Phase locked loop amplifier for variable amplitude radio waves
First Claim
1. An arrangement for generating an amplified modulated carrier signal the amplitude variations of which are smaller than the amplitude of the unmodulated carrier, characterized in that said arrangement comprises a first and a second controlled power oscillator, each having a control input and an output, and a control circuit connected to the respective control inputs of said first and second controlled power oscillators for making said oscillators oscillate at a substantially constant amplitude and at a frequency which substantially corresponds to the carrier frequency, the outputs of said oscillators being coupled to the control circuit for generating control signals for the oscillators from comparisons between the modulated carrier signal and the oscillator signals, the arrangement also comprising an output circuit connected to the outputs of the oscillators for vectorially assembling an output signal which is said amplified modulated carrier signal.
1 Assignment
0 Petitions
Accused Products
Abstract
A modulated carrier signal, the amplitude variations of which are smaller than the amplitude of the unmodulated carrier, is not very suitable for transmission over radio links because the required use of non-linear components, such as class-C amplifiers, result in an unwanted widening of the transmitted spectrum. According to the invention an arrangement for amplifying such a signal comprises two oscillators (16, 17) the desired relative phase of which is adjusted in a loop including a control circuit 22. On combining the oscillator signals v'"'"'k and v'"'"'g, there is produced a resulting signal r which is a replica of the input signal v having the amplitude variations. As the oscillators 16 and 17 produce signals having a constant amplitude, these signals can be easily amplified, for example by class-C amplifiers.
-
Citations
7 Claims
- 1. An arrangement for generating an amplified modulated carrier signal the amplitude variations of which are smaller than the amplitude of the unmodulated carrier, characterized in that said arrangement comprises a first and a second controlled power oscillator, each having a control input and an output, and a control circuit connected to the respective control inputs of said first and second controlled power oscillators for making said oscillators oscillate at a substantially constant amplitude and at a frequency which substantially corresponds to the carrier frequency, the outputs of said oscillators being coupled to the control circuit for generating control signals for the oscillators from comparisons between the modulated carrier signal and the oscillator signals, the arrangement also comprising an output circuit connected to the outputs of the oscillators for vectorially assembling an output signal which is said amplified modulated carrier signal.
Specification