ESP32 SDR Frequency Calculator

The ESP32's built-in ADC can directly sample signals up to roughly 6 MHz, but practical SDR use is limited by the ADC sample rate and I2S clock. With external mixers or undersampling, higher frequencies can be received, but the calculator shows the safe direct-sampling range based on your parameters.

According to the Nyquist theorem, the maximum representable bandwidth is half the ADC sample rate. For example, a 2 MSPS sample rate gives a theoretical 1 MHz bandwidth, but real-world filters and processing reduce this. The calculator applies practical limits and shows the actual usable bandwidth.

The actual sample rate depends on the I2S clock and ADC bit depth. The ESP32 I2S peripheral divides the clock, so the requested sample rate may not be exactly achievable. The calculator computes the closest achievable rate and warns if it deviates significantly.

Yes. The calculator includes parameters for ESP32, ESP32-S3, and ESP32-C3. Each model has different ADC and I2S capabilities, and the tool adjusts the frequency range and bandwidth limits accordingly.

It suggests optimal ADC attenuation, I2S clock settings, and anti-aliasing filter requirements. It also flags if your target frequency or bandwidth exceeds the hardware limits and recommends undersampling or external mixing if needed.