Transmission power control system in a radio apparatus

A transmission power control system for use in a radio apparatus comprising a transmission side including a transmission antenna and a transmission unit provided with a receiving level data signal, said transmission unit comprising:

• first variable attenuator means for adjusting an intermediate frequency signal level;
• converter means for converting the output of said first variable attenuator to a higher frequency band signal;
• second variable attenuator means for adjusting the output level of said converter means;
• high output amplifier means for amplifying the output of said second variable attenuator to provide an amplified signal which is output to the transmission antenna;
• first transmission power control means for controlling transmission power by controlling the degree of attenuation of said first variable attenuator means;
• second transmission power control means for controlling the transmission power by controlling the degree of attenuation of said second variable attenuator means;
• and
• switching means for activating one of said first transmission power control means and said second transmission power control means in accordance with a range of the receiving level data signal,
• wherein a receiving unit of said radio apparatus includes level detecting process circuit means for outputting the receiving level data signal to said transmission side,
• said receiving level data signal being clipped at a first constant value when it is lower than the first predetermined value, being clipped at a second constant value when it is larger than the second predetermined value which is different from said first constant value, and varying along a continuous line connecting said first constant value with said second constant value where said receiving level is between the first predetermined value and the second predetermined value, and
• said transmission power control system further comprising:
• window comparator means for detecting when the receiving level data signal from said level detection process circuit is equal to said first constant value or second constant value, a second switching means outputting a clock signal to said second transmission power control means when said receiving level data signal is equal to one of said constant values.

A transmission power control system for use in a radio apparatus comprising a transmission side including a transmission antenna and a transmission unit provided with a receiving level data signal, said transmission unit comprising:

• first variable attenuator means for adjusting an intermediate frequency signal level;
• converter means for converting the output of said first variable attenuator to a higher frequency band signal;
• second variable attenuator means for adjusting the output level of said converter means;
• high output amplifier means for amplifying the output of said second variable attenuator to provide an amplified signal which is output to the transmission antenna;
• first transmission power control means for controlling transmission power by controlling the degree of attenuation of said first variable attenuator means;
• second transmission power control means for controlling the transmission power by controlling the degree of attenuation of said second variable attenuator means;
• and
• switching means for activating one of said first transmission power control means and said second transmission power control means in accordance with a range of the receiving level data signal,
• wherein a receiving unit of said radio apparatus includes level detecting process circuit means for outputting the receiving level data signal to said transmission side,
• said receiving level data signal being clipped at a first constant value when it is lower than the first predetermined value, being clipped at a second constant value when it is larger than the second predetermined value which is different from said first constant value, and varying along a continuous line connecting said first constant value with said second constant value where said receiving level is between the first predetermined value and the second predetermined value, and
• said level detecting process circuit means including
• means for amplifying an AGC control voltage and clipping maximum output voltage by a source voltage,
• attenuator means for decreasing the output of said amplifier means and for clipping the maximum output value and the minimum output value, and
• an amplifier for performing a phase conversion of the output of said attenuator means.

A method for controlling transmission power of a radio apparatus supplied with an intermediate frequency signal, comprising the steps of:

• a) attenuating a level of the intermediate frequency signal;
• b) converting the intermediate frequency signal attenuated in said step (a) into a higher frequency signal;
• c) attenuating a level of the higher frequency signal;
• d) amplifying the higher frequency signal attenuated in said step (c) to provide a transmission signal;
• e) generating a detecting signal based on the transmission signal;
• f) transmitting the transmission signal;
• g) receiving the transmission signal;
• h) generating a receiving level data signal based on the transmission signal received in said step (g);
• i) controlling the attenuating of said step (a) based on the receiving level data signal when a level of the receiving level data signal is between first and second predetermined values, the second predetermined value being greater than the first predetermined value;
• and
• j) controlling the attenuating of said step (c) based on the detecting signal and the receiving level data signal when the level of the receiving level data signal is equal to or below the first predetermined value and equal to or above the second predetermined value.