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Re: [Discuss-gnuradio] improper WBX transmission of tone in center of sp
From: |
George Nychis |
Subject: |
Re: [Discuss-gnuradio] improper WBX transmission of tone in center of spectrum |
Date: |
Wed, 4 Aug 2010 21:17:45 -0700 |
Thanks for the help, Matt. I never actually knew what DC offset was until now ;) Learning as I go!
From what I understand, the USRP2 scales between -1.0 and 1.0. I am trying to boost my transmit power well over the power of the DC offset. I think that if I increase the gain, the DC offset is also boosted. So I am trying to boost my signal over it (for this 75dB separation). I am scaling my samples to the -1 and 1 range, but I am not seeing that much separation after scaling:
That's about a 5dB separation after scaling. I am not adding any attenuation, and this is conducted. I am also configuring the gain to 0, so as to not boost the DC offset either.
Thanks for the help, I appreciate it.
- George
On Wed, Aug 4, 2010 at 2:59 AM, Bob McGwier
<address@hidden> wrote:
That is an awesome amount of LO suppression in an SSB mixer based system (I mean the power 1/330000-th of the LO). A more interesting number given this level of LO suppression would be the introduction of a tone (say) above the LO at LO+F and to see what the power is at LO-F (the image).
Bob
On 8/3/2010 4:55 PM, Matt Ettus wrote:
The WBX can put out about 20dBm at 520 MHz. -55dBm would be 75dB below
the desired signal, which is quite a good amount of LO suppression. If
you need more, you'll need to actively calibrate the DC offset to null
it out.
Matt
On 08/03/2010 12:55 PM, George Nychis wrote:
The power of the tone comes in to the spectrum analyzer at -55.6dBm
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