Uniform amplitude modulator

Details Uniform amplitude modulator Uniform amplitude modulator

1998-12-02

2001-05-29

Kinkead, Arnold (Department: 2817)

Modulators

Phase shift keying modulator or quadrature amplitude modulator

C375S298000, C375S300000, C375S305000, C375S308000

Reexamination Certificate

active

06239666

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a modulator for generating a waveform by digital processing in a communication apparatus and, more particularly, to a modulation system for making the amplitude of a transmission waveform uniform.
In an apparatus for generating an analog waveform signal to be transmitted by a modulator using digital processing in data transmission, a modulator for outputting an analog signal waveform with reference to data of a memory device using an input signal as an address is known (see, e.g., Japanese Patent Laid-Open No. 62-85538).
FIG. 1
shows a modulator disclosed in this reference. This modulator comprises two memory devices
11
and
12
for generating quadrature and in-phase components of an analog waveform like the one shown in FIG.
2
.
The modulator shown in
FIG. 1
comprises the two memory devices
11
and
12
for generating quadrature and in-phase components of an analog waveform, and two D/A converters
13
and
14
for converting digital values from the memory devices
11
and
12
into analog values. The memory device is generally large in circuit scale. As the precision of an output signal increases, the circuit scale further increases, posing a problem in downsizing the modulator. The D/A converter greatly consumes the power for a higher speed and higher precision, posing a problem in reducing power consumption of the modulator.
SUMMARY OF THE INVENTION
The present invention has been made to solve the above problem, and has as its object to provide a modulator capable of reducing the circuit scale and power consumption by reducing the scales of the memory device and D/A converter.
To achieve the above object, according to the present invention, there is provided a uniform amplitude modulator comprising means for receiving data represented by phase information and generating in-phase and quadrature components as analog signal components, and means for receiving the in-phase and quadrature components and generating a modulated signal whose amplitude is uniform, one of the means for generating in-phase and quadrature components being constituted by a device for outputting an analog signal component having any one of three, predetermined positive and negative values associated with the phase information, and 0, and the other being constituted by a device for outputting an analog signal component associated with the phase information.


REFERENCES:
patent: 3849595 (1974-11-01), Ishiguro
patent: 4696017 (1987-09-01), Masheff et al.
patent: 62-85538 (1987-04-01), None
patent: 4-252634 (1992-09-01), None
patent: 4-255140 (1992-09-01), None

Affiliated with

Also associated with

Rating

Uniform amplitude modulator does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Uniform amplitude modulator, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Uniform amplitude modulator will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2477427