21.1 Overview

The AT86RF212B offers a Continuous Transmission Test Mode to support application and production tests as well as certification tests. Using this test mode, the radio transceiver transmits continuously a previously transferred frame (PRBS mode) or a continuous wave signal (CW mode).

The AT86RF212B uses I/Q modulation for both, PRBS mode and CW mode. In CW mode, this results in a signal which is not placed at the selected channel center frequency FC, but at 0.1 or 0.25MHz apart this frequency. One out of four different signal frequencies per channel can be transmitted:

  • f1 = FC + 0.25MHz using O-QPSK 1000kb/s mode
  • f2 = FC - 0.25MHz using O-QPSK 1000kb/s mode
  • f3 = FC + 0.1MHz using O-QPSK 400kb/s mode
  • f4 = FC - 0.1MHz using O-QPSK 400kb/s mode

As a side effect of I/Q modulation, CW mode shows some unwanted signal components based on finite image rejection and non-linearities.

In addition to the above mentioned modes – a CW mode which directly uses the PLL signal without I/Q modulation. This is the recommended mode because the signal is placed at the selected channel center frequency FC and unwanted signal components are significantly lower.

PRBS mode requires data in the frame buffer, that is a valid PHR followed by PSDU data. After transmission of two non-PSDU octets, PSDU data is repeated continuously.