Transformar un receptor analógico de AM para recibir DRM

Hola, como saberis el DRM ( es un sistema de transmision digital de radio via AM (OC, OL , OM) . Pues hay un programa que, conectando un receptor de radio normal al ordenador te permite escuchar esas emisones . Lo que pasa es que me dice que tengo que sacar una frecuencia de 12Khz del receptor , y no sé como lo hacerlo.
Aquí lo explica :
Digital Radio Mondiale (DRM) is a new digital radio standard for the long-, medium- and short-wave ranges. The standard was formed by a consortium in co-operation with the International Telecommunication Union (ITU). The new system offers the radio stations and new service providers access to the multimedia age with small bit rates for large target areas and long distances. For more informaciónrmation visit
The bandwidth of a DRM bandpass signal is less than 20 kHz and the number of carriers used in the OFDM-modulation is relatively small (max. 460). These features motivate a real-time software implementation of a DRM-receiver on a conventional personal computer (PC) using the sound card as the input and output device. A long, medium and short wave front-end with an intermediate frequency (IF) between 5 kHz and 15 kHz is used to receive the DRM signal. Any commercial front-end with an IF of 455 kHz should be usable by adding a 455 kHz to 12 kHz adaptor (assumed the receiver bandwidth is sufficient for a DRM signal). Documentation of receiver modifications for DRM reception can be found at

With this software project we intend to implement a working software receiver with, at least, the basic features. Since this project is created at a university and the fundamental idea of such an institution is to teach and stimulate the creativity, this source-code is free under the GNU-General Public License (GPL). Dream is a development project which uses the open source model to improve DRM technology. The main aim of this project is to implement and test new research results on an existing system, whereby the synchronization and channel estimation is of special interest.

The programming-language is C++. The code runs under Microsoft Windows and Linux. Start of the project was June 2001.

Although this software is going to be distributed as free software under the terms of the GPL this does not mean that its use is free of rights of others. The use may infringe third party IP and thus may not be legal in some countries.

The intended audience of the Dream software are people who are interested in how to decode a DRM stream and want to learn from the algorithms used in this software and people who want to help us improving the performance of the receiver and the source code.

If you just want to get the experience of DRM digital sound quality and expect a very stable and optimized receiver performance, we recommend to buy the commercial DRM Software Radio.
Gracias adelantadas :) .
Es decir , que tengo que hacer un convertidor que me convierta la frecuencia intermedia de 455Khz a una de 12Khz. Alguien me puede ayudar ??

Un detector DRM se hace con un detector de producto con un oscilador local de 467 khz, la diferencia con la FI de 455 da una señal de 12 khz.
La señal para este detector hay que extraerla antes de la FI de 455, o sea a la salida del mezclador en nuestro receptor.
El mezclador utlizado para esa funcion es un NE 612 el cual lleva incorporado internamente un oscilador Colpitts, el cual puede configurarse para que oscile a una frecuencia inferior que la frecuencia del resonador utilizado, un CSB 470, en este caso necesitamos que resuene a una frecuencia ligeramente menor o sea a 467 khz, en la salida de dicho integrado tendremos la señal de audio con una frecuencia central de 12 khz y un ancho de banda de 10 khz.
Para procesar esta señal hay que atacar la entrada de una targeta de sonido que estara instalada en nuestra computadora.
Tendremos que ejecutar el programa llamado "Dream", el cual se puede bajar de internet.

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