PC card and wlan system having high speed, high resolution, digital-to analog converter with off-line sigma delta conversion and storage

A WLAN communications system, comprising:

• a WLAN access point;
• and
• a PC card coupled to a computer, said PC card being capable of communicating with said WLAN access point via radio frequency (RF) communication, said PC card further comprising:
• a digital baseband;
• an RF section;
• an RF interface coupling said digital baseband to said RF section, wherein said RF interface further comprises a delta-sigma digital-to-analog converter having a digital input and an analog output comprising:
• a storage means having stored outputs of a delta-sigma converter fed by a number of predetermined interpolated samples corresponding to all possible values of said digital input;
• said storage means coupled to receive said digital input;
• a plurality of digital-to-analog converters coupled to said storage means to receive said stored outputs, said plurality of digital-to-analog converters clocked by multi-phase clocks wherein each phase applied to each of said plurality of digital to analog converters is delayed with respect to a next one by an oversampling period equal to the Nyquist period divided by the number of predetermined interpolated samples;
• and
• a summer coupled to said plurality of digital-to-analog converters for summing all output from said plurality of digital-to-analog converters to generate said analog output.

A PC card, comprising:

• a digital baseband;
• an RF section;
• an RF interface coupling said digital baseband to said RF section, wherein said RF interface comprises:
• a storage means having stored compressed outputs of a delta-sigma converter fed by a number of predetermined interpolated samples corresponding to all possible values of said digital input;
• said storage means coupled to receive said digital input;
• an expansion unit coupled to said storage means for expanding said compressed outputs;
• a plurality of digital-to-analog converters coupled to said expansion unit to receive said expanded stored outputs, said plurality of digital-to-analog converters clocked by multi-phase clocks wherein each phase applied to each of said plurality of digital to analog converters is delayed with respect to a next one by an oversampling period equal to the Nyquist period divided by the number of predetermined interpolated samples;
• and
• a summer coupled to said plurality of digital-to-analog converters for summing all output from said plurality of digital-to-analog converters to generate said analog output.

A PC card, comprising:

• circuitry for providing a digital baseband function;
• circuitry for providing an RF function;
• circuitry for providing an RF interface function, said circuitry for providing an RF interface function being coupled to said circuitry for providing a digital baseband function and said circuitry for providing an RF function, wherein said circuitry for providing an RF interface function comprises:
• a storage means having stored compressed outputs of a delta-sigma converter fed by a number of predetermined interpolated samples corresponding to all possible values of said digital input;
• said storage means coupled to receive said digital input;
• an expansion unit coupled to said storage means for expanding said compressed outputs;
• a plurality of digital-to-analog converters coupled to said expansion unit to receive said expanded stored outputs, said plurality of digital-to-analog converters clocked by multi-phase clocks wherein each phase applied to each of said plurality of digital to analog converters is delayed with respect to a next one by an oversampling period equal to the Nyquist period divided by the number of predetermined interpolated samples;
• and
• a summer coupled to said plurality of digital-to-analog converters for summing all output from said plurality of digital-to-analog converters to generate said analog output.

A WLAN communications system, comprising:

• a WLAN access point;
• and
• a PC card coupled to a computer, said PC card being capable of communicating with said WLAN access point via radio frequency (RF) communication, said PC card further comprising:
• circuitry for providing a digital baseband function;
• circuitry for providing an RF function;
• circuitry for providing an RF interface function, said circuitry for providing an RF interface function being coupled to said circuitry for providing a digital baseband function and said circuitry for providing an RF function, wherein said circuitry for providing an RF interface function comprises:
• a storage means having stored compressed outputs of a delta-sigma converter fed by a number of predetermined interpolated samples corresponding to all possible values of said digital input;
• said storage means coupled to receive said digital input;
• an expansion unit coupled to said storage means for expanding said compressed outputs;
• a plurality of digital-to-analog converters coupled to said expansion unit to receive said expanded stored outputs, said plurality of digital-to-analog converters clocked by multi-phase clocks wherein each phase applied to each of said plurality of digital to analog converters is delayed with respect to a next one by an oversampling period equal to the Nyquist period divided by the number of predetermined interpolated samples;
• and
• a summer coupled to said plurality of digital-to-analog converters for summing all output from said plurality of digital-to-analog converters to generate said analog output.