Peak detection apparatus

摘要

An apparatus for detecting peaks of positive and negative polarity in an information signal. The apparatus comprises a first peak detector means for detecting the positive peaks and a second peak detector for detecting the negative peaks. The first peak detector means comprises a first capacitor, and has an attack time for charging the first capacitor (32) and a decay time for discharging the first capacitor, the attack time being shorter than the decay time. The first peak detector has an output for generating an output signal (42) having a first output signal value when the first peak detector is in a charging state for charging the first capacitor and having a second output value when the first peak detector is in a non-charging state. The first peak detector maintains the first capacitor charged at a first level (Vt) during time intervals that the information signal level is below said first level, said first level being larger than the zero signal level and the first peak detector is further in the charged state when the information signal level exceeds the charging level of the first capacitor. The second peak detector means comprises a second capacitor, and has an attack time for charging the second capacitor and a decay time for discharging the second capacitor, the attack time being shorter than the decay time. The second peak detector has an output (16) for generating an output signal having a third output signal value when the second peak detector is in a charging state for charging the second capacitor and having a fourth output value when the second peak detector is in a non-charging state. The second peak detector is adapted to maintain the second capacitor charged at a second level (Vt) during time intervals that the absolute value of said information signal level is below said second level, said second level being larger than the zero signal level. The second peak detector is further in the charged state when the absolute value of the information signal level exceeds the charging level of the second capacitor.