JPH08331195A - Frequency comparison method - Google Patents
Frequency comparison methodInfo
- Publication number
- JPH08331195A JPH08331195A JP7152750A JP15275095A JPH08331195A JP H08331195 A JPH08331195 A JP H08331195A JP 7152750 A JP7152750 A JP 7152750A JP 15275095 A JP15275095 A JP 15275095A JP H08331195 A JPH08331195 A JP H08331195A
- Authority
- JP
- Japan
- Prior art keywords
- point
- signal
- symbol
- received
- frequency
- 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
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
- Synchronisation In Digital Transmission Systems (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、直交振幅変調（ＱＡ
Ｍ）信号を受信する受信装置において、ＱＡＭ信号を復
調するために、受信搬送波と再生搬送波との周波数差を
検出する周波数比較方法に関し、特に、この周波数差の
検出を短時間で実施できるようにしたものである。BACKGROUND OF THE INVENTION The present invention relates to quadrature amplitude modulation (QA
M) A frequency comparison method for detecting a frequency difference between a received carrier and a reproduced carrier in order to demodulate a QAM signal in a receiving device for receiving a signal, and particularly to enable detection of this frequency difference in a short time. It was done.
【０００２】[0002]
【従来の技術】ＱＡＭでは、π／２位相が異なる搬送波
のそれぞれに振幅の変化を与え、これらの信号を合成し
て伝送する。一方、受信側では、受信信号を２つに分岐
し、その片方に発振器で生成した再生搬送波を、また他
方には再生搬送波の位相をπ／２移相した信号を乗算し
て復調を行ない、直交する各成分の振幅値を取り出し、
それらの振幅値の組み合わせで表される多値を復号す
る。2. Description of the Related Art In QAM, changes in amplitude are given to carriers having different π / 2 phases, and these signals are combined and transmitted. On the other hand, on the receiving side, the received signal is split into two, one of which is multiplied by the reproduced carrier wave, and the other is multiplied by a signal obtained by shifting the phase of the reproduced carrier wave by π / 2 for demodulation, Take out the amplitude value of each orthogonal component,
Decode a multivalue represented by a combination of those amplitude values.
【０００３】この直交する２成分の振幅値の組み合わせ
を表すＱＡＭの各シンボル点及び受信信号点は、直交す
るＩ軸とＱ軸とで構成されるＩＱ平面上に表示すること
ができる。この受信信号点は、受信信号をＩＱ平面上に
表したものであり、またシンボル点は、ＩＱ平面上で搬
送波対ノイズ比が理論上最良となる点を表している。図
５は、このＩＱ平面の第１象限を表示したものであり、
６４ＱＡＭにおける各シンボル点を黒丸で表している。
今後の説明は、このＩＱ平面の第１象限のみを対象とし
て行なうが、この説明は他の象限を考慮しても一般性を
失わない。また、シンボルまたは受信信号点の原点０か
らの距離を振幅と呼ぶことにする。Each QAM symbol point and received signal point representing a combination of two orthogonal component amplitude values can be displayed on an IQ plane composed of orthogonal I and Q axes. The received signal points represent the received signal on the IQ plane, and the symbol points represent the theoretically best carrier-to-noise ratio on the IQ plane. FIG. 5 shows the first quadrant of this IQ plane,
Each symbol point in 64QAM is represented by a black circle.
In the following description, only the first quadrant of the IQ plane will be described, but this description does not lose generality even if other quadrants are considered. Further, the distance of the symbol or the received signal point from the origin 0 will be referred to as the amplitude.
【０００４】送信側の搬送波（受信搬送波）の周波数
と、受信装置で生成する再生搬送波の周波数とが一致し
ていない時には、同じ信号を連続して受信した場合、図
１１に示すように、受信信号点がＩＱ平面上で原点０を
中心に回転するように観測される。受信装置では、復調
に際して、この回転角と信号の受信時間間隔とから受信
搬送波と再生搬送波との周波数差を求め、それを補正す
るように再生搬送波の周波数を制御したり、あるいはこ
の周波数差を考慮した信号処理を行なう。When the frequency of the carrier wave on the transmission side (reception carrier wave) does not match the frequency of the reproduced carrier wave generated by the receiver, when the same signal is continuously received, as shown in FIG. The signal points are observed to rotate around the origin 0 on the IQ plane. At the time of demodulation, the receiving device determines the frequency difference between the received carrier wave and the reproduced carrier wave from this rotation angle and the signal reception time interval, controls the frequency of the reproduced carrier wave so as to correct it, or controls this frequency difference. Perform signal processing with consideration.
