[sdiy] frequency shifters...

[Ken Stone]

I found a tube circuit that supposedly does this 90 degree shift across the
whole range the other day - I think from a Wurlitzer vibrato actually.

Ken

>The tricky part of the Frequency Shifter is to get the audio signals 90 degrees
>apart (in phase) over the audio range.  The usual method is called a "dome
filter"
>which are two, stagger tuned allpass networks.  The idea is that although
the overall
>phase shift may be hundreds of degrees (or thousands), that the difference
at any
>one frequency is precisely 90 degrees.
>
>Juergen Haible has some schematics on his site... IMHO you have to want a
frequency shifter REAL bad... its a pretty complex project !!!
>
>H^) harry
>
>Ordeish at aol.com wrote:
>
>>  thankyou all for your explanations and help. I think i have a basic
understanding of frequency shifting now.
>>  Now I will try to accomplish something similiar to wht John Marshall had
explained in his post using ring modulators to achieve the frequency shifting.
>>  thankyou all.
>>
>> edward s.
>
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_______________________________________________________________________
Ken Stone   sasami at hotkey.net.au  
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