		STAR::KLEINSORGE	Frederick Kleinsorge	`Tue Jan 28 1997 12:39`	6
	And the real stupidity is that the KB bell should be in the KB, not the system box. But to save a buck, IBM has handed us a heritage that makes no sense today.