JPS6240829A - Modem training signal detector - Google Patents
Modem training signal detectorInfo
- Publication number
- JPS6240829A JPS6240829A JP18018185A JP18018185A JPS6240829A JP S6240829 A JPS6240829 A JP S6240829A JP 18018185 A JP18018185 A JP 18018185A JP 18018185 A JP18018185 A JP 18018185A JP S6240829 A JPS6240829 A JP S6240829A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- training signal
- modem
- detected
- circuit
- 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.)
- Granted
Links
Landscapes
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
Abstract
Description
【発明の詳細な説明】
〔概要〕
雑音や入力信号のパワーに関係なく、位相的にトレーニ
ング信号の中心周波数を検出し、更にこの検出期間に高
周波側のモデムトレーニング信号を検出することで、音
声信号中より誤検出することもなく、確実にモデムトレ
ーニング信号を検出するようにしたものである。[Detailed Description of the Invention] [Summary] By detecting the center frequency of the training signal phase-wise, regardless of noise or the power of the input signal, and further detecting the modem training signal on the high frequency side during this detection period, the voice The modem training signal is reliably detected without erroneously detecting the signal.
本発明は、ＣＣＩＴＴ勧告■・２９における交互パター
ン送出時のモデムトレーニング信号を検出するモデムト
レーニング信号検出器の改良に関する。The present invention relates to an improvement of a modem training signal detector for detecting a modem training signal when transmitting an alternating pattern according to CCITT Recommendation 1.29.
音声信号を効率よく伝送する為に、多種の符号化方式が
提案されている。Various types of encoding methods have been proposed to efficiently transmit audio signals.
内でもＡＤＰＣＭ符号化方式の有効性は広く認められて
いる。Among these, the effectiveness of the ADPCM encoding method is widely recognized.
このＡＤＰＣＭ符号化方式は音声信号の統計的性質を利
用しデータ圧縮を行うものであるが、現存する通信網に
適用を計る時は、ＦＡＸ等に利用する音声帯域モデム信
号の９６００ｂｐｓ以下は勿論９６００ｂｐｓ以」−の
データ伝送も可能であることが望ましい。This ADPCM encoding method compresses data by using the statistical properties of voice signals, but when applying it to existing communication networks, it is of course possible to use 9600bps, which is lower than the 9600bps of the voiceband modem signal used for FAX etc. It is desirable that the following data transmission be possible.
これを実現するために、本出願人である出願コード５２
２ （富士通株式会社）が昭和６０年８月１日符号（６
）で特許出願した適応差分符号化装置がある。In order to achieve this, the applicant, application code 52
2 (Fujitsu Ltd.) changed its code on August 1, 1985 (6
) There is an adaptive differential encoding device for which a patent application has been filed.
これは、音声信号の場合はこれに最適なＡＤＰＣＭ符号
化方弐とし、モデムトレーニング信号を検出した場合は
モデム信号に最適なＡＤＰＣＭ符号化方式に変更するも
のである。In the case of a voice signal, the most suitable ADPCM encoding method is used, and when a modem training signal is detected, the ADPCM encoding method is changed to the most suitable ADPCM encoding method for the modem signal.
このように、モデムトレーニング信号を検出する必要が
あるが、この場合モデムトレーニング信号検出器として
は、確実に検出出来ることが望ましい。In this way, it is necessary to detect the modem training signal, and in this case, it is desirable for the modem training signal detector to be able to detect it reliably.
第２図は従来例のモデムトレーニング信号検出器のブロ
ック図である。FIG. 2 is a block diagram of a conventional modem training signal detector.
図中１は５００Ｈｚパン１′バスフイルタ（以下Ｂ Ｐ
Ｆと称す）、２は１７００ＨｚＢＰＦ、３は２９００
ＨｚＢＰＦ、４〜７は２乗平均を求めるフィルタ、８〜
１０は乗算器、１１〜］３は比較器、１４はアンド回路
を示す。1 in the figure is a 500Hz pan 1' bus filter (hereinafter referred to as B P
F), 2 is 1700Hz BPF, 3 is 2900
HzBPF, 4-7 are filters that calculate the mean square, 8-
10 is a multiplier, 11-]3 is a comparator, and 14 is an AND circuit.
