The Advanced Demodulator API is a new subsystem of DTAPI v5.2 (part of the February 2013 DekTec SDK release) that contains exciting new functions for receiving and/or monitoring RF modulated signals:
For DVB-T2 and DVB-C2: Demodulation of multiple PLPs simultaneously. Data PLPs can be combined with the corresponding common PLP;
For DVB-T2: Demodulation into a T2-MI stream with all PLPs included in one stream;
Generation of a real-time stream of measurement data: Constellation diagram, impulse response, spectrum, MER and transfer function (absolute value/phase/group delay);
ISDB-T demodulation and extraction of measurements.
To perform its magic, the Advanced Demodulator API uses Software Defined Radio (SDR) technology. Whereas most RF monitoring solutions are essentially based on consumer receiver chips with a set of functions limited by the hardware (and cost considerations), the SDR technology used in DTAPI has no such limitations. Starting from I/Q samples, any desired measurement can be computed and multiple substreams can be demodulated simultaneously. A single Core i7 CPU (or better) is all that is required for executing the SDR routines.
The innovative SDR technology can be used with the DTA-2131 VHF/UHF receiver card for PCIe. The DTA-2131 contains a high-quality VHF/UHF tuner, I/Q demodulator and sample-rate converter, supplying I/Q samples to the SDR routines in the Advanced Demodulator API. The DTA-2135 is also supported, although performance will be significantly lower compared to the DTA-2131.
Basic demodulation requires no extra licenses. The Advanced Demodulator functions require the new RX_ADV license with order code DTC-360-RXA. Reading I/Q samples, e.g. for creating an I/Q sample logger, requires the RX_IQ license (order code DTC-361-IQ). Demodulating T2-MI requires the RX_T2MI license, order code DTC-362-T2MI.
The Advanced Demodulator API uses callback functions to pass demodulated data and measurements from the API to the user application. This way, the application has maximum flexibility in buffering the data and measurements. For further information, please refer to the DTAPI documentation.