Analog Spectral inversion

does anyone know to to spectrally invert a SSB(single side band)
signal both in baseband and passband.


 from  /�   to   �\

Thanks
 
ch

C H wrote:

> does anyone know to to spectrally invert a SSB(single side band)
> signal both in baseband and passband.
> 
> 
>  from  /�   to   �\
> 
> Thanks
>  
> ch

If you write what you mean by inverting it at baseband, I'll go into
detail. (That sort of operation is done in analog voice scramblers.)

Jerry
-- 
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������

Jerry Avins wrote:

> C H wrote:

>> does anyone know to to spectrally invert a SSB(single side band)
>> signal both in baseband and passband.

(snip)

> If you write what you mean by inverting it at baseband, I'll go into
> detail. (That sort of operation is done in analog voice scramblers.)

I think baseband would mean converting all positive frequencies
to negative frequencies.  As that was discussed some year ago,
I hope it doesn't start a long discussion again.

Otherwise, doubly balanced modulators are what I would
have expected.

-- glen

glen herrmannsfeldt wrote:

> Jerry Avins wrote:
> 
>> C H wrote:
> 
> 
>>> does anyone know to to spectrally invert a SSB(single side band)
>>> signal both in baseband and passband.
> 
> 
> (snip)
> 
>> If you write what you mean by inverting it at baseband, I'll go into
>> detail. (That sort of operation is done in analog voice scramblers.)
> 
> 
> I think baseband would mean converting all positive frequencies
> to negative frequencies.  As that was discussed some year ago,
> I hope it doesn't start a long discussion again.
> 
> Otherwise, doubly balanced modulators are what I would
> have expected.
> 
> -- glen

That's one possible meaning. (It would sound normal) Another is what you
would get by translating a lower sideband so that its lower band edge
just reaches DC and the [possibly absent] carrier is at the upper edge
baseband. That's a primitive scrambler.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������

C H wrote:
> does anyone know to to spectrally invert a SSB(single side band)
> signal both in baseband and passband.
> 
> 
>  from  /�   to   �\
> 
> Thanks
>  
> ch
You could try recovering the double side bands, surpresss the higher 
side band, and then remodulate at the original carrier.

Stan Pawlukiewicz wrote:

> C H wrote:
> 
>> does anyone know to to spectrally invert a SSB(single side band)
>> signal both in baseband and passband.
>>
>>
>>  from  /�   to   �\
>>
>> Thanks
>>  
>> ch
> 
> You could try recovering the double side bands, surpresss the higher 
> side band, and then remodulate at the original carrier.

Presumably, /� represents carrier and lower sideband, �\ represents
carrier and upper sideband, with the presumption that the carrier is
suppressed (broken bar). With carrier, they might be /|, |\, with AM
being /|\. What are we to suppose that the OP means by /� at baseband?

Jerry
-- 
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������

Jerry Avins wrote:
> Stan Pawlukiewicz wrote:
> 
>> C H wrote:
>>
>>> does anyone know to to spectrally invert a SSB(single side band)
>>> signal both in baseband and passband.
>>>
>>>
>>>  from  /�   to   �\
>>>
>>> Thanks
>>>  
>>> ch
>>
>>
>> You could try recovering the double side bands, surpresss the higher 
>> side band, and then remodulate at the original carrier.
> 
> 
> Presumably, /� represents carrier and lower sideband, �\ represents
> carrier and upper sideband, with the presumption that the carrier is
> suppressed (broken bar). With carrier, they might be /|, |\, with AM
> being /|\. What are we to suppose that the OP means by /� at baseband?
> 
> Jerry

DC ?


Your guess is as good as mine.

# Jerry Avins

> C H wrote:
> 
>> does anyone know to to spectrally invert a SSB(single side band)
>> signal both in baseband and passband.
>> 
>> 
>>  from  /�   to   �\
>> 
>> Thanks
>>  
>> ch
> 
> If you write what you mean by inverting it at baseband, I'll go into
> detail. (That sort of operation is done in analog voice scramblers.)
> 
> Jerry

I'm curious: What is the audible effect of inverting the frequency, say 
mirroring it about it's average, so a voice signal's upper frequency of ~
8kHz becomes 100Hz, and it's first fundamental of ~100Hz becomes 8kHz?

I'm having difficulty imagining it.

-- 
Toby
asktoby.com
BSOD VST & ME

On 29 Apr 2004 10:15:45 GMT, Toby Newman <google@asktoby.com> wrote:

>I'm curious: What is the audible effect of inverting the frequency, say 
>mirroring it about it's average, so a voice signal's upper frequency of ~
>8kHz becomes 100Hz, and it's first fundamental of ~100Hz becomes 8kHz?
>
>I'm having difficulty imagining it.

Just get a hold of any shortwave receiver with BFO capability and have
a listen.  Go to the 40m or 20m ham bands and tune in a voice station
"properly".  Then tune in the direction that makes the pitch of the
voice sound lower.  Keep going in that direction until the pitch sound
about in the same range as before.  You are now listening to
pitch-inverted audio.  It sounds all messed up.


-Robert Scott
 Ypsilanti, Michigan
(Reply through this forum, not by direct e-mail to me, as automatic reply address is fake.)

Toby Newman wrote:
>
> I'm curious: What is the audible effect of inverting the frequency, say 
> mirroring it about it's average, so a voice signal's upper frequency of ~
> 8kHz becomes 100Hz, and it's first fundamental of ~100Hz becomes 8kHz?

Rather strange and tinny, I suppose. It would imply a mirror frequency
of 4050 Hz and would put most of the voice energy just below 8kHz
which will make it sound rather harsh.

Noticing that you're also in the VST business: you can do that sort of
thing with our Magenta VST Plug in, btw.

--smb