ＣＣＴＴＴ、Ｖ・２９に規定されているトレーニング信
号としては単純な繰り返し２波形であるＡ・Ｂパターン
（交互パターン）を選び、これは５００ Ｈｚ 、
１７００ Ｈｚ 、 ２９００ ＨＺの周波数Ｆ２，
２９００ＨｚＢＰＦ３に通し、その出力を夫々２乗平均
を求めるフィルタ５〜７を通しパワーを求め、比較器１
１〜１３にて、しきい値と比較し、これ以上のレー、ル
である比較器１１〜１３の出力をアンド回路１４にてア
ンドをとり、出力がルベルの時をトレーニング信号検出
としている。As the training signal specified in CCTTT, V.29, we chose the A/B pattern (alternating pattern), which is a simple repeating two waveform, and this has a frequency of 500 Hz.
Frequency F2 of 1700 Hz, 2900 Hz,
2900Hz BPF 3, and the output is passed through filters 5 to 7 for calculating the root mean square to obtain the power, and then the comparator 1
1 to 13 are compared with the threshold value, and the outputs of the comparators 11 to 13 that are equal to or higher than the threshold value are ANDed in an AND circuit 14, and when the output is equal to or less than the threshold value, the training signal is detected.
この時のしきい値レベルとしては、２乗平均を求めるフ
ィルタ４にて入力信号のパワーを検出し、このパワーに
比例し、月つ回線の周波数特性等を加味する為に、乗算
器８〜ＩＯにて乗算する係数を、夫々ａ、ｂ、ｃとして
いる。At this time, the threshold level is determined by the power of the input signal detected by the filter 4 that calculates the root mean square, and proportional to this power, and multipliers 8 to 8 to take into account the frequency characteristics of the line. The coefficients to be multiplied by IO are a, b, and c, respectively.
しかしながら、回線の雑音の周波数特性の変動、異なる
周波数特性の回線を使用する場合等があり、確実に選択
出来るしきい値の設定が困難で、従って確実にトレーニ
ング信号を検出することが困難である問題点がある。However, it is difficult to set a threshold that can be reliably selected due to fluctuations in the frequency characteristics of line noise and cases where lines with different frequency characteristics are used, making it difficult to reliably detect training signals. There is a problem.
上記問題点は、入力側に、モデムのキャリア周波数を中
心に限られた範囲内で引き込み動作可能な位相同期回路
と、モデム信号帯域の上限に中心周波数をもつバンドパ
スフィルタとを備え、該位相同期回路の出力を用いて入
力するキャリア周波数の信号の同期検波を行った結果の
符号が、予め定められた期間変化がなく、且つこの予め
定められた期間内に該バンドパスフィルタの出力パワー
が予め定められたしきい値以上であることでモデムトレ
ーニング信号を検出するようにした本発明のモデムトレ
ーニング信号検出器により解決される。The above problem is solved by equipping the input side with a phase synchronization circuit that can perform pull-in operation within a limited range around the modem's carrier frequency, and a bandpass filter with a center frequency at the upper limit of the modem signal band. The sign of the result of synchronous detection of the input carrier frequency signal using the output of the synchronous circuit does not change for a predetermined period, and the output power of the bandpass filter does not change within this predetermined period. This problem is solved by the modem training signal detector of the present invention, which detects a modem training signal when the signal exceeds a predetermined threshold.
本発明によれば、モデムのキャリア周波数（トレーニン
グ信号の中心周波数）を中心に限られた範囲内で引き込
み動作可能な位相同期回路の出力を用いて入力するキャ
リア周波数の信号の同期検波を行った結果の符号が、予
め定められた期間変化がないことで、回線の雑音及び周
波数特性によるレベルの変化に関係なく、位相的にトレ
ーニング信号を検出し、更にモデム信号帯域の−１−、
限に中心周波数（交互パターンの高周波側のモデムＩ・
レーニング信号の周波数）をもつバンドパスフィルタに
て、トレーニング信号の高周波側の信号も検出し、音声
信号よりトレーニング信号を誤検出することを更に防ぐ
ようにし、確実にモデムトレーニング信号を検出出来る
ようにしている。According to the present invention, synchronous detection of an input carrier frequency signal is performed using the output of a phase synchronization circuit that can perform pull-in operation within a limited range around the carrier frequency of the modem (the center frequency of the training signal). Since the sign of the result does not change for a predetermined period of time, the training signal can be detected phase-wise, regardless of level changes due to line noise and frequency characteristics.
center frequency (modem I on the high frequency side of the alternating pattern)
The high-frequency side signal of the training signal is also detected using a bandpass filter with a frequency of the training signal, which further prevents false detection of the training signal from the audio signal, and ensures that the modem training signal can be detected reliably. ing.
