Signal generator
 Apparatus is described for generating a frequency-sweepable measurement signal and a local signal with a frequency separated from the measurement signal frequency by an intermediate frequency. The measurement signal and a local signal are generated by a simple structure, including a high-frequency variable-frequency signal source, a low-frequency fixed-frequency signal source, a first frequency divider and a second frequency divider. The variable-frequency signal source is a sweepable signal source. The first frequency divider divides an output frequency fa from the variable-frequency signal source by n and outputs a measurement signal with a frequency of fa/n. The signal of the variable-frequency signal source is also applied to the first input of the second frequency divider, and the signal of fixed-frequency signal source, with a frequency of fb, is applied to the second input. The second frequency divider removes a one period signal from the signal of the variable-frequency signal source each period of the signal of fixed-frequency signal source, thus obtaining a signal with a frequency of fa-fb. This latter signal is divided by n and a signal with a frequency of (fa-fb)/n is output as the local frequency. fb/n is the intermediate frequency. 
Hewlett-Packard Company
H G H
H03B G01R H03B
inventional inventional inventional
Hideki Kazuyuki
Yamashita Yagi