Title:
変調用半導体集積回路
Document Type and Number:
Japanese Patent JP3972091
Kind Code:
B2
Abstract:
The present invention is directed to reduce fluctuations in modulation frequency of a VCO caused by a temperature change in a semiconductor integrated circuit for use in a radio communication system of a frequency hopping method performing modulation by controlling the VCO of an LC oscillation type in accordance with transmission data in an open loop by using the VCO. In a semiconductor integrated circuit of a frequency hopping method performing modulation by directly controlling an LC oscillation type VCO on the basis of transmission data and transmitting data while switching a carrier frequency, a temperature characteristic correcting circuit is provided which give a negative temperature characteristic to a reference current value of a circuit (such as a DA converter) for generating a control voltage of the VCO so that a modulation-side control input voltage having a positive temperature characteristic and controlling the VCO comes to have a negative temperature characteristic.
Inventors:
Hirokazu Miyakawa
Katsumi Yamamoto
Tatsuji Matsuura
Katsumi Osaki
Katsumi Yamamoto
Tatsuji Matsuura
Katsumi Osaki
Application Number:
JP2001320677A
Publication Date:
September 05, 2007
Filing Date:
October 18, 2001
Export Citation:
Assignee:
Renesas Technology Corp.
International Classes:
H03C3/00; H03L1/02; H03C3/09; H03L7/099
Domestic Patent References:
| JP4061415A | ||||
| JP3236634A | ||||
| JP9083252A | ||||
| JP7007326A | ||||
| JP57074516U |
Attorney, Agent or Firm:
Shizuyo Tamamura