第１図は本発明の実施例のモデムトレーニング信号検出
器のブロック図である。FIG. 1 is a block diagram of a modem training signal detector according to an embodiment of the present invention.
図中１５．１９．２４〜２７は乗算器、１６はローパス
フィルタ（以下ＬＰＦと称す）、１７は零交差識別器、
１８は位相同期回路（以下ＰＬＬ回路と称す）、２０は
アンド回路、２１はカウンタ、２６．２７は遅延素子、
２８はリミッタ、２９は加算器、３０は符号検出器を示
し、尚全図を通じ同一符号は同一機能のものを示す。In the figure, 15.19.24-27 are multipliers, 16 is a low-pass filter (hereinafter referred to as LPF), 17 is a zero-crossing discriminator,
18 is a phase locked circuit (hereinafter referred to as PLL circuit), 20 is an AND circuit, 21 is a counter, 26.27 is a delay element,
28 is a limiter, 29 is an adder, and 30 is a code detector, and the same code indicates the same function throughout the drawings.
第１図はトレーニング信号の交互パターン区間における
、キャリア周波数である１７００Ｈｚの信号を以下説明
する信号検出器で検出し、音声信号の内パワーの小さい
モデム信号帯域の上限周波数である２９００Ｈｚの信号
を選び、２９００ＨｚＢＰＦを通して検出するものであ
る。Figure 1 shows that a signal with a carrier frequency of 1700 Hz in the alternating pattern section of the training signal is detected by the signal detector described below, and a signal of 2900 Hz, which is the upper limit frequency of the modem signal band with the lowest power of the voice signal, is selected. , 2900Hz BPF.
この１７００ＢＰＦ２．ＰＬＬ回路１８１乗算器１．５
，２２．ＬＰＦ１６．零交差識別器１７゜カウンタ２１
よりなる信号検出回路は、本出願人が昭和６０年６月２
０日特願昭６０−１３４６３８にて特許出願した信号検
出回路に該当するもの波数のトレーニング信号ＣＯ３θ
°ｎとＰＬＬ回路１８の乗算器２３よりの出力の虚数成
分５ｉｎ（θ。＋ω）ｎとを乗算器２２にて乗算した結
果の信号の、正か負かを検出する符号検出器３０、その
出力に小さい符号検出器の正の常数αを乗算する乗算器
２５、その出力を、加算器２９．リミッタ２８．遅延素
子２７よりなるオフセント周波数を制限する積分回路の
出力周波数ωと、入力１により、信号ｅ゛ω を得、こ
のＰ Ｌ Ｌ回路１８の乗算器２３に信号 ｅｊ９°を
入力する発振器が引き込める周波数をωの範囲に制限し
て、θ゛＝θ。＋ωとなるように適応制御し、乗算器Ｃ
ｏｓθ′ｎとを乗算して直流成分及び入力周波数の倍成
分を得、周波数１６にて直流成分を取り出し、零交差識
別器１７にて零交差がないことで信号周波数成分を検出
してアンド回路２０に入力している。This 1700BPF2. PLL circuit 181 multiplier 1.5
, 22. LPF16. Zero crossing discriminator 17° counter 21
The signal detection circuit consisting of
The training signal CO3θ of the wave number corresponding to the signal detection circuit for which the patent application was filed in Japanese Patent Application No. 60-134638
A sign detector 30 detects whether the signal obtained by multiplying °n by the imaginary component 5in(θ.+ω)n of the output from the multiplier 23 of the PLL circuit 18 in the multiplier 22 is positive or negative; A multiplier 25 multiplies the output by a positive constant α of the small sign detector, and the output is sent to an adder 29 . Limiter 28. The output frequency ω of the integrating circuit that limits the offset frequency consisting of the delay element 27 and the input 1 are used to obtain the signal e゛ω, and the oscillator that inputs the signal ej9° to the multiplier 23 of the PLL circuit 18 is pulled in. Limiting the frequency to the range of ω, θ゛=θ. +ω, and the multiplier C
osθ'n to obtain a DC component and a component double the input frequency, extract the DC component at frequency 16, detect the signal frequency component by the zero crossing discriminator 17 based on the absence of zero crossings, and perform an AND circuit. 20 is entered.
