Transmitter-receiver

An automatic frequency control method for use in a TDD type transmitter-receiver having an oscillator, which is capable of dividing one channel into a transmission slot and a reception slot with respect to time and performing time-divided transmission and reception of data during such slots respectively, said method comprising the steps of:

• supplying a first nonmodulated carrier signal from a transmitting circuit to a circuit during a transmission time slot;
• mixing said first nonmodulated carrier signal supplied to said receiving circuit with a local oscillation signal obtained from an oscillator, and converting the mixed signal into a first intermediate frequency signal;
• converting the frequency of said first intermediate frequency signal into a first output voltage;
• storing a representation of the value of said first output voltage in a memory means;
• receiving by said receiving circuit, during a reception time slot, a second nonmodulated carrier signal transmitted from a remote station;
• mixing said second nonmodulated carrier signal received with a local oscillation signal obtained from said oscillator, and converting the mixed signal into a second intermediate frequency signal;
• converting the frequency of said second intermediate frequency signal into a second output voltage;
• and
• controlling the oscillation frequency of said oscillator in such a manner that the level of said second output voltage becomes coincident with the value of said first output voltage stored in said memory means.

An automatic frequency control method for use in a TDD type transmitter-receiver which is capable of dividing one channel into a transmission slot and a reception slot with respect to time and performing time-divided transmission and reception of data during such slots respectively, said method comprising the steps of:

• supplying a first nonmodulated carrier signal from a transmitting circuit to a receiving circuit during a transmission time slot;
• mixing said first nonmodulated carrier signal supplied to said receiving circuit with a local oscillation signal obtained from an oscillator, and converting the mixed signal into a first intermediate frequency signal;
• converting the frequency of said first intermediate frequency signal into a first output voltage;
• storing the value of said first output voltage in a memory means;
• receiving a control signal from a remote transmitter by said receiving circuit during a reception slot;
• mixing said received control signal with said local oscillation signal obtained from said oscillator to produce a second intermediate frequency signal;
• converting the frequency of said second intermediate frequency signal into a second output voltage;
• and
• controlling the oscillation frequency of said oscillator so that the value of said second output voltage becomes coincident with the value of said first output voltage stored in said memory means.

An automatic frequency control method for a TDD type transmitter-receiver capable of dividing one channel into a transmission slot and a reception slot with respect to time and performing time-divided transmission and reception of data during such slots respectively, said method comprising the steps of:

• supplying a carrier signal from a transmitting circuit of a receiver to a receiving circuit of said transceiver for a predetermined period of time;
• mixing said carrier signal supplied to said receiving circuit with a local oscillation signal generated by an oscillation means, and converting the resulting signal into a first intermediate frequency signal;
• converting the frequency of said first intermediate frequency signal into a first output voltage;
• storing a representation of the value of said first output voltage in a memory means;
• receiving, by said receiving circuit, for a predetermined period of time, a second carrier signal from a remote transmitter;
• mixing said second carrier signal with said local oscillation signal and converting the mixed signal into a second intermediate frequency signal;
• converting the frequency of said second intermediate frequency signal into a second output voltage;
• and
• controlling the oscillation frequency of said oscillation means in such a manner that the value of said second output voltage becomes coincident with the value of said first output voltage stored in said memory means.

A TDD type transceiver capable of dividing one channel into a transmission slot and a reception slot with respect to time and performing time-divided transmission and reception of data during such slots respectively, said transceiver comprising:

• a transmitting circuit for transmitting signals to a remote receiver;
• said transmitting circuit comprising means for generating a nonmodulated carrier signal;
• a receiving circuit for receiving signals from a remote transmitter;
• a signal path for allowing said carrier signal to pass from said transmitting circuit to said receiving circuit during a transmission slot;
• said receiving circuit further comprising:
• an oscillation means for generating an oscillation signal;
• a mixer for mixing said oscillation signal with said nonmodulated carrier signal to produce an intermediate frequency signal;
• a frequency discriminator for generating a voltage in accordance with the frequency of said intermediate frequency signal;
• means for storing the value of said voltage;
• and
• means for controlling, during a receiving slot, the oscillation of aid oscillation means in accordance with said stored voltage value.

A TDD type transmitter-receiver capable of dividing one channel into a transmission slot and a reception slot with respect to time and performing time-divided transmission and reception data during such slots respectively, said transmitter-receiver comprising:

• a transmitting circuit for transmitting signals to a remote receiver,
• said transmitting circuit comprising means for generating a carrier signal;
• a receiving circuit for receiving signals from a remote transmitter,
• a signal path for allowing said carrier signal to pass from said transmitting circuit to said receiving circuit during a transmission slot;
• said receiving circuit further comprising:
• an oscillation means for generating an oscillation signal;
• said oscillation means comprising an oscillator;
• a mixer for mixing said oscillation signal with said carrier signal to produce an intermediate frequency signal;
• a frequency discriminator for generating a voltage in accordance with the frequency of said intermediate frequency signal;
• means of storing the value of said voltage;
• and
• means for controlling, during a receiving slot, the oscillation frequency of said oscillator in accordance with said stored voltage value.

A TDD type transmitter-receiver capable of dividing one channel into a transmission slot and a reception slot with respect to time and performing time-divided transmission and reception of data during such slots respectively, said transmitter-receiver comprising:

• transmitting circuit for transmitting signals to a remote receiver,
• said transmitting circuit comprising means for generating a carrier signal;
• a receiving circuit for receiving signals from a remote transmitter,
• a signal path for allowing said carrier signal to pass from said transmitting circuit to said receiving circuit during a transmission slot;
• said receiving circuit further comprising:
• an oscillation means for generating an oscillation signal at an oscillation frequency;
• a mixer for mixing said oscillation signal with said carrier signal to produce an intermediate frequency signal;
• a frequency discriminator for generating a voltage in accordance with the frequency of said intermediate frequency signal;
• means for storing a value of said voltage;
• means for controlling, during a receiving slot, the oscillation frequency of said oscillation means in accordance with said stored voltage value;
• said oscillation means comprises an oscillator;
• and
• said means for generating a carrier signal further comprises said oscillator.