US 5,621,351 AGranted

Modulation amplifier for radio transmitters

AssigneeThomcast AG

InventorsNarindra N. Puri, Patrick Gehri, Bohumil Kyrian, Peter Niklaus, Juraj Tomljenovic, Nenad Tomljenovic

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Abstract

A modulation amplifier includes a signal converter, a summator and a plurality of high frequency stages (3.sub.1-m or 4.sub.1-n). The high frequency stages (3.sub.1-m) are driven by equiphased control signals (s.sub.1-m); the high frequency stages (4.sub.1-n) are driven by control signals (t.sub.1-n) of different phase .PHI..sub.1-n. The high frequency stages (3.sub.1-m or 4.sub.1-n) can be selected in an arbitrary manner by the control signals (s.sub.1-m or t.sub.1-n). The summator adds the high frequency output signals (x.sub.1-m or y.sub.1-n) of the high frequency stages (3.sub.1-m or 4.sub.1-n). The output signal can be conveyed, for example, to a low pass and a subsequent load. The phases (.PHI..sub.1-n) of the output signals (y.sub.1-n) of the high frequency stages (4.sub.1-n) correspond to those of the control signals (t.sub.1-m). So many high frequency stages (3.sub.1-m) are selected that there is at the output of the summator a high frequency oscillation, whose amplitude changes by steps in accordance with the low frequency signal. In addition, so many high frequency stages (4.sub.1-n) with different phases (.PHI..sub.1-n) are selected that the sum of the outputs (y.sub.1-n) corresponds to the difference of the amplified amplitude of the low frequency signal and the coarse approximation of the low frequency signal to the sum of the output signals (x.sub.1-m).

Claims11

Dependent claims

Modulation amplifier comprising

a) a signal converter, which converts a low frequency signal, applied to a low frequency input, into a first group of m(m.gtoreq.1) control signals (s.sub.1-m);
b) a high frequency oscillator, which emits a high frequency signal of frequency f.sub.0 and phase .PHI..sub.0 ;
c) m high frequency stages (3.sub.1-m), which can be driven independently and which are driven by the control signals (s.sub.1-m) and emit in the turned on state high frequency signals of frequency f.sub.0, phase .PHI..sub.0 and identical amplitude to their outputs (x.sub.1-m);
d) a summator, which adds the outputs (x.sub.1-m) of the high frequency stages (3.sub.1-m), and sends the composite signal on to a low pass filter, to whose output a load can be attached, whereby
e) the signal converter drives so many high frequency stages (3.sub.1-m) that the output signal of the summator represents a power-amplified, high frequency oscillation, whose amplitude changes by steps in accordance with the low frequency signal;
and
f) means for approximating the difference of the amplified amplitude of the low frequency signal and step-shaped output signal of the summator;
wherein
g) the means for approximating the difference of the amplified amplitude of the low frequency signal and step-shaped output signal of the summator include a second group of n, n.gtoreq.2, independently driven high frequency stages (4.sub.1-n), which
h) are driven by a second group of n high frequency control signals (t.sub.1-n), which originate from the signal converter and exhibit the same frequency f.sub.0, but different phase .PHI..sub.1-n, and
i) said high frequency stages (4.sub.1-n) send to their outputs (y.sub.1-n) high frequency signals of frequency f.sub.0, identical amplitude, but different phase .PHI..sub.1-n, whereby
j) the signal converter determines in such a manner the number of selected high frequency stages (4.sub.1-n) and their phases (.PHI..sub.1-n) that the sum of the output signals (y.sub.1-n) of the second group of high frequency stages (4.sub.1-n) represents a high frequency oscillation, whose amplitude corresponds to the difference of the amplified low frequency signal and the step-shaped representation of the low frequency signal by means of the high frequency stages (3.sub.1-m).

