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Apparatus comprising a sigma-delta modulator and method of generating a quantized signal-delta modulator

A technique for delta modulation and modulation of signals, which is applied in the equipment field of cumulative delta modulators, and can solve problems such as unsatisfactory performance.

Active Publication Date: 2007-09-05
TELEFON AB LM ERICSSON (PUBL)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The receiver will not work optimally in frequency modulation mode if a summing delta modulator is used with a dithered signal applied to the input, and on the other hand if a dithered signal is used with a quantized phase modulation mode would not be optimal since the SDM would have to be designed for one of the two modes, and the result would be in the other. Unsatisfactory performance in mode

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  • Apparatus comprising a sigma-delta modulator and method of generating a quantized signal-delta modulator
  • Apparatus comprising a sigma-delta modulator and method of generating a quantized signal-delta modulator
  • Apparatus comprising a sigma-delta modulator and method of generating a quantized signal-delta modulator

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Embodiment Construction

[0036] A schematic diagram of a frequency synthesizer 1 under accumulative delta control capable of employing the present invention is shown in FIG. 1 . The synthesizer 1 includes a phase locked loop circuit. These synthesizers can be used in a variety of applications such as transceiver systems or stand-alone receivers that can include or use a Bluetooth modem.

[0037] the reference signal f ret This reference signal (to which the phase locked loop circuit is to be tuned) is fed to a phase and / or frequency detector (PFD) 2 . This signal is usually a signal with high frequency stability. The output of the phase / frequency detector 2 is fed via a filter 3 (typically a low pass filter (LPF)) to generate the output signal f out voltage controlled oscillator (VCO)4. then signal f out Feeds back to a frequency divider (DIV) 5, and the divided signal generated by the frequency divider 5 is then applied to the other input of the phase and / or frequency detector 2, thus providing ...

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Abstract

A method of generating a quantized signal in a Sigma-Delta modulator (25) comprises the steps of feeding a modulator input signal to a quantizer (15) via at least one integrator (12, 13); generating in the quantizer (15) a quantized signal; feeding back the quantized signal to be subtracted from the modulator input signal; and generating a dither signal to be applied to a point in the Sigma-Delta modulator. The dither signal is applied to a selected one of a number of different points (11, 14) in the Sigma-Delta modulator (25) in dependence of a control signal. In this way a method of generating a quantized signal in a Sigma-Delta modulator is provided which provides optimal results for different modes of the application, such as phase modulation mode and frequency modulation mode in a Bluetooth receiver.

Description

technical field [0001] The present invention relates to a method of generating a quantized signal in a sigma-delta modulator (Sigma-deltamodulator) arranged to work with a fractional frequency divider in a frequency synthesizer used in a modulated signal receiver, the method comprising The steps of: feeding a modulator input signal to a quantizer via at least one integrator; generating a quantized signal in said quantizer; feeding back said quantized signal so as to subtract it from said modulator input signal; and generating The dither signal to be applied to a point in the summing delta modulator. The invention furthermore relates to a device comprising a summing delta modulator. Background technique [0002] Sigma-delta modulators or converters are used in several different applications, such as phase-locked loops and frequency synthesizers. In synthesizers controlled by accumulative increments, the average divisor factor makes up the integer and fractional parts. The ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03M3/02H03L7/197
CPCH03M7/3026H03M7/3033H03M7/3008
Inventor J·W·埃肯布罗克
Owner TELEFON AB LM ERICSSON (PUBL)