Device for demodulating a spread spectrum signal

A device for demodulating a spread spectrum signal which has been direct sequence encoded with a predetermined pseudo noise code, comprising:

• decoding signal generating means for generating a first data decoding signal corresponding to the predetermined pseudo noise code;
• data demodulation means for demodulating the spread spectrum signal with the first data decoding signal to produce a first data signal;
• test signal generating means for generating a plurality of test decoding signals corresponding to the predetermined pseudo noise code, each of the test decoding signals being phase-shifted relative to any other of the test decoding signals by a predetermined amount;
• test demodulation means for spread spectrum demodulating the spread spectrum signal using the test decoding signals to produce a plurality of test signal, each test signal corresponding to the demodulation of the spread spectrum signal with a different one of the test signals;
• comparator means for comparing the strength of the test signals and the first data signal;
• decoding signal phase adjusting means responsive to the comparator means for adjusting the phase of the first data decoding signal relative to the spread spectrum signal to correspond to the phase of the test decoding signal corresponding to the strongest of the test signals whenever the strength of the strongest of the test signals exceeds the strength of the first data signal;
• and,
• test decoding signal phase adjusting means for continually adjusting the phase of the test decoding signals relative to the spread spectrum signal in a predetermined manner such that alternative phase relationships resulting in a synchronization between the test decoding signals and the spread spectrum signal can be produced.

A device for demodulating a spread spectrum signal which has been direct sequence encoded with a predetermined pseudo noise code, comprising:

• decoding signal generating means for a plurality of data decoding signals, each data decoding signal corresponding to the predetermined pseudo noise code, each of the data decoding signals being phase-shifted relative to any other of the data decoding signals by a predetermined amount;
• data demodulation means for demodulating the spread spectrum signal with the plurality of data decoding signals to produce a plurality of data signals, each data signal corresponding to the demodulation of the spread spectrum signal with a different one of the plurality of data decoding signals;
• test signal generating means for generating a plurality of test decoding signals corresponding to the predetermined pseudo noise code, each of the test decoding signals being phase-shifted relative to any other of the test decoding signals by a predetermined amount;
• test demodulation means for spread spectrum demodulating the spread spectrum signal using the test decoding signals to produce a plurality of test signal, each test signal corresponding to the demodulation of the spread spectrum signal with a different one of the test signals;
• comparator means for comparing the strength of the test signals and the data signals;
• decoding signal phase adjusting means responsive to the comparator means for adjusting the phase of the decoding signals relative to the spread spectrum signal to correspond to the phase of the test decoding signal corresponding to the strongest of the test signals whenever the strength of the test signals exceeds the strength of the data signal;
• and,
• test decoding signal phase adjusting means for continually adjusting the phase of each test decoding signal relative to the spread spectrum signal in a predetermined manner such that alternative phase relationships resulting in a synchronization between the test decoding signals and the spread spectrum signal can be produced.

A device for demodulating a spread spectrum signal which has been direct sequence encoded with a predetermined pseudo noise code, comprising:

• decoding signal generating means for generating a plurality of data decoding signal corresponding to the predetermined pseudo noise code, the data decoding signals being phase-shifted relative to the one another such that the data decoding signal can be simultaneously synchronized to the spread spectrum signal;
• a plurality of each of demodulation means for spread spectrum demodulating the spread spectrum signal with a different one of the data decoding signals to produce a plurality of data signals;
• combining means for producing a summation signal corresponding to the sum of the data decoding signals;
• comparator means for comparing the strength of the data signals;
• synchronization control means for adjusting the phase of the plurality of decoding signals relative to the spread spectrum signal so as to maintain a general synchronization between the decoding signals and the spread spectrum signal, the synchronization control means including means responsive to the comparator means and controlling the data signal generating means for incrementally adjusting the phase of the plurality of decoding signals relative to the spread spectrum signal such that the weakest of the data signals tends to be strengthened.