Spread spectrum pulse position modulation communication system

A spread spectrum pulse position modulation receiver, comprising:

• an input for receiving a signal from a spread spectrum pulse position modulation transmitter;
• a splitter for dividing the received signal into first, second and third intermediate frequency signals;
• a carrier wave reproducing circuit for generating a first carrier wave from the first intermediate frequency signal;
• a phase shifter for performing a 90° phase shift on the first carrier wave to produce a second carrier wave orthogonal to the first carrier wave;
• two frequency converters for receiving and converting the second and third intermediate frequency signals and the first and second carrier waves into the I-channel baseband signal and Q-channel baseband signal;
• two matched filters for outputting a pulse when one of a pseudonoise code used in the transmitter and an inverted code used in the transmitter is input as one of the two baseband signals and reproducing the pulse position modulated signal including positive and negative pulses;
• two peak amplitude polarity detecting circuits, each of which detects a positive pulse and a negative pulse from the respective one of the two matched filters, separately, and outputs two peak detection signals;
• four peak interval measuring circuits, each of which measures a peak interval time for a respective one of the peak detection signals indicating detection of one of a positive pulse and a negative pulse for a corresponding one of the I channel and the Q channel;
• and
• four data symbol reproducing circuits, which receive the 4 peak intervals and reproduce four original data symbols as transmitted.