Patent ID: 9577651
Date: 2017-02-21
CPC Classifications: H03B,H03L

Claim:
1. A circuit to generate a sweep frequency signal, the circuit comprising: a reference frequency source operative to generate a reference frequency signal; a first frequency combination circuit operating on a first frequency band spanning a range of frequencies, with an input coupled to an output of the reference frequency source, and operative to generate a sweep frequency signal in the first frequency band at its output based on the reference frequency signal; a second frequency combination circuit operating on a second frequency band spanning a range of frequencies that doesn't overlap the range of frequencies of the first frequency band, with an input coupled to the output of the reference frequency source, and operative to generate a sweep frequency signal in the second frequency band at its output based on the reference frequency signal, wherein each of the first frequency combination circuit and the second frequency combination circuit comprises a phase locked loop; a multiple-level switch with an input coupled to an output of the first frequency combination circuit and to an output of the second frequency combination circuit, the multiple-level switch comprising a plurality of switching units connected in series in a switching channel of the multiple-level switch; and a control circuit coupled to and controlling the first frequency combination circuit, the second frequency combination circuit and the multiple-level switch to output (i) the sweep frequency signal at a first frequency in the first frequency band, immediately followed by the sweep frequency signal at a first frequency in the second frequency band, (ii) immediately followed by the sweep frequency signal at a second frequency in the first frequency band, immediately followed by the sweep frequency signal at a second frequency in the second frequency band, and (iii) continuing the pattern of (i) and (ii) to a sweep frequency signal at a Mth frequency in the second frequency band where M is equal to or larger than 3, at an output of the multiple-level switch.