16-QAM Modulator with PLL amplification devices

Patent 4571549 Issued on February 18, 1986. Estimated Expiration Date:

January 9, 2004. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

Demodulator for combined digital amplitude and phase keyed modulation signals
Patent #: 4039961
Issued on: 08/02/1977
Inventor: Ishio , et al.

Method for generating modem transmission signals with quadrature amplitude modulation Patent #: 4327439
Issued on: 04/27/1982
Inventor: Gockler , et al.

Inventors

Assignee

Societe Anonyme de Telecommunications

Application

No. 06/569482 filed on 01/09/1984

US Classes:

332/103, PHASE SHIFT KEYING MODULATOR OR QUADRATURE AMPLITUDE MODULATOR332/185, MISCELLANEOUS375/298, Quadrature amplitude modulation455/110, Angle modulation455/113, With frequency control455/42Frequency or phase modulation

Examiners

Primary: LaRoche, Eugene R.
Assistant: Mis, D. C.

Attorney, Agent or Firm

Lowe, King, Price & Becker

International Classes

H04L 27/34 (20060101)
H04L 27/36 (20060101)

Foreign Application Priority Data

1983-01-07 FR

Abstract

A 16-quadrature amplitude modulation (QAM) modulator for radio links converts a train of data into signals having a phase selected from sixteen predetermined phase values and an amplitude selected from four values. The modulator divides the data train into two data sub-trains. The two data sub-trains are respectively applied to a pair of four-phase modulators that are fed by a carrier source. The 16-QAM modulator also comprises two phase locked loops each including a voltage controlled microwave oscillator and an associated differential phase detector. The differential phase detector responds to the output of the associated four-phase modulator and the output of the associated voltage controlled microwave oscillator. Predetermined parts of the output signals of the two phase locked loops are added.