Monitoring circuit for a descrambling device
AssigneeFujitsu Limited
InventorShinichiro Aoki
Life of this patent
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Abstract
A monitoring circuit for a descrambling device where one or more scrambled digital signals are descrambled by a first pseudo noise sequence generator which is triggered by a codeword detector. The monitoring circuit comprises a second pseudo noise sequence generator which is triggered by the codeword detector, a discriminator for discriminating between the two signals output by the first and second pseudo noise generators, a gate circuit for transmitting the output signal of the discriminator for a predetermined time and a monitoring signal generator for converting the output signal of the gate circuit into a monitoring signal.
Claims12
A monitoring circuit, operatively connected to a codeword detector which generates a codeword detector signal upon the detection of a predetermined codeword in a received signal, and operatively connected to a first pseudo noise sequence generator which generates a first pseudo noise sequence signal, for a descrambling device where at least one received signal is descrambled by the first pseudo noise sequence signal, and wherein the first pseudo noise sequence generator is triggered by the codeword detector signal, comprising:
- a second pseudo noise sequence generator, operatively connected to the codeword detector, for generating a second pseudo noise sequence signal when triggered by the codeword detector signal received from the codeword detector, the electrical structures of the first pseudo noise sequence generator and said second pseudo noise sequence generator being equivalent;
- a discriminator, having first and second inputs operatively connected to the first pseudo noise sequence generator and said second pseudo noise sequence generator, respectively, for discriminating between the first and second pseudo noise sequence signals, and for generating a pulse-shaped signal when the first and second pseudo noise sequence signals are different;
- gate means, having first and second inputs operatively connected to the codeword detector and said discriminator, respectively, for transmitting the pulse-shaped signal received from said discriminator therethrough for a first predetermined time period after said gate means is triggered by the codeword detector signal said gate means comprising:
- a gate signal generator, having an input operatively connected to the codeword detector, and having an output, for generating a gate signal, wherein the time-period of the gate signal is the first predetermined time period, after said gate signal generator is triggered by the codeword detector signal;
- and
- an AND gate having first and second inputs operatively connected to the output of said gate signal generator and said discriminator, respectively, and having an output;
- and
- a monitoring signal generator, operatively connected to the output of said AND gate, for converting the pulse-shaped signal transmitted from said gate means into a monitoring signal.
A monitoring circuit, operatively connected to a codeword detector which generates a codeword detector signal, and operatively connected to receive first and second demodulator signals, for a descrambling device, comprising:
- a first pseudo noise sequence generator, operatively connected to the codeword detector, for generating a first pseudo noise sequence signal when the codeword detector signal is received;
- a second pseudo noise sequence generator, operatively connected to the codeword detector, for generating a second pseudo noise sequence signal when the codeword detector signal is received;
- first means, having a first input operatively connected to said first pseudo noise sequence generator and having a second input operatively connected to receive the first demodulator signal, for generating a first data signal from the first pseudo noise sequence signal and the first demodulator signal;
- second means, having a first input operatively connected to said first pseudo noise sequence generator and having a second input operatively connected to receive the second demodulator signal, for generating a second data signal from the second pseudo noise sequence signal and the second demodulator signal;
- a discriminator, having first and second inputs operatively connected to said first and second pseudo noise sequence generators, respectively, for discriminating between the first and second pseudo noise sequence signals, and for generating a pulse shaped signal when the first and second pseudo noise sequence signals are different;
- gate means, having first and second inputs operatively connected to the codeword detector and said discriminator, respectively, for transmitting therethrough the pulse shaped signal when said gate means is operatively activated by the codeword detector signal, said gate means comprising:
- a gate signal generator, having an input operatively connected to the codeword detector, and having an output, for generating a gate signal, wherein the time period of the gate signal is a first predetermined time period, after said gate signal is operatively activated by the codeword detector signal;
- and
- an AND gate having first and second inputs operatively connected to the output of said gate signal generator and said discriminator, respectively, and having an output;
- and
- a monitoring signal generator, operatively connected to the output of said AND gate, for converting the pulse shaped signal into a monitoring signal.
Dependencies are inferred from the claim text.