Title:
DETECTION OF MODEM IDENTIFICATION SIGNAL, AND MODEM DEVICE
Document Type and Number:
Japanese Patent JP2522887
Kind Code:
B2
Abstract:
PURPOSE: To detect an S1 sequence by generating four consecutive samples in a specified form by complex index sampling of amplitude of a received base band signal and detecting negative value in a specified calculating result.
CONSTITUTION: Among respective groups consisting of four consecutive samples, the even numbered samples and the odd numbered samples are processed in complex index multiplication units 1, 2. A complex index sampling signal is provided with the form as expressed in an equation I. Respective outputs from the multiplication units 1, 2 are starting points of calculation for the equations I and II to calculate an imaginary parts Vcos.n and Vsin.n. These results are inputted to delay circuit 3 or 4 respectively and time delay of one modulation period is generated before a value of a calculated imaginary number delayed here and the value of the imaginary number at that time are transmitted to a scalar multiplication unit 5 or 6. The results are summed up together in an adder 7 and the output is metric UN expressed in an equation 4. A judging circuit judges whether or not a negative value exists by comparing the Un with zero.
Inventors:
JATSUKU TOOMASU MAAREI
GOTSUTOFURIIDO UNGAABETSUKU
MARUKOMU SUKOTSUTO UEAA
GOTSUTOFURIIDO UNGAABETSUKU
MARUKOMU SUKOTSUTO UEAA
Application Number:
JP21590592A
Publication Date:
August 07, 1996
Filing Date:
August 13, 1992
Export Citation:
Assignee:
INTAANASHONARU BIJINESU MASHIINZU CORP
International Classes:
H04L27/00; H04L27/22; (IPC1-7): H04L27/22; H04L27/00
Domestic Patent References:
| JP55114042A | ||||
| JP6266726A | ||||
| JP62214735A |
Attorney, Agent or Firm:
Koichi Tonmiya (3 outside)