>> In article <m3d3qajfy6.fsf@ieee.org>, Randy Yates <yates@ieee.org> wrote:
>>>spope33@speedymail.org (Steve Pope) writes:
>>>
>>>>>if you were designing a decimation filter for a baseband wcdma signal
>>>>>that was oversampled, what target (decimated) bandwidth would you
>>>>>choose?
>>>>
>>>> Somewhere between 2.5 MHz and 4 MHz at baseband?
>>>
>>>How could it possibly be 2.5 MHz? The chip rate is 3.84 Mc/s.
>> You said "at baseband".
>> We could get into a philosophical discussion as to what
>> "2.5 MHz bandwidth at baseband" means, but I meant each
>> of the I and Q channels has a bandwidth from 0 to 2.5 MHz.
>
>Doh! Right. (I was thinking of complex bandwidth).
>
>I agree with 2.5 (5 MHz complex) based on a chip rate of 3.84 Mc/s
>and (according to the 3GPP spec) a RRC rolloff factor of 0.22. Is
>that where your numbers come from?
That's approximately my thinking.
Steve
Reply by Randy Yates●November 12, 20102010-11-12
spope33@speedymail.org (Steve Pope) writes:
> In article <m3d3qajfy6.fsf@ieee.org>, Randy Yates <yates@ieee.org> wrote:
>>spope33@speedymail.org (Steve Pope) writes:
>>
>>>>if you were designing a decimation filter for a baseband wcdma signal
>>>>that was oversampled, what target (decimated) bandwidth would you
>>>>choose?
>>>
>>> Somewhere between 2.5 MHz and 4 MHz at baseband?
>>
>>How could it possibly be 2.5 MHz? The chip rate is 3.84 Mc/s.
>
> You said "at baseband".
>
> We could get into a philosophical discussion as to what
> "2.5 MHz bandwidth at baseband" means, but I meant each
> of the I and Q channels has a bandwidth from 0 to 2.5 MHz.
Doh! Right. (I was thinking of complex bandwidth).
I agree with 2.5 (5 MHz complex) based on a chip rate of 3.84 Mc/s
and (according to the 3GPP spec) a RRC rolloff factor of 0.22. Is
that where your numbers come from?
--
Randy Yates % "So now it's getting late,
Digital Signal Labs % and those who hesitate
mailto://yates@ieee.org % got no one..."
http://www.digitalsignallabs.com % 'Waterfall', *Face The Music*, ELO
Reply by Randy Yates●November 12, 20102010-11-12
Randy Yates <yates@ieee.org> writes:
> spope33@speedymail.org (Steve Pope) writes:
>
>> In article <m3d3qajfy6.fsf@ieee.org>, Randy Yates <yates@ieee.org> wrote:
>>>spope33@speedymail.org (Steve Pope) writes:
>>>
>>>>>if you were designing a decimation filter for a baseband wcdma signal
>>>>>that was oversampled, what target (decimated) bandwidth would you
>>>>>choose?
>>>>
>>>> Somewhere between 2.5 MHz and 4 MHz at baseband?
>>>
>>>How could it possibly be 2.5 MHz? The chip rate is 3.84 Mc/s.
>>
>> You said "at baseband".
>>
>> We could get into a philosophical discussion as to what
>> "2.5 MHz bandwidth at baseband" means, but I meant each
>> of the I and Q channels has a bandwidth from 0 to 2.5 MHz.
>
> Doh! Right. (I was thinking of complex bandwidth).
>
> I agree with 2.5 (5 MHz complex) based on a chip rate of 3.84 Mc/s
> and (according to the 3GPP spec) a RRC rolloff factor of 0.22. Is
> that where your numbers come from?
PS: And just rounding from 4.685 to 5.
--
Randy Yates % "Rollin' and riding and slippin' and
Digital Signal Labs % sliding, it's magic."
mailto://yates@ieee.org %
http://www.digitalsignallabs.com % 'Living' Thing', *A New World Record*, ELO
Reply by Steve Pope●November 12, 20102010-11-12
In article <m3d3qajfy6.fsf@ieee.org>, Randy Yates <yates@ieee.org> wrote:
>spope33@speedymail.org (Steve Pope) writes:
>
>>>if you were designing a decimation filter for a baseband wcdma signal
>>>that was oversampled, what target (decimated) bandwidth would you
>>>choose?
>>
>> Somewhere between 2.5 MHz and 4 MHz at baseband?
>
>How could it possibly be 2.5 MHz? The chip rate is 3.84 Mc/s.
You said "at baseband".
We could get into a philosophical discussion as to what
"2.5 MHz bandwidth at baseband" means, but I meant each
of the I and Q channels has a bandwidth from 0 to 2.5 MHz.
Steve
Reply by Randy Yates●November 12, 20102010-11-12
spope33@speedymail.org (Steve Pope) writes:
>>if you were designing a decimation filter for a baseband wcdma signal
>>that was oversampled, what target (decimated) bandwidth would you
>>choose?
>
> Somewhere between 2.5 MHz and 4 MHz at baseband?
How could it possibly be 2.5 MHz? The chip rate is 3.84 Mc/s.
--
Randy Yates % "Maybe one day I'll feel her cold embrace,
Digital Signal Labs % and kiss her interface,
mailto://yates@ieee.org % til then, I'll leave her alone."
http://www.digitalsignallabs.com % 'Yours Truly, 2095', *Time*, ELO
Reply by Steve Pope●November 12, 20102010-11-12
>if you were designing a decimation filter for a baseband wcdma signal
>that was oversampled, what target (decimated) bandwidth would you
>choose?
Somewhere between 2.5 MHz and 4 MHz at baseband?
Steve
Reply by Randy Yates●November 12, 20102010-11-12
if you were designing a decimation filter for a baseband wcdma signal
that was oversampled, what target (decimated) bandwidth would you
choose?
--
Randy Yates % "Maybe one day I'll feel her cold embrace,
Digital Signal Labs % and kiss her interface,
mailto://yates@ieee.org % til then, I'll leave her alone."
http://www.digitalsignallabs.com % 'Yours Truly, 2095', *Time*, ELO