Programmable modem apparatus for transmitting and receiving digital data, design method and use method for the modem
View Patent ↗The programmable modem for digital data of the present invention provides a highly programmable, digital modem implemented in an integrated circuit which can be customized to specific applications. The programmable modem uses spread spectrum techniques and is specifically programmable to alter the parameters of the modem to improve performance. The present invention also provides a systematic method and development kit to provide rapid customization of a modem for a particular application or for rapid specification of a high-performance application specific integrated circuit mode.
1. A method for transmitting spread spectrum signals, comprising:
dividing an input data signal among a plurality of parallel segments of transmission data;
spreading each of the plurality of parallel segments to form parallel spread signals using orthogonal or semi-orthogonal PN codes;
summing the parallel spread signals to generate a sum signal;
digitally filtering the sum signal to generate a baseband signal;
converting the baseband signal to an intermediate frequency signal; and
transmitting the intermediate frequency signal.
2. A method for processing spread spectrum signals at a transmitting side, comprising:
dividing an input data signal among a plurality of parallel segments of transmission data;
spreading each of the plurality of parallel segments to form parallel spread signals using orthogonal or semi-orthogonal PN codes;
summing the parallel spread signals to generate a sum signal;
providing a single up-converter configured to receive the sum signal; and generating a baseband signal based on the sum signal.
3. The method of claim 2 , wherein generating the baseband signal comprises digitally filtering the sum signal.
4. An integrated circuit that processes spread spectrum signals at a transmitting side, comprising:
a divider that receives an input data signal and divides the input data signal among a plurality of parallel segments of transmission data;
a spreader responsive to the plurality of segments of transmission data to form parallel spread signals using orthogonal or semi-orthogonal PN codes;
a summer responsive to the parallel spread signals to generate a sum signal;
a digital filter responsive to the sum signal to generate a baseband signal;
a converter responsive to the baseband signal to generate an intermediate frequency signal; and
a transmitter circuit configured to transmit the intermediate frequency signal.
5. The integrated circuit of claim 4 , wherein the filter is a Nyquist filter.
6. The integrated circuit of claim 4 , wherein the filter is an over-sampling filter.
7. The integrated circuit of claim 4 , further comprising a microprocessor core configured to control the spreader.
8. The integrated circuit of claim 4 , wherein the spreader comprises a plurality of spreaders and the summer comprises a plurality of summers.
9. The integrated circuit of claim 8 , wherein each of the plurality of parallel segments of transmission data is spread and summed by respective one of the plurality of spreaders and the plurality of summers.
10. The integrated circuit of claim 8 , wherein the plurality of spreaders and the plurality of summers are arranged in a master/slave configuration.
11. A system for processing spread spectrum signals at a transmitter side, the system comprising:
a divider responsive to an input data signal to divide the input data signal among a plurality of parallel segments of transmission data;
a spreader responsive to the plurality of segments of transmission data to form parallel spread signals using orthogonal and/or semi-orthogonal PN codes;
a summer responsive to the parallel spread signals to generate a sum signal;
a digital filter responsive to the sum signal to generate a baseband signal;
a converter responsive to the baseband signal to generate an intermediate frequency signal; and
a transmitter circuit that transmits the intermediate frequency signal.
12. A system for transmitting spread spectrum signals, the system comprising:
means for dividing an input data signal among a plurality of parallel segments of transmission data;
means for spreading each of the plurality of parallel segments to form parallel spread signals using orthogonal or semi-orthogonal PN codes;
means for summing the parallel spread signals to generate a sum signal;
means for digitally filtering the sum signal to generate a baseband signal;
means for converting the baseband signal to an intermediate frequency signal; and
means for transmitting the intermediate frequency signal.