PlutoSDR input: updated documentation

plugins/samplesource/plutosdrinput/readme.md

@@ -65,16 +65,7 @@ In baseband sample rate input mode (8A) this is the device to host sample rate i
 
 Use this slider to adjust LO correction in ppm. It can be varied from -20.0 to 20.0 in 0.1 steps and is applied in hardware. This applies to the oscillator that controls both the Rx and Tx frequency therefore it is also changed on the Tx plugin if it is active.
 
-<h3>3-4: Auto correction options</h3>
-
-These buttons control the software DSP auto correction options:
-
-  - **DC**: (6) auto remove DC component
-  - **IQ**: (7) auto make I/Q balance. The DC correction must be enabled for this to be effective.
-
-&#9758; AD9363 has a good hardware DC and I/Q compensation so there should not be a use for this software auto-correction.
-
-<h3>4a: Transverter mode open dialog</h3>
+<h3>3: Transverter mode open dialog</h3>
 
 This button opens a dialog to set the transverter mode frequency translation options:
 
@@ -82,7 +73,7 @@ This button opens a dialog to set the transverter mode frequency translation opt
 
 Note that if you mouse over the button a tooltip appears that displays the translating frequency and if translation is enabled or disabled. When the frequency translation is enabled the button is lit.
 
-<h4>4a.1: Translating frequency</h4>
+<h4>3.1: Translating frequency</h4>
 
 You can set the translating frequency in Hz with this dial. Use the wheels to adjust the sample rate. Left click on a digit sets the cursor position at this digit. Right click on a digit sets all digits on the right to zero. This effectively floors value at the digit position. Wheels are moved with the mousewheel while pointing at the wheel or by selecting the wheel with the left mouse click and using the keyboard arrows. Pressing shift simultaneously moves digit by 5 and pressing control moves it by 2.
 
@@ -96,14 +87,27 @@ For bands even higher in the frequency spectrum the GHz digits are not really si
 
 The Hz precision allows a fine tuning of the transverter LO offset
 
-<h4>4a.2: Translating frequency enable/disable</h4>
+<h4>3.2: Translating frequency enable/disable</h4>
 
 Use this toggle button to activate or deactivate the frequency translation
 
-<h4>4a.3: Confirmation buttons</h4>
+<h4>3.3: Confirmation buttons</h4>
 
 Use these buttons to confirm ("OK") or dismiss ("Cancel") your changes.
 
+<h3>4: Auto correction options</h3>
+
+  - **SW** section: These buttons control the software DSP auto correction options
+    - **DC**: auto remove DC component
+    - **IQ**: auto make I/Q balance. The DC correction must be enabled for this to be effective.
+
+  - **HW** section: These buttons control the hardware AD9363 DC and I/Q compensation
+    - **RFDC**: RF DC correction
+    - **BBDC**: Baseband DC correction
+    - **IQ**: I/Q imbalance correction.
+
+&#9758; There is a reason why you would like to remove any I/Q correction: this is for the reception of signals that are symmetric in I and Q (real signals). More details [here](https://wiki.analog.com/university/tools/pluto/users/non_quad) something not very well known about SDR and DSP.
+
 <h3>5: Software decimation factor</h3>
 
 The I/Q stream from the PlutoSDR is downsampled by a power of two by software inside the plugin before being sent to the passband. Possible values are increasing powers of two: 1 (no decimation), 2, 4, 8, 16, 32, 64.
@@ -123,22 +127,22 @@ With SR as the sample rate before decimation Fc is calculated as:
 
 The AD9363 has many port options however as only the A balanced input is connected you should leave it as the default. This is a provision for people who want to hack the board. The different values may be found in the AD9363 documentation.
 
-<h3>8A: Device to host sample rate / Baseband sample rate input toggle</h3>
+<h3>8: Device to host sample rate / Baseband sample rate input toggle</h3>
 
 Use this toggle button to switch the sample rate input next (8) between device to host sample rate and baseband sample rate input. The button shows the current mode:
 
   - **SR**: device sample rate input mode. The baseband sample rate (1.5) is the device to host sample rate (8) divided by the software decimation factor (5).
   - **BB**: baseband sample rate input mode. The device sample rate (1.5) is the baseband sample rate (8) multiplied by the software decimation factor (5).
 
