Patent ID: 8085107

Claim:
A transmission module for transmitting digital signals by modulation of a carrier, determined by the digital signals, by means of two-step or multi-step frequency shift keying, the transmission module including: a PLL circuit having a voltage-controlled oscillator, and a controllable frequency divider with a frequency divider control input, wherein the transmission module is configured to induce a direct frequency shift keying (DFSK) of the carrier signal by appropriate triggering of the frequency divider with at least two different frequency divider control signals, wherein the transmission module includes a modulation data preprocessing unit connected to the frequency divider control input, the modulation data preprocessing unit being configured to weight samples of the same polarity of the digital signals to be transmitted and to fine tune the frequency divider control signal with regard to the frequency deviation to be induced, wherein the PLL circuit has a signal output for output of a modulated output signal and is connected to a calibrator circuit, the calibrator circuit being configured to derive weightings for samples of a respective digital signal to be transmitted as well as correction values for the respective frequency divider control signal from a respective modulated output signal, wherein the calibrator circuit has a test receiver, which is configured as an unmodulated fractional-N synthesizer with an open control loop.