Transcoding and transdecoding unit, and method for adjusting the output thereof
AssigneeNokia Telecommunications Oy
InventorsReijo Leppanen, Marko Vanska
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Abstract
A transcoding and transdecoding unit in a digital mobile radio system, and methods for adjusting their output signals. The unit includes an expander for converting companded digital data into a linear signal; a speech encoder for coding a linearized signal into encoded form; and an amplifier for amplifying the expanded signal. In order that the outbound audio signal not suffer interference due to the raised level, the transcoding unit further includes a level monitor for monitoring the amplitude of the linearized signal and for controlling amplifier such that the signal produced by the amplifier is of a desired level.
Claims22
A transcoding unit in a digital mobile radio system, comprising:
- an expander unit for converting companded voice frequency digital data into an expanded linear signal;
- an amplifying means for amplifying said expanded linear signal to provide an amplified signal;
- a level-monitoring means for monitoring the amplitude of said expanded linear signal and for controlling said amplifying means such that said amplified signal produced by the amplifying means has a desired level;
- and
- a speech encoder for coding said amplified signal to provide an encoded signal.
A transdecoding unit in a digital mobile radio system, comprising:
- a speech signal decoder for converting an encoded voice frequency signal into a linear signal;
- an amplifying means for amplifying said linear signal;
- a level-monitoring means for monitoring the amplitude of said linear signal and for controlling said amplifying means such that the amplified linear signal produced by the amplifying means has a desired level;
- and
- a compander unit for companding said amplified linear signal to provide a companded signal.
A method for adjusting an output signal of a transcoding unit in a digital mobile radio system, comprising the steps of:
- expanding a companded digital signal into a linear signal;
- measuring an amplitude of the linear signal to provide a measuring result;
- adjusting amplification of the linear signal to be applied to a speech encoder on the basis of the measuring result;
- and
- speech-encoding said linear signal.
A method for adjusting an output signal of a transdecoding unit in a digital mobile radio system, the method comprising the steps of:
- speech-decoding an encoded voice frequency signal into a linear signal;
- amplifying said linear signal, using an amplifier, to provide an amplified linear signal;
- measuring the amplitude of said linear signal to provide a measuring result;
- adjusting amplification provided by said amplifier of said linear signal on the basis of said measuring result;
- and
- companding said amplified linear signal.
Dependencies are inferred from the claim text.