9 more elements

A radio transmitter comprising:

a low frequency source;
a modulation amplifier;
a load;
a low pass filter disposed between said modulation amplifier and said load;
said modulation amplifier including:
a) a signal converter, which converts a low frequency signal, applied to a low frequency input, into a first group of m(m.gtoreq.1) control signals (s.sub.1-m);
b) a high frequency oscillator, which emits a high frequency signal of frequency f.sub.0 and phase .PHI..sub.0 ;
c) m high frequency stages (3.sub.1-m), which can be driven independently and which are driven by the control signals (s.sub.1-m) and emit in the turned on state high frequency signals of frequency f.sub.0, phase .PHI..sub.0 and identical amplitude to their outputs (x.sub.1-m);
d) a summator, which adds the outputs (x.sub.1-m) of the high frequency stages (3.sub.1-m), and sends the composite signal on to a low pass filter, to whose output a load can be attached, whereby
e) the signal converter drives so many high frequency stages (3.sub.1-m) that the output signal of the summator represents a power-amplified, high frequency oscillation, whose amplitude changes by steps in accordance with the low frequency signal;
and
f) means for approximating the difference of the amplified amplitude of the low frequency signal and step-shaped output signal of the summator;
wherein
g) the means for approximating the difference of the amplified amplitude of the low frequency signal and step-shaped output signal of the summator include a second group of n, n.gtoreq.2, independently driven high frequency stages (4.sub.1-n), which
h) are driven by a second group of n high frequency control signals (t.sub.1-n), which originate from the signal converter and exhibit the same frequency f.sub.0, but different phase .PHI..sub.1-n, and
i) said high frequency stages (4.sub.1-n) send to their outputs (y.sub.1-n) high frequency signals of frequency f.sub.0, identical amplitude, but different phase .PHI..sub.1-n, whereby
j) the signal converter determines in such a manner the number of selected high frequency stages (4.sub.1-n) and their phases (.PHI..sub.1-n) that the sum of the output signals (y.sub.1-n) of the second group of high frequency stages (4.sub.1-n) represents a high frequency oscillation, whose amplitude corresponds to the difference of the amplified low frequency signal and the step-shaped representation of the low frequency signal by means of the high frequency stages (3.sub.1-m), wherein the number of high frequency stages (3.sub.1-m) is greater than the number of high frequency stages (4.sub.1-n), thus m.gtoreq.n, and in particular n=2.

14 more elements

A radio transmitter comprising:

a low frequency source;
a modulation amplifier;
a load;
a low pass filter disposed between said modulation amplifier and said load;
said modulation amplifier including:
a) a signal converter, which converts a low frequency signal, applied to a low frequency input, into a first group of m(m.gtoreq.1) control signals (s.sub.1-m);
b) a high frequency oscillator, which emits a high frequency signal of frequency f.sub.0 and phase .PHI..sub.0 ;
c) m high frequency stages (3.sub.1-m), which can be driven independently and which are driven by the control signals (s.sub.1-m) and emit in the turned on state high frequency signals of frequency f.sub.0, phase .PHI..sub.0 and identical amplitude to their outputs (x.sub.1-m);
d) a summator, which adds the outputs (x.sub.1-m) of the high frequency stages (3.sub.1-m), and sends the composite signal on to a low pass filter, to whose output a load can be attached, whereby
e) the signal converter drives so many high frequency stages (3.sub.1-m) that the output signal of the summator represents a power-amplified, high frequency oscillation, whose amplitude changes by steps in accordance with the low frequency signal;
and
f) means for approximating the difference of the amplified amplitude of the low frequency signal and step-shaped output signal of the summator;
wherein
g) the means for approximating the difference of the amplified amplitude of the low frequency signal and step-shaped output signal of the summator include a second group of n, n.gtoreq.2, independently driven high frequency stages (4.sub.1-n), which
h) are driven by a second group of n high frequency control signals (t.sub.1-n), which originate from the signal converter and exhibit the same frequency f.sub.0, but different phase .PHI..sub.1-n, and
i) said high frequency stages (4.sub.1-n) send to their outputs (y.sub.1-n) high frequency signals of frequency f.sub.0, identical amplitude, but different phase .PHI..sub.1-n, whereby
j) the signal converter determines in such a manner the number of selected high frequency stages (4.sub.1-n) and their phases (.PHI..sub.1-n) that the sum of the output signals (y.sub.1-n) of the second group of high frequency stages (4.sub.1-n) represents a high frequency oscillation, whose amplitude corresponds to the difference of the amplified low frequency signal and the step-shaped representation of the low frequency signal by means of the high frequency stages (3.sub.1-m), wherein the number of high frequency stages (4.sub.1-n) is greater than the number of high frequency stages (3.sub.1-m), thus n.gtoreq.m, and in particular m=1.

14 more elements

Dependencies are inferred from the claim text.