Telecommunications – Transmitter and receiver at same station – Radiotelephone equipment detail
Reexamination Certificate
1999-02-12
2001-12-04
Hunter, Daniel (Department: 2684)
Telecommunications
Transmitter and receiver at same station
Radiotelephone equipment detail
Reexamination Certificate
active
06327483
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
The present invention claims priority from Japanese Patent Application No. 10-038456 filed Feb. 20, 1998, the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a mobile radio communication equipment and, particularly, to a mobile radio communication equipment having a function of regulating a sound volume of voice which is being listened by a user of the mobile radio communication equipment.
2. Description of Related Art
In a conventional mobile radio communication equipment having a function of regulating a sound volume of voice which is being listened by a user of the equipment, the sound volume is regulated by the user himself by manually operating a volume key preliminarily provided on the equipment so that the sound volume of listening voice becomes desirable regardless of existing environmental noise.
In such conventional radio communication equipment, however, when a sound volume on a transmitting side is small, there is a possibility that a sound volume on the receiving side becomes small necessarily, so that the user on the receiving side must manually operate the volume key, resulting in that a convenience of the user is lost. Further, the user must manually operate the volume key every time the sound volume and/or ambient noise on the receiving side varies, resulting in low operability of the equipment.
Under such circumstances, a mobile radio communication equipment provided with a noise sensor for detecting background noise has been proposed in, for example, Japanese Patent Application Laid-open No. Hei 4-822331, in which a background noise level detected by the noise sensor is compared with a threshold value based on a signal input from a key pad and a receiving sound volume of a loud-speaker is regulated correspondingly to a result of the comparison.
Further, another mobile radio communication equipment has been proposed in, for example, Japanese Patent Application Laid-open No. Hei 7-307697, in which an average value of an audio signal output from a transmitter is compared with a reference level of ambient noise, it is recognized whether or not the audio signal output from the transmitter is a transmitting sound and a receiving sound volume is automatically regulated correspondingly to the ambient noise level by controlling a gain of a variable gain amplifier for amplifying the receiving sound, on the basis of a result of the comparison and a result of the recognition.
In the former one of the above mentioned conventional mobile radio communication equipments, which is provided with the noise sensor, it is possible to automatically regulate according to the ambient noise level. However, the noise sensor dedicated to ambient noise detection must be additionally provided to the transmitter/receiver. Therefore, the number of parts of the mobile radio communication equipment is increased and a space for mounting the noise sensor is necessary in the mobile radio communication equipment, which are inconvenient for the mobile radio communication equipment which should be compact and light-weight.
According to the latter one of the conventional mobile radio communication equipment, it is possible to automatically regulate the receiving sound volume according to the level of ambient noise. However, it is necessary to confirm from the transmitting audio signal output whether or not the transmitting audio signal is a transmitting sound. In order to do so, the average value of the output audio signal from the transmitter is compared with the audio signal. However, depending upon the volume of the ambient noise, it is impossible to exactly know whether or not the audio signal is the transmitting sound. Therefore, there may be an error of receiving volume regulation, causing a problem in reliability to occur. Further, it is impossible for individual users to regulate the sound volume to values optimal for them.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a mobile radio communication equipment capable of automatically regulating a receiving sound volume while a communication is being made, without necessity of increase of the number of parts thereof and a space thereof for mounting additional circuit.
Another object of the present invention is to provide a mobile radio communication equipment capable of automatically and more reliably regulating the receiving sound volume to an optimal value while a communication is being made.
In order to achieve the above objects, a mobile radio communication equipment according to the present invention comprises receiving means for converting an audio signal received from a remote side equipment connected to a radio network into a receiving audio signal, a loudspeaker portion for converting the receiving audio signal into a voice output, a microphone portion for collecting voice of a user of the mobile radio communication equipment and converting the collected voice into a transmitting audio signal, a signal comparator portion for calculating a transmitting power value of the transmitting audio signal, comparing the transmitting power value with a reference power value, amplifying the receiving audio signal input from the receiving means with an amplification degree corresponding to a result of the comparison and supplying the amplified audio signal to the loudspeaker portion and transmitting means for transmitting the transmitting audio signal.
Since, in the present invention, the receiving audio signal of the remote side equipment received by the receiving means is output as the voice by the loudspeaker portion after amplified with the amplification degree corresponding to the result of the comparison of the transmitting power value with the reference power value performed by the signal comparison portion and converted into the voice by the loudspeaker portion, the user can automatically regulate the receiving sound volume to a value desired by the user according to the volume of the transmitting voice of the user input through the microphone portion originally provided on the mobile radio communication equipment, without necessity of manual operation of a volume key by the user and without necessity of providing a noise sensor.
The signal comparator portion may comprise a level detector for extracting a level of a predetermined frequency component of the transmitting audio signal and calculating the power value thereof, a subtractor for calculating a difference between the transmitting power value calculated by the level detector and the reference power value and an amplifier having a variable gain, the amplifier amplifying the receiving audio signal with the gain controlled such that the difference corresponding to the transmitting power value becomes the amplification degree of the amplifier and supplying the amplified receiving audio signal to the loudspeaker portion.
The level detector may be constructed such that it extracts a level of a d.c. component of the transmitting audio signal, squares the extracted level and calculates an average value of the squared d.c. component as the transmitting power value.
An initial value of the difference calculated by the subtractor is set to 0(dB), and the receiving audio signal input initially after a communication is started may be passed through the amplifier with the level of the receiving audio signal being kept as it is to the loudspeaker portion. The difference calculated by the subtractor is stored in a memory portion temporarily and is read out therefrom to control the amplification degree of the amplifier in amplifying the receiving audio signal input thereafter.
The memory portion may have a construction which stores a user data such as address note and is capable of updating a portion of the content thereof according to an instruction from the user or the receiving means.
REFERENCES:
patent: 4380824 (1983-04-01), Inoue
patent: 5175875 (1992-12-01), Yokoya et al.
patent: 5603106 (1997-02-01), Toda
patent: 6038428 (2000-0
Hunter Daniel
NEC Corporation
Nguyen Thuan T.
Scully Scott Murphy & Presser
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