Echo preventing circuit and digital signal processing circuit

Details Echo preventing circuit and digital signal processing circuit Echo preventing circuit and digital signal processing circuit

2008-04-15

2008-04-15

Young, Brian (Department: 2819)

Coded data generation or conversion

Analog to digital conversion followed by digital to analog...

C370S289000

Reexamination Certificate

active

07358875

ABSTRACT:
An echo preventing circuit comprises a filter that is inputted with a first digital signal and outputs a second and a third digital signals; a first DA converter that converts the second digital signal into a first analog signal and outputs the first analog signal; a second DA converter that converts the third digital signal into a second analog signal and outputs the second analog signal; an input/output terminal that outputs the first analog signal or that is inputted with a third analog signal; a subtracting circuit that outputs a fourth analog signal obtained by subtracting the second analog signal from a signal formed by combining the first analog signal and the third analog signal; and an AD converter that converts the fourth analog signal into a fourth digital signal and outputs the fourth digital signal, wherein the filter sets filter coefficients for which the fourth analog signal is a signal formed by removing or attenuating the first analog signal from a signal formed by combining the first analog signal and the third analog signal, based on the fourth digital signal outputted from the AD converter when signals are inputted into the first and the second DA converters while the third analog signal is not present, and wherein the fourth analog signal outputted from the subtracting circuit is outputted as an output signal corresponding to the third analog signal.

REFERENCES:
patent: 4539675 (1985-09-01), Fisher
patent: 5075687 (1991-12-01), Chen et al.
patent: 5381474 (1995-01-01), Lahdemaki et al.
patent: 5633863 (1997-05-01), Gysel et al.
patent: 5710790 (1998-01-01), Herzberg et al.
patent: 5796819 (1998-08-01), Romesburg
patent: 6658055 (2003-12-01), Darr
patent: 6674810 (2004-01-01), Cheng
patent: 7173962 (2007-02-01), Dowling
patent: 42 02 206 (1993-07-01), None
patent: 61 030134 (1986-02-01), None
patent: 2001-060895 (2001-06-01), None
European Patent Office, Extended European Search Report for Application No. 07101389.0—1246, Jun. 13, 2007.

Affiliated with

Also associated with

Rating

Echo preventing circuit and digital signal processing circuit does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Echo preventing circuit and digital signal processing circuit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Echo preventing circuit and digital signal processing circuit will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2750325