- Magenta (or pink) square icon: an error occurred. In the case the device was accidentally disconnected you may click on the icon, plug back in and start again.
If you have the Rx open in another tab and it is running then it will be stopped automatically before the Tx starts. In a similar manner the Tx will be stopped before the Rx is started from the Rx tab.
In host to device sample rate input mode (8A) this is the baseband I/Q sample rate in kS/s. This is the host to device sample rate (8) divided by the interpolation factor (10).
In baseband sample rate input mode (8A) this is the host to device sample rate in kS/s. This is the baseband sample rate (8) multiplied by the software interpolation factor (10)
Transmission latency depends essentially in the delay in the sample FIFO. The size of sample FIFO is calculated to give a fixed delay of 250 ms or 150000 samples whichever is bigger. Below is the delay in seconds vs baseband sample rate in kS/s from 48 to 800 kS/s. The 250 ms delay is reached at 600 kS/s:
Use this toggle button to switch the sample rate input next (8) between host to device sample rate and baseband sample rate input. The button shows the current mode:
- **SR**: host to device sample rate input mode. The baseband sample rate (2) is the host to device sample rate (8) divided by the interpolation factor (10).
- **BB**: baseband sample rate input mode. The host to device sample rate (2) is the baseband sample rate (8) multiplied by the interpolation factor (10).
<h3>8: Sample rate</h3>
This is the HackRF device DAC sample rate or baseband sample rate in samples per second (S/s). The control (8A) is used to switch between the two input modes. The device to/from host stream sample rate is the same for the Rx and Tx systems.
The limits are adjusted automatically. In baseband input mode the limits are driven by the interpolation factor (10). You may need to increase this interpolation factor to be able to reach lower values.
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.
The baseband stream is interpolated by this value before being sent to the HackRF device. Possible values are:
- **1**: no interpolation
- **2**: multiply baseband stream sample rate by 2
- **4**: multiply baseband stream sample rate by 4
- **8**: multiply baseband stream sample rate by 8
- **16**: multiply baseband stream sample rate by 16
- **32**: multiply baseband stream sample rate by 32
- **64**: multiply baseband stream sample rate by 64
The main samples buffer is based on the baseband sample rate and will introduce ~500ms delay for interpolation by 16 or lower and ~1s for interpolation by 32.
When a device set for the same physical device is present the device center frequencies are synchronized because there is only one LO for the physical device.
When the center frequency position Fc (control 9) is set to center (Cen) in both Tx and Rx the actual frequency of reception and transmission are the same.
In other cases for both frequencies to match you have to set the same sample rate and Fc position (either Inf or Sup) in the Tx and Rx.
