The following timing diagram (that I draw with Wavedrom, a fantastic tool for that purpose) shows in the upper part the output format of the ADC3660 as I understand it from the datasheet: The signal in the middle („NSS_TI“) shows the NSS signal as it Read More …
Schlagwort: SDR
How to connect an ADC3660 to an MCU (part I)
TI’s new family of SAR-ADCs with integrated DDCs could be a game changer for building SDRs for HAM radio operators. Why? Because these ADCs do not only contain an NCO and a complex digital IQ downmixer, they also integrate a decimation stage and an output Read More …
Improved Reception of Radio DARC; preamp unnecessary
CIC compensation filters now follow the 2-stage decimating CIC filters for the I-Q-signals. The CIC compensation filters are two identical FIR filters (one filter each for the I signal and an identical filter for the Q signal) with currently 81 taps. They flatten the passbands Read More …
The DFSDM of the STM32H7 or 128 != 16×8 != 8×16 (Part III)
continued from part II: The passband of CIC filters is not flat. This begs the question of whether this behavior should be corrected. In most cases, the CIC is therefore followed by a so-called CIC compensation filter. Zooming into the filter plot of the sinc4/dec.15 Read More …
The DFSDM of the STM32H7 or 128 != 16×8 != 8×16 (Part II)
continued from part I: As explained in part I, the first version of my H7-SDR uses only one CIC filter of the DSFDM for filtering the I-signal and another one for filtering the Q-signal. However, the DSFDM contains 4 filters (see chapter 30 of RM0433 Read More …
The DFSDM of the STM32H7 or 128 != 16×8 != 8×16 (Part I)
My software defined radio for receiving AM transmissions in the 49 m band (see https://dm1cr.de/reception-of-radio-darc-transmission-with-a-microcontroller-only-sdr) looks quite primitive in the first version: It comprises a bandpass filter for anti-aliasing, an STM32H743ZI microcontroller and an audio amplifier with loudspeaker. The ADC inside of the STM32H7 is Read More …
Reception of a Radio-DARC-transmission with a microcontroller-only-SDR
A few moments ago I was able to receive the Radio-DARC-transmission from 11:00 CEST, Sunday, June 13, 2021, with my homebuilt SDR, that just became ready for a first try on the antenna. The received sound was loud and clear. The SDR comprises an anti-aliasing-filter, Read More …
Bandpass sampling and analog bandwidth of the 16-bit ADC peripheral of the STM32H7, Part I
I have to admit of having had some prejudices about ADCs in microcontrollers.From my experience, they are slow and noisy of no use for really demanding applications.Well, the 16-bit ADC peripheral of the STM32H7 of ST Microelectronics may be a real game-changer. It seems to Read More …