JPH0818629A - Reception signal frequency characteristic correction system and handset used for the system - Google Patents

Abstract

PURPOSE:To correct the frequency characteristics of reception signals while monitoring the frequency characteristics of actual sound to ear by supplying synthetic output for which respective frequency band reception signal levels are controlled to the receiver of a handset. CONSTITUTION:A microphone 3 for detecting the actual sound to ear is mounted to the recessed surface 2 of the earpiece of this handset 1, the back surface of the microphone 3 is completely sealed and the microphone 3 detects only sound on the front surface of the recessed surface 2 of the earpiece of the handset 1. The detection signal level of respective frequency bands for which the signals of the reception input are divided into plural is compared with the reception signal level of the respective frequency bands for which the signals of the output point of a pickup amplifier 7 for amplifying the output of the microphone 3 which detects the actual sound to ear are divided into plural. By the difference, the frequency characteristics are corrected in a frequency correction circuit 6 and the frequency of actual ear reception sound is reproduced so as to be flat. Thus, even though the earpiece of the handset is lightly held to an ear or strongly held to the ear, flat and easily listenable reception sound quality in a desired band is obtained at all times.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for correcting the frequency characteristic of a received signal and a handset used in the method.

[0002]

2. Description of the Related Art In conventional telephone communication, for example, when the caller has a hearing loss, the frequency of a received signal is modified so that the frequency characteristic of a receiver or a receiving circuit is adjusted to a characteristic in which high frequencies are emphasized. Compensation measures have been taken for the characteristics.

[0003]

However, during a normal telephone call, when the earpiece of the handset is put on the ear to make a telephone call, the sound quality of the earpiece changes depending on how the earpiece is placed on the ear. That is, when the earpiece is lightly applied to the ear, a gap is created between the earpiece and the ear, and the low range of the sound (real ear sound) between the earpiece and the ear leaks, and it seems to be faint. It produces a hard sound. If you put the earpiece firmly on your ear,
The gap between the earpiece and the ear becomes smaller, the amount of leakage of the received sound in the low frequency range becomes smaller, and the sound quality is flat and easy to hear from the low frequency range to the high frequency range. However, in this way, if you apply it firmly, your ears will hurt, or you will be applying it firmly, but the way you apply it will become loose, resulting in a low-volume received sound with the low range attenuated.

An object of the present invention is that regardless of how the earpiece of the handset is applied to the ear, the sound between the earpiece and the ear (real ear sound) is always flat in a desired frequency band and is easy to hear. Thus, there is provided a reception signal frequency characteristic correction method capable of correcting the frequency characteristic of the reception signal while monitoring the frequency characteristic of the real ear sound, and a handset used for the method.

[0005]

In order to achieve this object, the reception signal frequency characteristic correction method according to the present invention is arranged to detect a real ear reception sound only on the surface side of the earpiece of the handset. According to a comparison output of each frequency band detection signal level obtained by dividing the output of the detection microphone into a plurality of frequencies and each frequency band reception signal level obtained by dividing the reception input into the same number as the plurality of the reception inputs, an output in which each frequency band reception signal level is controlled is output. The synthetic output obtained by the synthesis is supplied to the handset of the handset. Further, the handset according to the present invention has a structure in which a detection microphone is arranged on the earpiece surface of the handset to detect the real ear received sound only on the surface side of the earpiece surface.

