JPH0758936B2 - Signal identification circuit - Google Patents
Signal identification circuitInfo
- Publication number
- JPH0758936B2 JPH0758936B2 JP23193589A JP23193589A JPH0758936B2 JP H0758936 B2 JPH0758936 B2 JP H0758936B2 JP 23193589 A JP23193589 A JP 23193589A JP 23193589 A JP23193589 A JP 23193589A JP H0758936 B2 JPH0758936 B2 JP H0758936B2
- Authority
- JP
- Japan
- Prior art keywords
- signal
- circuit
- adpcm
- pcm
- khz
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000001514 detection method Methods 0.000 claims description 14
- 238000006243 chemical reaction Methods 0.000 claims description 5
- 238000010586 diagram Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 230000003044 adaptive effect Effects 0.000 description 1
- 238000011181 container closure integrity test Methods 0.000 description 1
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- Transmission Systems Not Characterized By The Medium Used For Transmission (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明はPCM符号化信号と高能率音声符号化信号とを識
別する信号識別回路に関し、特に、CCITTのG711に勧告
されているPCM信号と、G722に勧告されている帯域分割
適応差分PCM信号（以下SB−ADPCM信号という）とを識別
する信号識別回路に関する。The present invention relates to a signal discrimination circuit for discriminating a PCM coded signal from a high-efficiency voice coded signal, and particularly to a PCM signal recommended in CCITT G711. , G722 recommended band division adaptive differential PCM signal (hereinafter referred to as SB-ADPCM signal).
従来、この種の信号識別回路としては、第２図及び第３
図のそれぞれ送信側および受信側の構成図に示した様
に、送信側では、入力端子10よりPCM信号が入力し、入
力端子11よりSB−ADPCM信号が入力し、入力端子12よりP
CM信号とSB−ADPCM信号のいずれを選択するかを決める
選択信号を入力し、選択回路15にてPCM信号とSB−ADPCM
信号のいずれかを選択し、ビットスティール回路16に
て、８ビット中の下位ビットのLSBに選択信号“1"また
は“0"を入れて、出力端子13より送出する。2. Description of the Related Art Conventionally, this type of signal discrimination circuit has been shown in FIGS.
On the transmitting side, the PCM signal is input from the input terminal 10, the SB-ADPCM signal is input from the input terminal 11, and the P
Input a selection signal that determines whether to select the CM signal or SB-ADPCM signal, and select circuit 15 to select the PCM signal or SB-ADPCM signal.
One of the signals is selected, and the bit steal circuit 16 puts the selection signal "1" or "0" in the LSB of the lower bit of the 8 bits and sends it out from the output terminal 13.
受信側では、入力端子18を経て入力したPCM信号またはS
B−ADPCM信号よりLSB検出回路17にてLSBの値を検出し、
その検出結果により、切替回路14にてPCM信号ならば出
力端子19より出力し、SB−ADPCM信号ならば出力端子20
より出力する。On the receiving side, the PCM signal or S input via the input terminal 18
The LSB value is detected by the LSB detection circuit 17 from the B-ADPCM signal,
According to the detection result, the switching circuit 14 outputs the PCM signal from the output terminal 19, and the SB-ADPCM signal outputs the output terminal 20.
Output more.
上述した従来の信号識別回路では、LSBをビットスティ
ールしているために音声品質の劣化となる欠点がある。The above-described conventional signal identification circuit has a drawback that the voice quality is deteriorated because the LSB is bit stealed.
本発明は送信側において、PCM信号またはSB−ADPCM信号
のLSBをビットスティールして選択信号を挿入すること
なしに両方の信号を識別できる信号識別回路を提供する
ことにある。It is an object of the present invention to provide a signal discriminating circuit capable of discriminating both LSB and LSB of a PCM signal or SB-ADPCM signal on the transmitting side without inserting a selection signal.
本発明の信号識別回路は、送信側から送られてきたPCM
信号またはSB−ADPCM信号を直線符号に変換する非直線
／直線符号変換回路と、その直線符号の信号より3.4KHz
〜4KHz周波数帯域内の一部を通過させる帯域通過ディジ
タルフィルタと、その帯域通過ディジタルフィルタから
出力された信号の大きさを検出するパワー検出回路と、
そのパワー検出回路の検出結果により入力してきた前記
PCM信号またはSB−ADPCM信号をそれぞれの出力端子に送
出する切替回路とを有する。The signal identification circuit of the present invention is used for the PCM sent from the transmitting side.
