Pulse or digital communications – Apparatus convertible to analog
Patent
1996-12-16
1998-06-09
Vo, Don N.
Pulse or digital communications
Apparatus convertible to analog
375298, 375308, 455553, 455574, 455102, 332119, H04L 2732
Patent
active
057646929
ABSTRACT:
A dual-mode frequency and phase RF modulator (11) for use in a transmitter of a radiotelephone. A dual-mode modulation approach is employed wherein, in the analog (FM) mode of operation, a phase modulator, such as a .pi./4-shift DQPSK modulator, is bypassed and may be powered down. A frequency modulated RF carrier is coupled through a bypass circuit (52) to a modulator output node (50) for transmission from the radiotelephone. In the digital mode of operation, the bypass signal path is disabled, the .pi./4-shift DQPSK modulator is enabled, and in-phase (I) and quadrature (Q) signals are input to the .pi./4-shift DQPSK modulator which provides a phase modulated RF carrier that is coupled to the modulator output node for transmission from the radiotelephone. The teaching of this invention can be employed with radiotelephones having, by example, TDMA/analog capability or CDMA/analog capability.
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Product Brochure, "ICs For Communications, GSM Transmitter Circuit PBM 2200", Siemens, Ed. 5.90 (1990).
Le Amanda T.
Nokia Mobile Phones Ltd.
Vo Don N.
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