-<h3>6: Sample rate</h3>
+<h3>9: Sample rate</h3>
 
-This is the device to host sample rate or baseband sample rate in samples per second (S/s). The control (8A) is used to switch between the two input modes.
+This is the device to host sample rate or baseband sample rate in samples per second (S/s). The control (8) is used to switch between the two input modes.
 
 The limits are adjusted automatically. In baseband input mode the limits are driven by the software decimation factor (5). You may need to increase this decimation factor to be able to reach lower values.
 
 Use the wheels to adjust the sample rate. Pressing shift simultaneously moves digit by 5 and pressing control moves it by 2. Left click on a digit sets the cursor position at this digit. Right click on a digit sets all digits on the right to zero. This effectively floors value at the digit position. Wheels are moved with the mousewheel while pointing at the wheel or by selecting the wheel with the left mouse click and using the keyboard arrows.
 
-The minimum sample rate depends on the hardware FIR decimation factor (12) and is the following:
+The minimum sample rate depends on the hardware FIR decimation factor (13) and is the following:
 
   - no decimation: 25/12 MS/s thus 2083336 S/s (next multiple of 4)
   - decimation by 2: 25/24 MS/s thus 1041668 S/s
@@ -146,17 +150,17 @@ The minimum sample rate depends on the hardware FIR decimation factor (12) and i
 
 The maximum sample rate is fixed and set to 20 MS/s
 
-<h3>9: Rx analog filter bandwidth</h3>
+<h3>10: Rx analog filter bandwidth</h3>
 
 This is the Rx analog filter bandwidth in kHz in the AD9363 device. It can be varied from 200 kHz to 14 MHz in 1 kHz steps. Use the wheels to adjust the value. Pressing shift simultaneously moves digit by 5 and pressing control moves it by 2.
 
-<h3>10: Hardware FIR filter toggle</h3>
+<h3>11: Hardware FIR filter toggle</h3>
 
 The AD9363 chip has an optional FIR filter in the Rx decimation chain as the last decimation block. Use this button to activate or deactivate the filter.
 
 The FIR filter settings are the same on Rx and Tx side therefore any change here is automatically forwarded to the Tx GUI.
 
-<h3>11: Hardware FIR filter bandwidth</h3>
+<h3>12: Hardware FIR filter bandwidth</h3>
 
 Use the wheels to adjust the bandwidth of the hardware FIR filter. Pressing shift simultaneously moves digit by 5 and pressing control moves it by 2.
 
@@ -166,15 +170,15 @@ For bandwidths greater than 0.2 times the FIR filter input frequency the filter
 
 For bandwidths between 0.05 and 0.2 times the FIR filter input frequency the window used is a Hamming window giving a sharper transition.
 
-<h3>12: Hardware FIR decimation factor</h3>
+<h3>13: Hardware FIR decimation factor</h3>
 
 The FIR filter block can provide a decimation by 1 (no decimation), 2 or 4. This controls the minimum possible baseband sample rate as already discussed in (8).
 
-<h3>13: Hardware FIR gain</h3>
+<h3>14: Hardware FIR gain</h3>
 
 The FIR filter can introduce a gain that can be set to -12, -6, 0 or 6 dB. The FIR has a fixed gain of 6 dB so to maximize dynamic range one would set the gain at -6 dB so that the overall gain is set at 0 dB.
 
-<h4>14: Gain mode</h2>
+<h3>15: Gain mode</h3>
 
 Use this combo to select between gain options:
 
@@ -185,18 +189,18 @@ Use this combo to select between gain options:
 
 See AD9363 documentation for details on AGC options.
 
-<h4>15: Global manual gain</h4>
+<h3>16: Global manual gain</h3>
 
-Use this button to adjust the global gain manually in manual gain mode. This button is disabled when AGC modes are selected with combo (14).
+Use this button to adjust the global gain manually in manual gain mode. This button is disabled when AGC modes are selected with combo (15).
 
-<h4>15a: Actual gain fetched from device</h4>
+<h3>17: Actual gain fetched from device</h3>
 
 This is the actual gain in dB set in the device.
 
-<h4>16: Indicative RSSI</h4>
+<h3>18: Indicative RSSI</h3>
 
 This is the indicative RSSI of the receiver.
 
-<h3>17: Board temperature</h3>
+<h3>19: Board temperature</h3>
 
 This is the board temperature in degrees Celsius updated every ~5s.