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--- university:tools:pluto:users:non_quad [25 Jul 2019 22:58] – fix Robin Getz
+++ university:tools:pluto:users:non_quad [26 Jul 2019 17:14] – [UHD] Robin Getz
@@ Line 39: / Line 39: @@
 ===== Sending the data =====
-We can send that out the RF, by disabling loopback and setting the Rx and Tx LO to the same value. The results shown during the receiving section are RF loopback (The BIST Loopback setting is set to ''Disable'', and the Rx and Tx SMA connectors are connected via a SMA cable, which is refereed to as "Analog Loopback").
+We can send that out the RF, by disabling loopback and setting the Rx and Tx LO to the same value. The results shown during the receiving section are RF loopback (The BIST Loopback setting is set to ''Disable'', and the Rx and Tx SMA connectors are connected via an SMA cable, which is referred to as "Analog Loopback").
 ====== Receiving a "real" signal ======
@@ Line 50: / Line 50: @@
 | {{:university:tools:pluto:users:rf_lo_same.png?700|}} |
-Its easier to look at this in the time domain. Here the amplitude difference between I & Q is random based on the random difference between the phase of the Rx and Tx PLL. This is indeed completely random, and will change any time either PLL settings are touched. Moving one LO to a different settings, and back again, will change this phase offset (which manifest itself as a magnitude difference between I and Q).
+Its easier to look at this in the time domain. Here the amplitude difference between I & Q is random based on the random difference between the phase of the Rx and Tx PLL. This is indeed completely random and will change any time either PLL settings are touched. Moving one LO to a different setting, and back again, will change this phase offset (which manifest itself as a magnitude difference between I and Q).
 ^  Analog Loopback, Time Domain, I & Q Data, ACG On, Quadrature tracking On   ^
 | {{:university:tools:pluto:users:lo_same_time.png?700|}} |
-You can change this magnitude difference digitally by post processing the sampled data, by using the Phase Rotation control in IIO oscilloscope. It doesn't change the phase relationship between I and Q, but does change the effective sample time relative to the PLL, and therefore changes their relative magnitude. By changing this, you can effectively make either of the I or Q zero, and only receive the signal the other (Q or I), indicating that the received signal is "real" (all information can be received just on one signal channel, and it has no phase or quadrature information.
+You can change this magnitude difference digitally by post-processing the sampled data, by using the Phase Rotation control in IIO oscilloscope. It doesn't change the phase relationship between I and Q, but does change the effective sample time relative to the PLL, and therefore changes their relative magnitude. By changing this, you can effectively make either of the I or Q zero, and only receive the signal the other (Q or I), indicating that the received signal is "real" (all information can be received just on one signal channel, and it has no phase or quadrature information.
 ^  Analog Loopback, Time Domain, I & Q Data  ^
@@ Line 75: / Line 75: @@
 | {{ :university:tools:pluto:users:acg_q_on.png?700 |}} |
-Here the green signal is the ''I'', and the blue is the overall magnitude. Since, during this run, the ''I'' was showing most the the perturbations, and it is small compared to Q, the overall magnitude does not change that much, but it does have undesired step changes, that can be easily fixed when we understand what is happening.
+Here the green signal is the ''I'', and the blue is the overall magnitude. Since, during this run, the ''I'' was showing most the perturbations, and it is small compared to Q, the overall magnitude does not change that much, but it does have undesired step changes, that can be easily fixed when we understand what is happening.
 The first step is to understand that the ACG is reacting to magnitude changes caused by the Quadrature tracking corrections. Turning the ACG to manual mode can help isolate the effects of the IQ Correction. Here is a picture of the same setup with the ACG set to manual mode.
@@ Line 143: / Line 143: @@
 For those using a National Instruments USRP Radio, this can be controlled via ''[[https://files.ettus.com/manual/classuhd_1_1usrp_1_1multi__usrp.html#a586c52db545664cb2caf830ac90c051e|set_rx_iq_balance()]]'' method.
+===== SDRangel =====
+SDRAngel also can turn on/off Quadrature tracking with it's Hardware control buttons.
+{{:university:tools:pluto:users:sdrangel_controls.png?direct|}}
+  * ''RFDC'' : RF DC Correction tracking
+  * ''BBDC'' : BaseBand DC Correction tracking
+  * ''IQ'' : Quadrature tracking
 ===== Scope =====
 This issue will exist on all integrated devices which have some sort of Quadrature tracking feature, including all hardware based on ADI and [[https://github.com/f4exb/sdrangel/issues/378#issuecomment-513012883|other manufactures]]. It's not something specific to the ADALM-PLUTO, or the AD9363.

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