Carrier changer and changing method

• US 6,778,590 B1
• Filed: 06/28/2000
• Issued: 08/17/2004
• Est. Priority Date: 06/29/1999
• Status: Active Grant

• Current Assignee: SK Telecom Co., Ltd.
• Original Assignee: SK Telecom Co., Ltd.
• Inventors: Kim, Jong Ok, Lee, Tae Hyung, Choi, In Sung, Lee, Duk Ju
• Primary Examiner(s): Bayard, Emmanuel
• Assistant Examiner(s): Nguyen, Dung X.
• Application Number:
  US09/606,416
• Time in Patent Office: 1,511 Days
• Field of Search: 375/135, 375/145, 375/149, 375/295, 375/259, 375/260, 375/297, 370/335, 370/342, 455/91, 455/103
• US Class Current: 375/145
• CPC Class Codes: H03D 7/00 Transference of modulation from one carrier to another, e.g. frequency-changing H03D9/00, H03D11/00 take precedence; dielectric amplifiers, magnetic amplifiers, parametric amplifiers used as a frequency-changers H03F

Abstract

A carrier changer and changing method capable of generating a plurality of pseudo carriers by one pseudo carrier generator is provided. In the carrier changer, a pseudo carrier generator selectively generates one of a plurality of forward pseudo carrier signals based on a forward signal by a time division. A forward signal processor receives the forward signal and generates a pseudo carrier generating signal based on the forward signal, and outputs the forward signal and the pseudo carrier signals generated by the pseudo carrier generator. A power amplifier amplifies powers of the forward signal and pseudo carrier signals from the forward signal processor. Since an output of a phase locked loop is generated according to a variable phase locked loop data, pseudo carrier signals having different frequencies can be obtained by one pseudo carrier generator. Since one power amplifier a plurality of pseudo carries signals, additional amplifiers need not being used. Since a plurality of pseudo carrier signals are generated by a time division, insertion loss due to usage of a divider and synthesizer is not generated.

Claims

1. A carrier changer comprising:

a pseudo carrier generator for selectively generating one of a plurality of forward pseudo carrier signals based on a forward signal by a time division;

a forward signal processor for receiving the forward signal and generating a pseudo carrier generating signal based on the forward signal, and outputting the forward signal and the plurality of forward pseudo carrier signals generated by the pseudo carrier generator; and

a power amplifier for amplifying powers of the forward signal and pseudo carrier signals from the forward signal processor, wherein the pseudo carrier generator includes

a first band pass filter for band pass filtering the pseudo carrier generating signal at a first predetermined bandwidth;

a first amplifier for amplifying an output signal of the first band pass filter;

an intermediate frequency generator for converting an output signal of the first amplifier into an intermediate frequency signal;

an intermediate frequency amplifier for amplifying the intermediate frequency signal from the intermediate frequency generator according to a gain of the pseudo carrier generating signal;

a frequency converter for generating one of the forward pseudo carrier signals based on an output signal of the intermediate frequency amplifier according to a variable phase locked loop frequency data;

a second amplifier for amplifying the one of the forward pseudo carrier signal from the frequency converter; and

a second band pass filter for band pass filtering an output signal of the second amplifier at a second predetermined bandwidth.

2. The carrier changer as defined in claim 1, wherein the intermediate frequency generator includes

a phase locked loop for receiving a phase locked loop frequency data and generating a phase locked loop output signal based on the phase locked loop frequency data in response to a system clock; and

a mixer for mixing an output signal of the first amplifier and the phase locked loop output signal from the phase locked loop.

3. The carrier changer as defined in claim 1, wherein the frequency converter includes

a first phase locked loop for receiving the variable phase locked loop frequency data and generating a first pseudo carrier generating output signal based on the variable phase locked loop frequency data in response to a system clock;

a first frequency stabilizing selector for removing a transition part included in the first pseudo carrier generating output signal from the first phase locked loop by a time switching;

a third band pass filter for band pass filtering an output signal of the first frequency stabilizing selector at a third predetermined bandwidth; and

a first mixer for mixing the output signal of the intermediate frequency amplifier and an output signal of the third band pass filter.

4. The carrier changer as defined in claim 3, the frequency converter further includes a control section for generating a masking signal for removing the transition part included in the first pseudo carrier generating out signal from the first phase locked loop.

5. The carrier changer as defined in claim 1, wherein the frequency converter includes

a second phase locked loop for receiving the variable phase locked loop frequency data and generating a second pseudo carrier generating output signal based on the variable phase locked loop frequency data in response to a system clock;

a fourth band pass filter for band pass filtering the second pseudo carrier generating output signal from the second phase locked loop at a fourth predetermined bandwidth;

a second mixer for mixing the output signal of the intermediate frequency amplifier and an output signal of the fourth band pass filter; and

a second frequency stabilizing selector for removing a transition part included in the pseudo frequency signal from the second mixer by a time switching.

6. The carrier changer as defined in claim 2, wherein the frequency converter includes

a third phase locked loop for receiving the variable phase locked loop frequency data and generating a pseudo carrier generating output signal based on the variable phase locked loop frequency data in response to a system clock;

a second frequency stabilizing selector for removing a transition part included in the pseudo carrier generating output signal from the third phase locked loop by a time switching;

a fifth band pass filter for band pass filtering an output signal of the second frequency stabilizing selector at a fifth predetermined bandwidth; and

a third mixer for mixing the output signal of the intermediate frequency amplifier and an output signal of the fifth band pass filter in order to generate a pseudo frequency signal; and

a third frequency stabilizing selector for removing spurious included in the pseudo frequency signal from the third mixer by a time switching.

7. The frequency changer as defined in claim 1, wherein

the forward signal processor includes a first directional coupler for receiving and outputting the forward signal, and generating the pseudo carrier generating signal based on the forward signal by a loose coupling;

a circulator for preventing the forward signal from the first directional coupler from outputting in a reverse direction; and

a second directional coupler for outputting the forward pseudo carrier signal from the pseudo carrier generator and an output signal of the circulator by a loose coupling.