초록 ▼

A programmable apparatus is disclosed for generating a frequency modulated signal all a selected center frequency in accordance with digital data of at least first and second data levels. The modulating apparatus comprises a modulator having an input and an output and is responsive to an input modul

A programmable apparatus is disclosed for generating a frequency modulated signal all a selected center frequency in accordance with digital data of at least first and second data levels. The modulating apparatus comprises a modulator having an input and an output and is responsive to an input modulation signal applied to its input for generating at its output the frequency modulated signal at a center frequency dependent on a quiescent voltage appearing at its input. A circuit is provided for sampling and storing a value of the quiescent voltage, An addressable memory stores a plurality of offsets. A programmable adding circuit adds a downloaded offset voltage to the stored value of the quiescent voltage to output a high modulation voltage. A programmable subtracting circuit subtracts a downloaded offset voltage from the stored value of the quiescent voltage to provide a low modulation voltage. An addressing circuit addresses the memory in accordance with a data transmission parameter for downloading a corresponding offset to the adding and subtracting circuits. A switch or multiplexor is coupled to the subtracting and adding circuits and to receive the digital data for generating and applying to the modulator input an input modulation signal comprising a sequence of the high and low modulation voltages in accordance respectively with the first and second data levels of the digital data.

대표청구항 ▼

Programmable apparatus for generating a frequency modulated signal at a selected center frequency in accordance with digital data of at least first and second data levels, said apparatus comprising: a) a modulator having an input and an output and being responsive to an input modulation signal appli

Programmable apparatus for generating a frequency modulated signal at a selected center frequency in accordance with digital data of at least first and second data levels, said apparatus comprising: a) a modulator having an input and an output and being responsive to an input modulation signal applied to its input for generating at its output the frequency modulated signal at a center frequency dependent on a quiescent voltage appearing at its input; b) means for sampling and storing a value of the quiescent voltage; c) addressable means for storing a plurality of offsets; d) programmable means for adding a downloaded offset voltage to the stored value of the quiescent voltage to output a high modulation voltage; e) programmable means for subtracting a downloaded offset voltage from the stored value of the quiescent voltage to provide a low modulation voltage; f) means for addressing in accordance with a data transmission parameter said addressable storing means and for downloading a corresponding offset to said adding means and said subtracting means; and g) switch means coupled to said subtracting and adding means and to receive the digital data for generating and applying to said input of said modulator the input modulation signal comprising a sequence of the high and low modulation voltages in accordance respectively with the first and second .data levels of the digital data.