US 7,557,668 B2
Injection-locked frequency divider
Sheng-Lyang Jang, Taipei (Taiwan); Yun-Hsueh Chuang, Taoyuan County (Japan); Ren-Hong Yen, Taipei (Taiwan); and Shao-Hwa Lee, Taipei County (Taiwan)
Assigned to National Taiwan University of Science and Technology, Taipei (Taiwan)
Filed on Nov. 19, 2006, as Appl. No. 11/561,417.
Claims priority of application No. 95135751 A (TW), filed on Sep. 27, 2006.
Prior Publication US 2008/0074199 A1, Mar. 27, 2008
Int. Cl. H03B 5/081 (2006.01)
U.S. Cl. 331—167  [331/117 R; 331/117 FE; 331/177 V] 35 Claims
OG exemplary drawing
 
1. An injection-locked frequency divider, suitable for performing a frequency division action on an injection signal to generate a frequency division signal, comprising:
a variable reactance unit, having a first connecting terminal and a second connecting terminal, for adjusting a reactance value of the injection-locked frequency divider and outputting the frequency division signal through the first connecting terminal and the second connecting terminal;
a signal injection unit, coupled to the first connecting terminal and the second connecting terminal, for receiving the injection signal;
a first switch, with a first terminal coupled to the first connecting terminal and a control terminal coupled to the second connecting terminal;
a second switch, with a first terminal coupled to the second connecting terminal and a control terminal coupled to the first connecting terminal;
a first transformer, having a primary-side coil and a secondary-side coil, the primary-side coil of the first transformer being coupled between the first connecting terminal and a ground terminal, and the secondary-side coil of the first transformer being coupled between the second terminal of the first switch and an operating voltage; and
a second transformer, having a primary-side coil and a secondary-side coil, the primary-side coil of the second transformer being coupled between the second connecting terminal and the ground terminal, and the secondary-side coil of the second transformer being coupled between the second terminal of the second switch and the operating voltage.