Radio and communication method using a transmitted intermediate frequency

A radio for receiving signals having a carrier phase shift key modulated by a subcarrier for controlling a frequency reference, said radio comprising:

• a. a frequency reference providing a local oscillator signal having a frequency substantially the same as the frequency of the carrier of the received signal;
• b. means for demodulating a received signal into a subcarrier using the local oscillator frequency;
• c. means for controlling the local oscillator signal to lock on the carrier as a function of the subcarrier;
• and
• d. means for deriving a scaled signal related to the subcarrier from the local oscillator signal wherein said means for controlling the local oscillator frequency controls the local oscillator signal based on differences between a function of the scaled signal and a function of the subcarrier from the received signal.

A radio adapted to receive and transmit signals modulated with a subcarrier, said radio comprising:

• a. means for generating a local oscillator signal for demodulating received signals and providing a carrier for transmitted signals;
• b. means for generating a local scaled signal adapted to derive from the local oscillator signal a local scaled signal providing the subcarrier for transmitted signals;
• c. means for demodulating received signals into a subcarrier using the local oscillator signal;
• d. means for regulating the local oscillator signal to lock on the carrier as a function of the subcarrier of the received signals;
• and
• e. means for modulating the local oscillator signal, scaled signal and data to provide transmitted signals.

A direct sequence spread spectrum radio transmitter comprising:

• a. a local oscillator adapted to provide an oscillator signal having a frequency of RF,
• b. a first divider circuit adapted to receive and divide the oscillator signal by N to provide a digital clock signal having a frequency RF/N,
• c. a pseudo-noise generator adapted to provide pseudo-noise codes when clocked by the digital clock signal,
• d. a second divider circuit adapted to receive and divide said digital clock signal by M to produce a scaled clock signal having a frequency RF/N/M,
• e. combining circuitry for combining data to be transmitted, pseudo noise codes, and the scaled clock signal to form a spread data signal, and
• f. a mixer adapted to receive the oscillator signal and the spread data signal to form a transmit signal.

A direct sequence spread spectrum radio receiver for receiving a transmitted signal having a frequency of RF, wherein the modulation thereon includes a data signal and a subcarrier signal, comprising:

• a. a voltage controlled radio frequency oscillator adapted to provide an oscillator signal having an initial frequency of approximately RF;
• b. a first divider circuit adapted to receive and divide the oscillator signal by N to provide a digital clock signal having an initial frequency of approximately RF/N,
• c. a pseudo-noise generator adapted to provide pseudo-noise codes when clocked by the digital clock signal,
• d. a first mixer circuit adapted to receive and mix the oscillator signal and pseudo-noise codes to provide a spread oscillator signal,
• e. a second mixer adapted to receive and mix a transmitted signal and the spread oscillator signal and provide a baseband signal having the subcarrier and data,
• f. a multiplier adapted to receive and multiply the baseband signal by a factor M to provide a multiplied baseband signal, and
• g. a phase detector adapted to receive the multiplied baseband signal and the digital clock signal to produce a frequency error signal, wherein said voltage controlled radio frequency oscillator is adapted to receive the frequency error signal and whereby the frequency of oscillator signal is corrected to RF,
• h. a second divider adapted to receive and divide digital clock signal by a factor M to provide a scaled signal corresponding to the subcarrier,
• i. a third mixer adapted to receive and mix the scaled signal and the baseband signal to recover the data.