[0006]

1 is a block diagram showing a schematic structure of the method of the present invention, and FIG. 2 is a perspective view (a) and a sectional view (b) showing a structural example of a handset according to the present invention. Earpiece 1A of handset 1 as shown in FIGS. 1 and 2A and 2B
A microphone 3 for detecting a real ear sound is mounted on the concave surface 2. Reference numeral 4 is a receiver, 5 is a receiver amplifier, 6 is a frequency characteristic correction circuit, and 7 is a pickup amplifier. 8 is rubber,
It is a packing of silicone, epoxy, or the like, and is provided so that the back surface of the microphone 3 is completely sealed and the microphone 3 detects only the sound on the front side of the recessed surface of the earpiece 1A of the handset 1. In FIG. 1, the detection signal level A of each frequency band obtained by dividing the signal at the reception input signal point into a plurality of signals, and the signal at the output point of the pickup amplifier 7 that amplifies the output of the microphone 3 that has detected the actual ear sound. The received signal level B of each frequency band obtained by dividing is compared with each other, and the frequency characteristic is corrected by the frequency correction circuit 6 by the difference dEi to flatten the frequency of the real ear received sound (for example, lowering the low frequency range). It can be played (without doing).

FIG. 3 shows an example of the frequency characteristic correction circuit 6, in which the signals at the signal points obtained by properly amplifying the output of the real ear reception detection microphone 3 are bandpass filters 61-1 to 61-i. , Center frequencies f ₁ , f ₂ ,
It is divided into frequency bands f ₃ , ..., F _i . After the division as described above, the logarithmic compressors 62-1 to 62-i are divided for each band.
Connect to each. Further, the reception input signal S _in is the same center frequency f in the bandpass filters 64-1 to 64-i.
_It is divided into frequency bands of ₁ , f ₂ , f ₃ , ... F _i . After the division in this way, the logarithmic compressor 67-
1 to 67-i, and amplifiers 62-1 to 62-i which can be connected in parallel and whose amplification degree can be controlled by an external input
Connect to each. The band output level A of the real ear receiving sound of the same frequency band and the band output level B of the receiving signal input S _in are respectively compared by the comparators 63-1 to 63-i, and the level difference becomes a prescribed level difference. The gains of the variable gain amplifiers 65-1 to 65-i whose gains can be controlled by external inputs are adjusted so that The bands of the outputs of the variable gain amplifiers 65-1 to 65-i are combined by the combining circuit 66, input to the reception drive amplifier 5, and sound is output from the receiver 4. 62-1 to 62-i and 67-1 to 6
Reference numeral 7-i is a logarithmic compressor inserted to widen the comparison level range of the comparators 63-1 to 63-i.

The level comparison and the control operation for achieving the specified level difference will be further described. The output of the real-ear receiving-sound detection microphone 3 is the band-pass filter 61.
After passing through -1 to 61-i, the logarithmic compressors 62-1 to 62-62
-I logarithmically compress (A). After the reception input signal S _in passes through the band pass filters 64-1 to 64-i, it is logarithmically compressed by the logarithmic compressors 67-1 to 67-i (B), and the gain is changed by the external input voltage in parallel connection. Amplifier (VCA) 65
Enter -1 to 65-i. The difference dEi = B-A between the logarithmically compressed signals A and B is taken, and the gains of the variable gain amplifiers 65-1 to 65-i are controlled by the voltage of B-A. When the earpiece 1A of the handset 1 is applied to the ear lightly and the output to the signal point of the actual ear receiving sound detection microphone 3 is small, A is small and B-A is large, and B-A
Is large, the gains of the variable gain amplifiers 65-1 to 65-i are large, and the received sound from the real ear is increased to a required level from a small state. On the contrary, when the earpiece 2 of the handset 1 is strongly applied to the ear and the output of the real ear reception detection microphone 3 is large, A is large and B-A is small, and B-A is small.
Since A is small, the gains of the variable gain amplifiers 65-1 to 65-i are small, and the received sound from the real ear is reduced to a required level.

