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Re: [Discuss-gnuradio] Question regarding the DBSRX frequency range and
From: |
Matt Ettus |
Subject: |
Re: [Discuss-gnuradio] Question regarding the DBSRX frequency range and bandwidth |
Date: |
Wed, 27 Jun 2007 18:53:03 -0700 |
User-agent: |
Thunderbird 2.0.0.0 (X11/20070326) |
Eric A. Cottrell wrote:
> Matt Ettus wrote:
>
>> Bandwidth:
>> When Maxim states that their maximum LPF bandwidth is 33 MHz, they
>> mean one-sided bandwidth (i.e. 0 to 33 MHz). Since it is used in a
>> direct conversion IQ system, that actually gives a 66 MHz bandwidth (-33
>> MHz to +33 MHz). Since that is beyond nyquist for our ADC, I spec to 60
>> MHz (+/- 30 MHz).
>>
>> On the low end, they specify 4 MHz, which is really 8 MHz (+/-4 MHz)
>> of RF bandwidth. The filter is actually capable of going to a much
>> narrow frequency, but it is outside of Maxim's specs, since nobody in
>> the small satellite dish market cares about less than 8 MHz of BW. So I
>> spec that it goes down to 1 MHz wide. It should be noted that when you
>> go below 4 MHz wide (2 MHz in Maxim-speak) that your noise floor will
>> rise a bit and phase noise may also rise.
>>
>> Matt
>>
> Hello,
>
> I assume the parameter for the setbw function is the double-sided
> bandwidth and not Maxim-speak?
>
Actually, it is in Maxim-speak... Should probably be changed.
Matt