| 摘要 |
The decoder has a sorting circuit (10) which extracts encrypted digital signal data from an incoming data stream. The extracted data is decrypted (11) and delivered to a D/A converter (13,14) to generate an analogue signal from the recorded data. A low-pass filter (15,16) is connected to the output of the D/A converter, and delivers the audio signal in decoded form. The decryption circuit and the D/A converter are fabricated as a single component, making the output of the encryption circuit inaccessible. A digital filter circuit can be integrated with the D/A converter and the decryption circuit.
|
