Search International and National Patent Collections
Some content of this application is unavailable at the moment.
If this situation persists, please contact us atFeedback&Contact
1. (AU1991078900) Hybrid modulation apparatus

Office : Australia
Application Number: 78900/91 Application Date: 15.05.1991
Publication Number: 1991078900 Publication Date: 27.08.1992
Publication Kind : A
Prior PCT appl.: Application Number:US1991003385 ; Publication Number: Click to see the data
IPC:
H04L 27/20
H04B 14/00
H ELECTRICITY
04
ELECTRIC COMMUNICATION TECHNIQUE
L
TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
27
Modulated-carrier systems
18
Phase-modulated carrier systems, i.e. using phase-shift keying
20
Modulator circuits; Transmitter circuits
H ELECTRICITY
04
ELECTRIC COMMUNICATION TECHNIQUE
B
TRANSMISSION
14
Transmission systems not characterised by the medium used for transmission
Applicants: Motorola, Inc.
Inventors: Cahill, Stephen V
Gillig, Steven F.
Walczak, Thomas J.
Agents: PHILLIPS ORMONDE FITZPATRICK
Priority Data: 526156 21.05.1990 US
Title: (EN) Hybrid modulation apparatus
Abstract:
(EN) A $g(p)/4-shift DQPSK modulator modulates a digitized voice signal and other information. An FM modulator modulates the analog voice signal and other information. The FM modulator is coupled to the quadrature mixers (109 and 110) of the $g(p)/4-shift DQPSK modulator. When an FM modulated signal is required, the mixers (109 and 110) are biased (114) to allow carrier feedthrough by applying a fixed, non-zero DC signal to one or both mixers (109 and 110). The carrier is then FM modulated using conventional methods such as voltage-modulation of a phase locked loop (PLL) (113). When $g(p)/4-shift DQPSK is to be generated, the conventional baseband I and Q vector-length signals (101 and 102) are applied to the mixers (109 and 110), and the carrier is left unmodulated by switching (115) out the input signal to the PLL (113). The PLL (113) will then generate only the carrier frequency to be mixed with the I and Q vector-length signals (101 and 102).
Also published as:
CA2062980WO/1991/018464