How to use Audio DSP on Antenna Analyzer (Features included after CEC V0.5)
Audio DSP is a function that filters the sound coming from the transceiver into a desired range.
You do not need any hardware changes to use this feature. Just prepare your headphones. If you want to make a little bit better, you can add a very small $ 1 speaker to your board.
I am preparing to distribute the test firmware (V0.52). Please wait 1 ~ 2 days.
EU1KY AA and Headphone.
The STM32F746 board has two sound inputs. However, Mic Jack is already using the EU1KY RF board.
Another sound input method of the STM32F746 is two microphones mounted on the board.
I use only one of the two microphones. (Right)
Put AA near the transceiver speaker and plug your headphone into the phone jack and you're all set.
Or you can install a small speaker as shown below.
You could easily get a small speaker around you. It can be extracted from malfunctioning headphone, earphone, mobile phone.
The speakers I used are below.
2.How to use
Below is a picture of my development board. I put a very small speaker on Mic for testing.
On the main screen, touch 'Audo DSP' button.
If you turn on your transceiver, you will probably see fft spectrum and waterfall graphs as shown below.
In the first run, it operates in 'Pass Through' mode.
May be too loud, so make sure the volume of the transceiver is very small in 'Pass through' mode.
Touch the desired filter button.
If you are filtering a fairly narrow area, please select BPF.
BPF supports 50Hz, 100Hz and 150Hz filtering.
Continue to touch the BPF button to change the filtering bandwidth.
Touch the red squares (B) below to move the center frequency.
The yellow squares(A) is the area to adjust the bandwidth in User Filter mode.
Move the center frequency to the area you want to hear.
If you hear a small noise when moving to the area you want to hear, increase the volume of the transceiver.
Since most of the other areas are removed, if you raise the volume, you will hear what you want to qso. Volume control is important.
If you have selected User Filter, you can select the range you want to hear by dragging the L and R areas below.
Since the center frequency is maintained even if you touch the BPF and the User filter alternately, it can be used alternately according to the communication status.
Please refer to the video below for an example of use.
Thank you for reading