Signal waveform detection circuit

A signal waveform detection circuit comprising:

• an amplifier circuit including a plurality of differential amplifiers connected in series, each of the differential amplifiers having a common connection point;
• a comparing circuit connected to the common connection points of the amplifier circuit, the comparing circuit including a plurality of comparing units connected to respective ones of the differential amplifiers, each of the comparing units including
• a threshold voltage generating circuit for generating a plurality of signals each of which has a threshold voltage that is set between a maximum threshold voltage of a signal output from the corresponding differential amplifier during a maximum amplitude output and a minimum threshold voltage of a signal output from the corresponding differential amplifier during a minimum amplitude output, and
• a comparator connected to the common connection point of the corresponding differential amplifier and the threshold voltage generating circuit, the comparator comparing a voltage at the common connection point with the threshold voltage provided by the threshold voltage generating circuit and outputting a comparison signal;
• and
• a parallel/serial conversion and header/footer adding circuit connected to the comparing circuit, the parallel/serial conversion and header/footer adding circuit converting the comparison signals to a serial signal, adding a header signal to a head portion of the serial signal and adding a footer signal to an end portion of the serial signal.

A signal waveform detection circuit comprising:

• a filter circuit including a plurality of filters, and a plurality of amplifiers each of which is connected between the filters, each of the amplifiers outputting a threshold voltage signal;
• a first comparing circuit connected to the amplifiers of the filter circuit, the first comparing circuit including a plurality of first comparing units connected to respective ones of the amplifiers, each of the first comparing units including
• a first threshold voltage generating circuit for generating a plurality of first signals each of which has a threshold voltage that is set between a first maximum threshold voltage of a signal output from the corresponding amplifier during a maximum amplitude output and a first minimum threshold voltage of a signal output from the corresponding amplifier during a minimum amplitude output, and
• a first comparator connected to the corresponding amplifier and the first threshold voltage generating circuit, the first comparator comparing a voltage of the threshold voltage signal with the threshold voltage provided by the first threshold voltage generating circuit and outputting a first comparison signal;
• an amplifier circuit connected to the filter circuit, the amplifier circuit including a plurality of differential amplifiers connected in series, each of the differential amplifiers having a common connection point;
• a second comparing circuit connected to the common connection points of the amplifier circuit, the second comparing circuit including a plurality of second comparing units connected to respective ones of the differential amplifiers, each of the second comparing units including
• a second threshold voltage generating circuit for generating a plurality of second signals each of which has a threshold voltage that is set between a second maximum threshold voltage of a signal output from the corresponding differential amplifier during a maximum amplitude output and a second minimum threshold voltage of a signal output from the corresponding differential amplifier during a minimum amplitude output, and
• a second comparator connected to the common connection point of the corresponding differential amplifier and the second threshold voltage generating circuit, the second comparator comparing a voltage at the common connection point with the second threshold voltage provided by the second threshold voltage generating circuit and outputting a second comparison signal;
• and
• a parallel/serial conversion and header/footer adding circuit connected to the first and second comparing circuits, the parallel/serial conversion and header/footer adding circuit converting the first and second comparison signals to a serial signal and adding a header signal to a head portion of the serial signal and adding a footer signal to an end portion of the serial signal.