Title:
デジタル送信用AM送信機においてスプリアス発射を回避する方法
Document Type and Number:
Japanese Patent JP4209321
Kind Code:
B2
Abstract:
A method for avoiding spurious emissions in an AM transmitter for digital transmission includes converting a digital modulation for controlling the AM transmitter into an amplitude signal for an amplitude branch, and a phase-modulated RF signal for a RF branch. Non-linear distortions in an amplitude response and a delay-time characteristic of an amplitude branch are compensated for using a pre-equalization with inverse shapes by measuring and storing the amplitude response and the delay-time characteristic of the RF branch. An inverse transfer function is determined using respective shapes of the measured amplitude response and delay-time characteristic by an inverse Fourier transform. An equalizing network is dimensioned for the determined inverse transfer function. The equalizing network is connected in series upstream of the RF branch. The amplitude and RF branches are combined downstream of the amplitude and RF branches.
Inventors:
Rudolf, Dietmar
Application Number:
JP2003509734A
Publication Date:
January 14, 2009
Filing Date:
April 10, 2002
Export Citation:
Assignee:
Deutsche Telecom AG
International Classes:
H04B1/04; H04L27/18; H03F1/32; H04H20/00
Domestic Patent References:
| JP2180453A | ||||
| JP2002530992A | ||||
| JP2000078037A | ||||
| JP11308142A | ||||
| JP2000349734A |
Attorney, Agent or Firm:
Masao Okabe
Nobuaki Kato
Kazuo
Shinichi Usui
Ikuo Fujino
Takao Ochi
Teruhisa Motomiya
Norimichi Takanashi
Asahi Shinmitsu
Seiichiro Takahashi
Koji Yoshizawa
Nobuaki Kato
Kazuo
Shinichi Usui
Ikuo Fujino
Takao Ochi
Teruhisa Motomiya
Norimichi Takanashi
Asahi Shinmitsu
Seiichiro Takahashi
Koji Yoshizawa