Patent ID: 7365608

Claim:
A digital frequency synthesiser for producing a frequency swept synthesised output signal, the digital frequency synthesiser being implemented on a single chip, and comprising: an on-chip direct digital frequency synthesiser for producing the synthesised output signal of frequency directly responsive to a frequency control digital word applied thereto, an on-chip data storing circuit for storing data defining a frequency sweep of the frequency swept synthesised output signal in the frequency domain and in the time domain, a single pin control terminal adapted for receiving an externally generated logic control signal, an on-chip data processing circuit for determining from the frequency domain data stored in the data storing circuit respective values of the frequency control digital word and the sequence thereof in which the values of the frequency control digital word are to be applied to the direct digital frequency synthesiser for producing the frequency swept synthesised output signal, the data processing circuit being responsive to one of the data stored in the data storing circuit defining the time domain of the frequency sweep, a logic control signal applied to the control terminal, and a combination of a logic control signal applied to the control terminal and data stored in the data storing circuit defining the time domain of the frequency sweep for determining the rate at which the values of the frequency control digital word are to be applied to the direct digital frequency synthesiser and for applying the values of the frequency control digital word in the sequence and at the determined rate to the direct digital frequency synthesiser for producing the frequency swept synthesised output signal.