[USRP-users] Re: tx_offset and rx_offset parameter usage on UHD calibration utilities

Hi Rob, Thank you so much for your explanation. It explains the root cause of the issue that I have been experiencing. You are correct that the WBX card I compared with is actually WBX-120, not WBX-40 as I first thought. The WBX-120 don’t have any model name marking on the cards, but when I ran

[USRP-users] Re: tx_offset and rx_offset parameter usage on UHD calibration utilities

On Thu, Jun 12, 2025 at 12:59 AM wrote: > Hi Martin, > > I have been trying to find out whether the lo-offset applies to the first > LO or the second LO as there is no documentation on how it applies to a > specific radio daughter card. From what I have learned, a lo-offset can > apply regardless

[USRP-users] Re: tx_offset and rx_offset parameter usage on UHD calibration utilities

Tom, The issue is that the analog bandwidth of the UBX-40 is only 40 MHz. The LO is always the center of your analog bandwidth. See this diagram. Thus your LO offset is restricted as follows: LO-offset <= (AnalogBW - SignalBW) / 2 In your case your s

[USRP-users] Re: tx_offset and rx_offset parameter usage on UHD calibration utilities

Hi Martin, I have been trying to find out whether the lo-offset applies to the first LO or the second LO as there is no documentation on how it applies to a specific radio daughter card. From what I have learned, a lo-offset can apply regardless of the RF receive frequency is above or below 500

[USRP-users] Re: tx_offset and rx_offset parameter usage on UHD calibration utilities

Hey Tom, I'm still not sure if we're talking about the same thing. Above 500 MHz, one LO is used to mix your signal down to DC. Below 500 MHz, two LOs are used, first to mix up, then to mix down. However, the first LO stage (for < 500 MHz) won't cause IQ imbalance or LO leakage in your signal band

[USRP-users] Re: tx_offset and rx_offset parameter usage on UHD calibration utilities

Hi Marcus, Once again thank you so much for your prompt and detail response. To answer your “direct frequency conversion” question, I like to point out the hardware architecture of UBX-40, the daughter card that we recently switched to because the old model WBX-40 is out of production. I have

[USRP-users] Re: tx_offset and rx_offset parameter usage on UHD calibration utilities

Tommy, I'm either misunderstanding your email, or you're misunderstanding the purpose of the tool, or maybe both. Some facts: - If you're unclear about the arguments, just use the default values, they're probably fine. - These tools are only suitable for direct-conversion (i.e., zero-IF) daughter