FIG. 4 shows another example of the frequency characteristic correction circuit 6, in which the output to the signal point of the real ear reception detection microphone 3 is band-pass filters 61-1 to 61-.
After dividing by i, the dividing circuit (a / b) is used as the signal b.
68-1 to 68-i, respectively. Further, the reception input signal S _in is the band pass filters 64-1 to 64-i.
After dividing by, the dividing circuits 68-1 to 6-6 are provided as the signal a.
Input to 8-i. Division circuits 68-1 to 68
The output of -i is input to each of the multiplication circuits 69-1 to 69-i. In addition, the setting values d _{1 to} d _i are input to the multiplication circuits 69-1 to 69-i by the constant generation circuits 71-1 to 71-.
Input each from i. Multiplier circuits 69-1 to 69-
The output of i is input to the step control circuits 70-1 to 70-i, respectively. Step control circuits 70-1 to 70-i
Are output to the variable gain amplifiers 65-1 to 65-i as the gain control signals of the variable gain amplifiers 65-1 to 65-i while giving a stepwise change in control level. When the output to the signal point of the real ear received sound detection microphone 3 is small, the signal b becomes small and the outputs of the division circuits 68-1 to 68-i become large. The outputs of the multiplication circuits 69-1 to 69-i are (a / b)
The output becomes xd, which is a / b times the set value d, that is, a large output is input to each of the step control circuits 70-1 to 70-i. Step control circuits 70-1 to 70-i
Increases the gains of the variable gain amplifiers 65-1 to 65-i stepwise. As a result, the real ear received sound becomes louder and the output of the real ear received sound detecting microphone 3 becomes louder.

In the correction circuits shown in FIGS. 3 and 4, when the real-ear receiving sound of each band is controlled to a required level, a flat real-ear receiving sound can be realized from the low range to the high range. FIG. 5 is a frequency characteristic of a real ear received sound showing an example thereof, (1) when the earpiece 1A is lightly applied to the ear, (2) when the earpiece 1A is strongly applied to the ear, (3) Shows the case where correction is made flat according to the present invention. The dEi indicated by the arrow is the difference corrected by the present invention as described above.

Although the case where the earpiece 1A has the dented surface 2 has been described above, when the earpiece surface has a flat shape without a dented surface, the earpiece 1 is placed inside the auricle when applied to the ear. The detection microphone may be arranged on the face of the earpiece at the opposite position.

[0012]

As described above in detail, according to the present invention, even if the earpiece of the handset is lightly or strongly applied to the ear, a flat and easy listening sound quality can be always obtained in a desired band. It has a great effect when applied to a handset that receives a telephone signal.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the system of the present invention.

FIG. 2 is a perspective view (a) and a sectional view (b) showing a structural example of a handset according to the present invention.

FIG. 3 is a block diagram showing an example of a frequency characteristic correction circuit used in the method of the present invention.

FIG. 4 is a block diagram showing another example of the frequency characteristic correction circuit used in the method of the present invention.

FIG. 5 is a characteristic diagram for explaining the operation of the method of the present invention.

[Explanation of symbols]

1 Handset 1A Handset earpiece 2 Dent surface 3 Detection microphone 4 Handset 5 Earphone amplifier 6 Frequency characteristic correction circuit 7 Pickup amplifier 8 Packing 61-1 to 61-i, 64-1 to 64-i Bandpass filter 62-1 to 62-i, 67-1 to 67-i Logarithmic compressor 63-1 to 63-i Comparator 65-1 to 65-i Variable gain amplifier 66 Combining circuit 68-1 to 68-i Dividing circuit 69-1 to 69 -I multiplication circuit 70-1 to 70-i step control circuit 71-1 to 71-i constant generation circuit L _r reception line

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuhiko Sagara 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation

Claims (2)

[Claims] 1. A frequency band detection signal level obtained by dividing the output of a detection microphone arranged to detect a real ear reception sound only on the surface side of the earpiece surface of the handset,
According to a comparison output with the reception signal level of each frequency band obtained by dividing the reception input into the same number as the plurality, the combined output obtained by combining the outputs controlling the reception signal level of each frequency band is supplied to the handset receiver. Received signal frequency characteristic correction method configured in. 2. A handset in which a detection microphone is arranged on the earpiece surface of the handset for detecting a real ear received sound only on the surface side of the earpiece surface.