ここでθ″＝２πｆｃ’ ／ｆｓ
但しｆｃ’ は入力する信号の周波数
ｆｓはサンプリング周波数
一方トレーニング信号の２９００Ｈｚの信号は、第２図
の従来例の場合と同様な方法で檎出しアンド回路２０に
人力し、両者が検出された継続時間を、カウンタ２１に
て予め定めた時間（交互パターン送出時間）であるかを
調べ、これ以上ならトレーニング信号が検出されたとし
ている。Here, θ''=2πfc'/fs, where fc' is the frequency of the input signal fs is the sampling frequency, while the training signal of 2900 Hz is input to the AND circuit 20 in the same manner as in the conventional example shown in FIG. The counter 21 manually checks whether the duration of both detections is equal to a predetermined time (alternate pattern transmission time), and if it is longer than this, it is determined that a training signal has been detected.
このように位相変化及び継続時間で、トレーニング信号
の１７００Ｈｚの信号を検出するようにすれば、回線の
雑音及び回線によるレベル変動にも影響されなく又音声
信号の中よりも誤って検出されることは殆どなく確実に
検出されるが、又更に上記位相変化のない継続時間に、
トレーニング信号の２９００Ｈｚの信号も検出子ること
で更に誤検出を防ぎ、トレーニング信号の検出を確実な
ものにしている。By detecting the 1700 Hz signal of the training signal using the phase change and duration in this way, it will not be affected by line noise and level fluctuations due to the line, and will not be detected erroneously than in the audio signal. There is almost no phase change and it is detected reliably, but furthermore, during the duration without phase change,
The 2900 Hz signal of the training signal is also used as a detector to further prevent false detection and ensure the detection of the training signal.
この場合の２９００８２のトレーニング信号の検出は、
サブ的なものである為、この場合のしきい値としては、
この２９００Ｈｚ周波数部分の雑音が非常に増加した場
合は、２９００Ｈｚの信号がなくとも検出することもや
むを得ない程度のものでよく、従来例の場合程シビャア
なものでなくともよいわけである。In this case, the detection of 290082 training signals is as follows:
Since it is a sub-item, the threshold value in this case is
If the noise in the 2900 Hz frequency portion increases significantly, it may be unavoidable to detect it even if there is no 2900 Hz signal, and it does not have to be as severe as in the case of the conventional example.
尚２９００Ｈｚのトレーニング信号の検出にも、１７０
０Ｈｚのトレーニング信号を検出する回路と同じ信号検
出回路を用いることも考えられるが、これではバー゛ド
が大きくなるし、２９００Ｈ２のトレーニング信号の検
出は、サブ的なものである為これ程シビャアに検出しな
くとも十分である。It should be noted that 170 Hz is required for detection of a 2900 Hz training signal.
It is possible to use the same signal detection circuit as the circuit that detects the 0Hz training signal, but this would result in a large signal, and since the training signal of the 2900H2 is a sub-detection, it would not be necessary to detect it as severely. It is enough without it.
以上詳細に説明せる如く本発明によれば、モデムト、レ
ーニング信号を確、実に検出出来る効果がある。As explained in detail above, according to the present invention, modem and training signals can be detected reliably and accurately.
第１図は本発明の実施例のモデムトレーニング信号検出
器のブロック図、
第２図は従来例のモデムトレーニング信号検出器のブロ
ック図である。
図において、
１は５００ Ｈｚバンドパスフィルタ、２は１７００Ｈ
ｚバンドパスフイルタ、３は２９００ Ｈｚバンドパス
フィルタ、４〜７は２乗平均を求めるフィルタ、
８〜１０，１５．２２〜２５は乗算器、１１〜１３は比
較器、
１４、．２０はアンド回路、
１６はローパスフィルタ、
１７は零交差識別器、
１８は位相同期回路、
２１はカウンタ、
２６．２７は遅延素子、
２８はリミッタ、
２９は加算器、
３０は符号検出器を示す。FIG. 1 is a block diagram of a modem training signal detector according to an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional modem training signal detector. In the figure, 1 is a 500 Hz bandpass filter, 2 is a 1700H
z band pass filter, 3 is a 2900 Hz band pass filter, 4 to 7 are filters for calculating the mean square, 8 to 10, 15. 22 to 25 are multipliers, 11 to 13 are comparators, 14, . 20 is an AND circuit, 16 is a low-pass filter, 17 is a zero-crossing discriminator, 18 is a phase locked circuit, 21 is a counter, 26.27 is a delay element, 28 is a limiter, 29 is an adder, and 30 is a code detector .
