ASK modulation circuit

Details ASK modulation circuit ASK modulation circuit

1999-08-27

2003-01-07

Corrielus, Jean (Department: 2631)

Pulse or digital communications

Transmitters

Amplitude modulation

C327S117000, C332S149000

Reexamination Certificate

active

06504880

ABSTRACT:

Japanese Patent Application No. 10-253526, filed on Aug. 28, 1998, is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to an Amplitude Shift Keying (ASK) modulating circuit, and more particularly to an ASK modulating circuit used in a transmitter.
2. Related Art
Japanese Patent Laid-Open Publication No. Hei. 10(1998)-13475 discloses a conventional ASK modulating circuit. In this ASK modulating circuit, a switching device or transistor is interposed between a power source terminal of an oscillating circuit and a direct current power source. Repeatedly turning the switching device on and off by applying a two digit signal produces an ASK modulated wave at an output terminal of the oscillating circuit.
However, in the foregoing circuit, a floating capacitance depicted with a phantom line (shown in the 10-13475 Document) is generated, such that the oscillating circuit effectively contains a capacitor. So long as the capacitor is not charged to some extent, the oscillating circuit cannot oscillate or fails to emit a carrier wave. Thus, this circuit is not suitable for high speed transmission.
Japanese Patent Laid-open Publication No. Hei. 08(1996)-191218 discloses another ASK modulating circuit which is free from the foregoing drawback. However, this ASK modulating circuit requires, for ASK modulation, additional components such a FET in addition to an oscillator. Thus, this ASK modulating circuit becomes more complex than the foregoing ASK modulating circuit.
SUMMARY OF THE INVENTION
It is, therefore, a principal object of the present invention to provide an ASK modulating circuit without the foregoing drawbacks.
In order to attain the foregoing object, the present invention provides an ASK modulating circuit which comprises an oscillation circuit generating a pulse oscillation having a given frequency and a frequency divider. The frequency divider includes a binary counter unit having at least an input terminal, an output terminal, and a reset terminal. The frequency divider is active and inactive when low and high levels of a transmission signal wave, respectively, are applied to the reset terminal thereof. The frequency divider divides the pulse oscillation while the frequency divider is active. As a result, the transmission signal wave is modulated together with a carrier frequency which is identical to the divided frequency.


REFERENCES:
patent: 3647967 (1972-03-01), Stein
patent: 3657658 (1972-04-01), Kubo
patent: 3996481 (1976-12-01), Chu et al.
patent: 4559492 (1985-12-01), Baba et al.
patent: 4672447 (1987-06-01), Moring et al.
patent: 4712335 (1987-12-01), Nelson
patent: 5235292 (1993-08-01), Endo et al.
patent: 5398007 (1995-03-01), Yamazaki et al.
patent: 5724105 (1998-03-01), Hatano
patent: 5937339 (1999-08-01), Vigne
patent: 8-191218 (1996-07-01), None
patent: 10-13475 (1998-01-01), None

Affiliated with

Also associated with

Rating

ASK modulation 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 ASK modulation circuit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and ASK modulation circuit will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3003659