Signal or SB-ADPCM signal is converted to a linear code by a non-linear / linear code conversion circuit and the signal of that linear code is 3.4 KHz
A band-pass digital filter that passes a part of the frequency band up to 4 KHz, and a power detection circuit that detects the magnitude of the signal output from the band-pass digital filter,
Based on the detection result of the power detection circuit,
And a switching circuit for sending the PCM signal or the SB-ADPCM signal to the respective output terminals.
次に、本発明について図面を参照して説明する。 Next, the present invention will be described with reference to the drawings.
第１図は本発明の一実施例の信号識別回路の受信側の構
成図である。１はPCM信号またはSB−ADPCM信号を入力す
る入力端子、４は入力端子より入力した信号をCCITT G
711によって非直線符号を直線符号に変換する非直線／
直線符号変換回路、５は3.4kHz〜4kHz周波数帯域内の一
部を通過させる帯域通過ディジタルフィルタ、６は信号
の有無を検出するパワー検出回路、７は入力端子１より
入力した信号をPCM信号側またはSB−ADPCM信号側に送出
する様に切替える切替回路で、２はPCM信号を出力する
出力端子、３はSB−ADPCM信号を出力する出力端子であ
る。FIG. 1 is a block diagram of a receiving side of a signal identifying circuit according to an embodiment of the present invention. 1 is an input terminal for inputting a PCM signal or SB-ADPCM signal, 4 is a signal input from the input terminal to CCITT G
Non-linear / converting non-linear code to linear code by 711 /
Linear code conversion circuit, 5 is a bandpass digital filter that allows a part of the frequency band from 3.4 kHz to 4 kHz to pass, 6 is a power detection circuit that detects the presence or absence of a signal, and 7 is the PCM signal side of the signal input from input terminal 1. Or, a switching circuit for switching to send to the SB-ADPCM signal side, 2 is an output terminal for outputting a PCM signal, and 3 is an output terminal for outputting an SB-ADPCM signal.
次に、本実施例の動作を説明する。CCITTG711のPCM信号
は0.3kHz〜3.4kHz周波数帯域の信号であるから、34kHz
〜4kHz周波数帯域内には信号が存在しない。一方、CCIT
T G722のSB−ADPCM信号は7kHz周波数帯域のうち低域を
６ビット（５ビット、４ビットの場合もある）、高域を
２ビットのADPCM符号に変換して合わせて８ビットにな
るように符号化しているため、入力してきたSB−ADPCM
信号を非直線／直線符号変換回路にてそのまま直線符号
変換すると、ランダムパターンに近い信号となる。そう
すると、その信号をPCM信号として見なすと、０〜4kHz
の全周波数帯域に信号成分が発生する。従って、帯域通
過ディジタルフィルタ５で3.4kHz〜4kHz周波数帯域内の
一部を通過させると、ある程度のレベルの信号が検出さ
れる。Next, the operation of this embodiment will be described. The CCITT G711 PCM signal is in the 0.3kHz to 3.4kHz frequency band, so 34kHz
There is no signal in the ~ 4kHz frequency band. Meanwhile, CCIT
The SB-ADPCM signal of T G722 should be converted into 6 bits (7 bits in some cases) of the 7 kHz frequency band (6 bits in some cases, 5 bits and 4 bits in some cases) and 2 bits in ADPCM code to convert it to 8 bits in total. Since it is encoded, the input SB-ADPCM
If the signal is linearly code-converted as it is by the non-linear / linear code conversion circuit, a signal close to a random pattern is obtained. Then, if that signal is regarded as a PCM signal, it is 0 to 4 kHz.
A signal component is generated in the entire frequency band of. Therefore, when a part of the frequency band of 3.4 kHz to 4 kHz is passed by the bandpass digital filter 5, a signal of a certain level is detected.
