Modulation amplifier for radio transmitters
First Claim
1. Modulation amplifier comprisinga) a signal converter, which converts a low frequency signal, applied to a low frequency input, into a first group of m(m≧
- 1) control signals (s1-m);
b) a high frequency oscillator, which emits a high frequency signal of frequency f0 and phase Φ
0 ;
c) m high frequency stages (31-m), which can be driven independently and which are driven by the control signals (s1-m) and emit in the turned on state high frequency signals of frequency f0, phase Φ
0 and identical amplitude to their outputs (x1-m);
d) a summator, which adds the outputs (x1-m) of the high frequency stages (31-m), and sends the composite signal on to a low pass filter, to whose output a load can be attached, wherebye) the signal converter drives so many high frequency stages (31-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;
whereing) 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≧
2, independently driven high frequency stages (41-n), whichh) are driven by a second group of n high frequency control signals (t1-n), which originate from the signal converter and exhibit the same frequency f0, but different phase Φ
1-n, andi) said high frequency stages (41-n) send to their outputs (y1-n) high frequency signals of frequency f0, identical amplitude, but different phase Φ
1-n, wherebyj) the signal converter determines in such a manner the number of selected high frequency stages (41-n) and their phases (Φ
1-n) that the sum of the output signals (y1-n) of the second group of high frequency stages (41-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 (31-m).
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Abstract
A modulation amplifier includes a signal converter, a summator and a plurality of high frequency stages (31-m or 41-n). The high frequency stages (31-m) are driven by equiphased control signals (s1-m); the high frequency stages (41-n) are driven by control signals (t1-n) of different phase Φ1-n. The high frequency stages (31-m or 41-n) can be selected in an arbitrary manner by the control signals (s1-m or t1-n). The summator adds the high frequency output signals (x1-m or y1-n) of the high frequency stages (31-m or 41-n). The output signal can be conveyed, for example, to a low pass and a subsequent load. The phases (Φ1-n) of the output signals (y1-n) of the high frequency stages (41-n) correspond to those of the control signals (t1-m). So many high frequency stages (31-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 (41-n) with different phases (Φ1-n) are selected that the sum of the outputs (y1-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 (x1-m).
107 Citations
11 Claims
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1. 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≧ - 1) control signals (s1-m);
b) a high frequency oscillator, which emits a high frequency signal of frequency f0 and phase Φ
0 ;c) m high frequency stages (31-m), which can be driven independently and which are driven by the control signals (s1-m) and emit in the turned on state high frequency signals of frequency f0, phase Φ
0 and identical amplitude to their outputs (x1-m);d) a summator, which adds the outputs (x1-m) of the high frequency stages (31-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 (31-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;
whereing) 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≧
2, independently driven high frequency stages (41-n), whichh) are driven by a second group of n high frequency control signals (t1-n), which originate from the signal converter and exhibit the same frequency f0, but different phase Φ
1-n, andi) said high frequency stages (41-n) send to their outputs (y1-n) high frequency signals of frequency f0, identical amplitude, but different phase Φ
1-n, wherebyj) the signal converter determines in such a manner the number of selected high frequency stages (41-n) and their phases (Φ
1-n) that the sum of the output signals (y1-n) of the second group of high frequency stages (41-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 (31-m). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- 1) control signals (s1-m);
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10. A radio transmitter comprising:
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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≧
1) control signals (s1-m);b) a high frequency oscillator, which emits a high frequency signal of frequency f0 and phase Φ
0 ;c) m high frequency stages (31-m), which can be driven independently and which are driven by the control signals (s1-m) and emit in the turned on state high frequency signals of frequency f0, phase Φ
0 and identical amplitude to their outputs (x1-m);d) a summator, which adds the outputs (x1-m) of the high frequency stages (31-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 (31-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;
whereing) 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≧
2, independently driven high frequency stages (41-n), whichh) are driven by a second group of n high frequency control signals (t1-n), which originate from the signal converter and exhibit the same frequency f0, but different phase Φ
1-n, andi) said high frequency stages (41-n) send to their outputs (y1-n) high frequency signals of frequency f0, identical amplitude, but different phase Φ
1-n, wherebyj) the signal converter determines in such a manner the number of selected high frequency stages (41-n) and their phases (Φ
1-n) that the sum of the output signals (y1-n) of the second group of high frequency stages (41-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 (31-m), wherein the number of high frequency stages (31-m) is greater than the number of high frequency stages (41-n), thus m≧
n, and in particular n=2.
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11. A radio transmitter comprising:
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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≧
1) control signals (s1-m);b) a high frequency oscillator, which emits a high frequency signal of frequency f0 and phase Φ
0 ;c) m high frequency stages (31-m), which can be driven independently and which are driven by the control signals (s1-m) and emit in the turned on state high frequency signals of frequency f0, phase Φ
0 and identical amplitude to their outputs (x1-m);d) a summator, which adds the outputs (x1-m) of the high frequency stages (31-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 (31-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;
whereing) 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≧
2, independently driven high frequency stages (41-n), whichh) are driven by a second group of n high frequency control signals (t1-n), which originate from the signal converter and exhibit the same frequency f0, but different phase Φ
1-n, andi) said high frequency stages (41-n) send to their outputs (y1-n) high frequency signals of frequency f0, identical amplitude, but different phase Φ
1-n, wherebyj) the signal converter determines in such a manner the number of selected high frequency stages (41-n) and their phases (Φ
1-n) that the sum of the output signals (y1-n) of the second group of high frequency stages (41-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 (31-m), wherein the number of high frequency stages (41-n) is greater than the number of high frequency stages (31-m), thus n≧
m, and in particular m=1.
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Specification