Claims (1)
囲内で引き込み動作可能な位相同期回路と、モデム信号
帯域の上限に中心周波数をもつバンドパスフィルタとを
備え、 該位相同期回路の出力を用いて入力するキャリア周波数
の信号の同期検波を行つた結果の符号が、予め定められ
た期間変化がなく、 且つこの予め定められた期間内に該バンドパスフィルタ
の出力パワーが予め定められたしきい値以上であること
でモデムトレーニング信号を検出するようにしたことを
特徴とするモデムトレーニング信号検出器。[Claims] The input side includes a phase synchronization circuit that can perform pull-in operation within a limited range around the carrier frequency of the modem, and a bandpass filter having a center frequency at the upper limit of the modem signal band. The sign of the result of synchronous detection of the input carrier frequency signal using the output of the phase-locked circuit does not change for a predetermined period, and the output power of the bandpass filter does not change within this predetermined period. 1. A modem training signal detector, characterized in that a modem training signal is detected when the signal is greater than or equal to a predetermined threshold.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18018185A JPS6240829A (en) | 1985-08-16 | 1985-08-16 | Modem training signal detector |
| CA000511595A CA1288867C (en) | 1985-06-20 | 1986-06-13 | Adaptive differential pulse code modulation system |
| US06/876,455 US4788692A (en) | 1985-06-20 | 1986-06-20 | Adaptive differential pulse code modulation system |
| DE8686108409T DE3686674T2 (en) | 1985-06-20 | 1986-06-20 | ADAPTIVE DIFFERENTIAL PULSE CODE MODULATION SYSTEM. |
| EP86108409A EP0206273B1 (en) | 1985-06-20 | 1986-06-20 | Adaptive differential pulse code modulation system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18018185A JPS6240829A (en) | 1985-08-16 | 1985-08-16 | Modem training signal detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6240829A true JPS6240829A (en) | 1987-02-21 |
| JPH0548973B2 JPH0548973B2 (en) | 1993-07-23 |
Family
ID=16078801
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18018185A Granted JPS6240829A (en) | 1985-06-20 | 1985-08-16 | Modem training signal detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6240829A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS581975A (en) * | 1981-06-26 | 1983-01-07 | Shin Kobe Electric Mach Co Ltd | Output control of fuel cell |
| JPS63227228A (en) * | 1987-03-17 | 1988-09-21 | Fujitsu Ltd | Detector for modem training signal |
| JP2003080059A (en) * | 2001-09-10 | 2003-03-18 | Yaskawa Electric Corp | Method and apparatus for treating material using reactive gas |
| JP2006286306A (en) * | 2005-03-31 | 2006-10-19 | Tokyo Electron Ltd | Plasma processing method, plasma processing device and auto-learning program of matching unit |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5111503A (en) * | 1974-07-19 | 1976-01-29 | Nippon Electric Co |
-
1985
- 1985-08-16 JP JP18018185A patent/JPS6240829A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5111503A (en) * | 1974-07-19 | 1976-01-29 | Nippon Electric Co |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS581975A (en) * | 1981-06-26 | 1983-01-07 | Shin Kobe Electric Mach Co Ltd | Output control of fuel cell |
| JPS63227228A (en) * | 1987-03-17 | 1988-09-21 | Fujitsu Ltd | Detector for modem training signal |
| JPH0526379B2 (en) * | 1987-03-17 | 1993-04-15 | Fujitsu Ltd | |
| JP2003080059A (en) * | 2001-09-10 | 2003-03-18 | Yaskawa Electric Corp | Method and apparatus for treating material using reactive gas |
| JP2006286306A (en) * | 2005-03-31 | 2006-10-19 | Tokyo Electron Ltd | Plasma processing method, plasma processing device and auto-learning program of matching unit |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0548973B2 (en) | 1993-07-23 |
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| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |