Hi, I have some open questions about tx_offset and rx_offset parameter usage for the UHD calibration utility uhd_cal_rx_iq_balance, uhd_cal_tx_iq_balance, and uhd_cal_tx_dc_offset.
The cal util -help output indicates tx_offset is the TX LO offset from the RL LO in Hz. Likewise, for the rx_offset. If the usrp app uses a direct frequency conversion and no LO is involved, then tx_offset is zero. One strange thing is that when the parameter is not specified, the cal util will use a default value 934400 internally. I don't know where this constant came from. Does it mean for direct frequency conversion, I should specify tx_offset of 0 (to override the default 934400) when performing a calibration? My application runs on X310 with 2 UBX-40 installed for duplex operation. It does specify a Rx LO on the receive and a Tx LO on the transmit, but the difference between the Tx LO and Rx LO is 40MHz, which exceeds the tx_offset/rx_offset max limit of 20MHz. Therefore, my only option is to run the calibration without tx_offset and rx_offset specified, but I wonder how the calibration result would impact my application performance. I appreciate it if anyone can share his/her experience on the UHD cal utility rx_offset & tx_offset usage. Thanks, Tom ________________________________ The information contained in this e-mail and any attachments from W5 Technologies, Inc. may contain confidential and/or proprietary information, and is intended only for the named recipient to whom it was originally addressed. If you are not the intended recipient, any disclosure, distribution, or copying of this e-mail or its attachments is strictly prohibited. If you have received this e-mail in error, please notify the sender immediately by return e-mail and permanently delete the e-mail and any attachments.
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