Conversion filtering for digital signaling systems

Details Conversion filtering for digital signaling systems Conversion filtering for digital signaling systems

1990-05-30

1992-06-30

Safourek, Benedict V.

Pulse or digital communications

Repeaters

Testing

375 60, 371 43, 332107, H04L 2704, H04L 2712, H04L 2720

Patent

active

051270242

ABSTRACT:
One way to increase the bandwidth efficiency of a linear modulation scheme is to increase the number M of possible signaling levels. Such an increase is achieved however at the expense of a smaller minimum distance d.sub.min between the multilevels, for a fixed average signal power. The present invention involves the use of a conversion filter as part of a digital signaling system used over a communications channel of limited bandwidth and power. A conventional linear digital signaling system consists of an encoder, a shaping filter, a modulator and a bandpass filter. In the present invention, the digital signaling system consists of an encoder, a conversion filter, a modulator and a passband filter. The conventional filter increase the bandwidth efficiency of the scheme when its impulse response spreads over L signaling intervals. Such an increase is achieved however, at the expenses of a smaller d.sub.min. By increasing the modulation index h of the conversion filter, it is possible to increase d.sub.min. The invention also provides steps for choosing the modulation index h, the cutoff frequency f.sub.oo of the bandpass filter and the spread L of the conversion filter such that d.sub. min is locally maximized for a fixed bandwidth efficiency and a fixed complexity of the receiver.

REFERENCES:
patent: 4229821 (1980-10-01), de Jagor et al.
patent: 4358853 (1982-11-01), Qureshi
patent: 4426710 (1984-01-01), Pommier
patent: 4438413 (1984-03-01), Ryan
patent: 4445094 (1984-04-01), Ryan
patent: 4583236 (1986-04-01), Kromer et al.
patent: 4586182 (1986-04-01), Gallager
patent: 4686688 (1987-08-01), Chung et al.

Affiliated with

Also associated with

Rating

Conversion filtering for digital signaling systems does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Conversion filtering for digital signaling systems, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Conversion filtering for digital signaling systems will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1870887