DH1AKF
FM (88-108 MHz), 90.1 Mhz?
DH1AKF
FM (88-108 MHz), 90.1 Mhz?
. . Teensy 3.6 . ESP32-LyraT. , . . .
, FM ...
Specifications at the moment:
EDITED 2017_05_03 for new features:
* Teensy 3.6 with audio board working in floating point
* reception from about 12kHz to 30Mhz (in undersampling
mode 50MHz to 151MHz)
* decimation-by-8
* FFT and inverse FFT with 1024 points using the new
CMSIS DSP lib complex FFT function
* filtering with 513 tap FIR filter (in decimated 12ksps) -->
comparably steep filters are normally available in
commercial receivers from 2000$ upwards
* filter coefficients are calculated by the Teensy itself and
the filter bandwidth can be chosen arbitrarily by the user
* demodulation of real synchronous AM with selectable
sideband and "stereo" option, 9 "different" AM
demodulators, LSB, USB, pseudo-Stereo-USB, pseuso-
Stereo-LSB (maybe more to come . . .)
* demodulation of wideband FM Stereo transmissions
* display up to 192kHz of frequency spectrum
* Zoom into the spectrum for greater frequency resolution
detail: Zoom FFT enables us to have up to 10Hz resolution
in the spectrum display
* superb audio quality
* needs about 46% of the processor ressources at 96ksps
sample rate and SAM demodulation, about 48% at
192ksps and AM demodulation, SAM at 192ksps needs
78% because of the atan2f calculations
* autotune on demand --> press a button and the carrier
of an AM station is caught with an accuracy < 1Hz
* automatic gain control AGC borrowed from the excellent
wdsp library by Warren Pratt
* dynamic frequency graticules on the x-axis of the
spectrum display
* S-meter
* display of signal strength in dBm or dBm/Hz
* small frequency display showing the SAM carrier
frequency
* real time clock working and on display
* optional manual IQ amplitude and phase imbalance
correction
* automatic IQ amplitude and phase imbalance correction
to account for imbalances in your hardware IQ production
* menu system to adjust many parameters
* save and load settings to/from EEPROM
* play MP3 or AAC files in Hifi stereo quality from the SD
card
* reception of wideband FM broadcast stations by 1/5
undersampling with the same hardware --> MONO, but
HiFi quality when using 192ksps sample rate
* automatic test for the "twinpeak syndrome" - a fault in
the mirror rejection that occurs sometimes at startup. This
is now reliably detected by the automatic IQ phase
correction algorithm and the codec restarted to cure the
problem
* AGC now has an optical indicator for the AGC threshold
and many more AGC parameters can be adjusted
* Codec gain has now its own automatic AGC
* Spectrum display now also has an "AGC" that prevents
empty screen for small signals
* manual notch filter with adjustable notch frequency and
notch bandwidth
sgk; 15.02.2019 10:27. :
-
http://www.cqham.ru/forum/attachment...9&d=1549978669
DH1AKF, 12 1.5?
, .us5evd
, 150 . 12 , .
DH1AKF
, Teensy 3.6 .
( .)
?
SVd2004
, . , . . , PSoC6.
:
- ,
- C-.
DH1AKF
?
ADC_REF >
PHASE Q >
PHASE I >
QSD Audio- Shield: (Line In)
Phase-I Left
Phase-Q Right
GND G
ADC-Ref not connected
output: Line out (L, R, Ground)
: 1 (: 0 , : 1)