これにより入力端子１より入力した信号がPCM信号なら
ばパワー検出回路６の検出結果は信号無しとなり、SB−
ADPCM信号の場合は信号有りとなる。その検出結果によ
り切替回路７にて入力信号を切り替えてPCM信号またはS
B−ADPCM信号を識別して出力することができる。As a result, if the signal input from the input terminal 1 is a PCM signal, the detection result of the power detection circuit 6 is no signal and SB-
In the case of ADPCM signal, there is a signal. Depending on the detection result, the switching circuit 7 switches the input signal to switch the PCM signal or S
B-ADPCM signals can be identified and output.
以上説明したように、本発明は入力してきた信号がPCM
信号またはSB−ADPCM信号の場合に3.4kHz〜4kHz周波数
帯域内にある程度の信号成分が存在するか否かを検出す
ることにより、入力してきた信号がPCM信号かSB−ADPCM
信号かを検出できる効果がある。また、従来例のように
ビットスティールを行わないために音声品質を劣化させ
ない効果がある。As described above, according to the present invention, the input signal is PCM.
In the case of a signal or SB-ADPCM signal, whether the input signal is a PCM signal or an SB-ADPCM signal is detected by detecting whether or not there is a certain amount of signal component within the 3.4kHz to 4kHz frequency band.
It has the effect of detecting whether it is a signal. Further, unlike the conventional example, since bit stealing is not performed, there is an effect that voice quality is not deteriorated.
第１図は本発明の一実施例の構成図、第２図は従来例の
信号識別回路の送信側の構成図、第３図は従来例の受信
側の構成図である。 1,10,11,12,18……入力端子、2,3,13,19,20……出力端
子、４……非直線／直線符号変換回路、５……帯域通過
ディジタルフィルタ、６……パワー検出回路、７……切
替回路、15……選択回路、16……ビットスティール回
路、17……LSB検出回路。FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a block diagram of a transmitting side of a signal identifying circuit of a conventional example, and FIG. 3 is a block diagram of a receiving side of a conventional example. 1,10,11,12,18 …… Input terminal, 2,3,13,19,20 …… Output terminal, 4 …… Non-linear / linear code conversion circuit, 5 …… Band pass digital filter, 6 …… Power detection circuit, 7 ... switching circuit, 15 ... selection circuit, 16 ... bit steal circuit, 17 ... LSB detection circuit.
Claims (1)
−ADPCM信号を直線符号に変換する非直線／直線符号変
換回路と、その直線符号の信号より3.4kHz〜4kHz周波数
帯域内の一部を通過させる帯域通過ディジタルフィルタ
と、その帯域通過ディジタルフィルタから出力された信
号の大きさを検出するパワー検出回路と、そのパワー検
出回路の検出結果により入力してきた前記PCM信号また
はSB−ADPCM信号をそれぞれの出力端子に送出する切替
回路とを有することを特徴とする信号識別回路。1. PCM signal or SB sent from the transmitting side
-Non-linear / linear code conversion circuit that converts ADPCM signal to linear code, band pass digital filter that passes a part of the frequency band of 3.4 kHz to 4 kHz from the signal of the linear code, and output from the band pass digital filter A power detection circuit for detecting the magnitude of the signal, and a switching circuit for sending the PCM signal or SB-ADPCM signal input according to the detection result of the power detection circuit to the respective output terminals. Signal identification circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23193589A JPH0758936B2 (en) | 1989-09-06 | 1989-09-06 | Signal identification circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23193589A JPH0758936B2 (en) | 1989-09-06 | 1989-09-06 | Signal identification circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0394531A JPH0394531A (en) | 1991-04-19 |
| JPH0758936B2 true JPH0758936B2 (en) | 1995-06-21 |
Family
ID=16931371
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23193589A Expired - Lifetime JPH0758936B2 (en) | 1989-09-06 | 1989-09-06 | Signal identification circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0758936B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5538807A (en) * | 1992-09-03 | 1996-07-23 | Nikon Corporation | Vent valve for an amphibious equipment having a battery housing |
| JP4894904B2 (en) * | 2009-10-27 | 2012-03-14 | カシオ計算機株式会社 | Housing mounting structure and electronic device |
| CN102096279A (en) | 2009-10-27 | 2011-06-15 | 卡西欧计算机株式会社 | Housing structure and electronic device |
-
1989
- 1989-09-06 JP JP23193589A patent/JPH0758936B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0394531A (en) | 1991-04-19 |
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