Options

 

 

 


 

Options

November 18th, 2018: The Lime options are now shown in the Receive DSP panel instead of the ribbon bar.

The options are:

  • RX Ant: Receive antenna,
  • TX Ant: Transmit anntenna,
  • Vis gain: Visual gain - this value is applied to the data received from the Lime SDR,
  • More: Advanced options (below),
  • RX Calib: Receive calibration,
  • TX Calib: Transmit calibration (radio must be in transmit for calibration to be successful),
  • Gains:
    • Gain: Set the combined gain value in dB. This function computes and sets the optimal gain values of various amplifiers that are present in the device based on desired  gain value in dB. Note actual gain depends on LO frequency and analog LPF configuration, resulting output signal level may be different when those values are changed. When you change this value the LNA, TIA and PGA are updated to reflect the new oeverall gain setting.
    • LNA: Low noise amplifier gain,
    • TIA: Transimpedance amplifier setting,
    • PGA: Programmable-gain amplifier setting.

The icons:

  •   go to the Lime page (the page you're currently viewing).
  •   show the LNA, TIA and PGA settings.
  •  hide the LNA, TIA and PGA settings.

At the bottom you see the chip temperature, TX drive level and TX peak input since the last update (usually one update per second).

 

More (Advanced)

Selecting More opens the advanced options display.

Antennas

The Antennas window shows the frequency range assigned to the antennas by the Lime support library, this information does not reflect any hardware changes.

Calibration

Calibration reduces a spur in the center of the display and strong signal images, both for receive and transmit. It is only possible to calibrate the Lime system once it has been started and running for about one second. Calibration values are restored whenever possible.

Note: calibration is part of the Lime support library. When you press RX Calib / TX Calib and  the receive gain / transmit drive is too low then an error is displayed. When calibration runs automatically any error is suppressed.

Receive

Calibration runs after data has been streaming for the selected number of seconds. You will normally see a small interruption in the waterfall.

Transmit Offset Frequency

To avoid a spur in the center of the transmission bandwidth, offset tuning is supported. A downside of offset tuning is possible 'ghost' carriers if the transmit calibration has not been run.

Monitoring Your Transmission

The only way to reliably monitor your transmission is with another receiver as there is a lot of leakage between the transmit and receive parts of the Lime chip, so what you see on the waterfall while transmitting may not necessarily be the same signal that is sent to the antenna.

 

Clocks

Displays the hardware clocks, enables external reference options.

 

Diagnostics

Optionally save the settings file when the Lime SDR is closed, this is for development use only and will be removed in a future release.

Options

Low-pass Filters

Enable the analog and digital filters, by default these are enabled (recommended).

Lime API Diagnostics

Primarilly for development use, ths enables the level of diagnostic information returned by the Lime support library.

RX Correction

To reduce the spur seen in the centre of the display there are two options: Firmware and Software. The software option is usally better than firmware. Gain and Phase correction are usually enabled.

TX Correction

These options are usually enabled.

TX Other

Disable the transmitter while in receive. Even when not sending and data the transmitter is till active unless disabled, so it is advisable to disable the transmitter while in receive.

Ini files

Used for debelopment / test purposes, specify a .ini file with pre-defined values. These .ini files are usually created with the limeSuite GUI.

 

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