【０００５】ところで、図５に示すように、シンボル点
には、同じ振幅を持つ他のシンボル点が同一象限内に存
在するもの（円周上に複数のシンボル点が乗っているも
の）と、振幅の等しいシンボル点が同一象限内では他に
存在しないもの（円周上に１つのシンボル点だけが乗っ
ているもの）とがある。後者のシンボル点を単独シンボ
ルと呼び、また、対応するシンボルが単独シンボルであ
る受信信号を単独信号と呼ぶことにする。６４ＱＡＭの
場合、単独シンボルのＩＱ平面上での位相はπ／４であ
る。By the way, as shown in FIG. 5, among the symbol points, other symbol points having the same amplitude are present in the same quadrant (a plurality of symbol points on the circumference). There are some symbol points with the same amplitude that do not exist within the same quadrant (one symbol point is on the circumference). The latter symbol point is called a single symbol, and a received signal whose corresponding symbol is a single symbol is called a single signal. In the case of 64QAM, the phase of the single symbol on the IQ plane is π / 4.
【０００６】図１１のように、受信信号点がＩＱ平面上
で回転している場合でも、その受信信号が単独信号であ
る場合には、その振幅を見ることによって、どのシンボ
ル点に対応する受信信号であるかを知ることができる。
しかし、単独信号でない場合は、その振幅からでは対応
するシンボル点を判定することができない。As shown in FIG. 11, even when the reception signal point is rotating on the IQ plane, if the reception signal is a single signal, the amplitude corresponding to which reception point corresponds to the reception signal point. You can know if it is a signal.
However, if the signal is not a single signal, the corresponding symbol point cannot be determined from its amplitude.
【０００７】そこで、従来、受信キャリアと再生キャリ
アとの周波数差を求める場合は、受信信号がその振幅か
ら単独信号であると判別されたときに、再生キャリアの
位相を基準としてその信号の位相を記憶し、引き続き受
信した受信信号が単独信号であったときに、再び再生キ
ャリアの位相を基準としてその信号の位相を求め、先に
記憶した位相の値との差を取る。この差Δθが１シンボ
ル時間における位相の変化分である。従って、再生搬送
波と受信搬送波との周波数差Δｆは、ｔsymをシンボル
時間とすると、次の式によって求められる。Therefore, conventionally, when the frequency difference between the received carrier and the reproduced carrier is obtained, when the received signal is discriminated from the amplitude as a single signal, the phase of the reproduced carrier is used as a reference to determine the phase of the signal. When the received signal which is stored and continuously received is a single signal, the phase of the signal is again obtained with the phase of the reproduced carrier as a reference, and the difference from the previously stored phase value is taken. This difference Δθ is the change amount of the phase in one symbol time. Therefore, the frequency difference Δf between the reproduced carrier wave and the received carrier wave is obtained by the following equation, where t sym is the symbol time.
【０００８】Δｆ＝（１／２π）・（Δθ／ｔsym） 従来、このような周波数比較方法で再生キャリアと受信
キャリアとの周波数差を求めている。Δf = (1 / 2π) (Δθ / t sym ) Conventionally, the frequency difference between the reproduced carrier and the received carrier is obtained by such a frequency comparison method.
【０００９】[0009]
【発明が解決しようとする課題】しかし、従来の周波数
比較方法では、受信信号が２つ以上連続して単独信号で
なければ再生キャリアと受信キャリアとの周波数比較が
できないという問題点があった。例えば６４ＱＡＭの場
合、単独信号が２回連続する確率は、信号がランダムに
受信されると仮定すると９／２５６という小ささであ
り、充分な周波数比較利得が得られにくい。However, the conventional frequency comparison method has a problem that the frequency comparison between the reproduced carrier and the received carrier cannot be performed unless the received signals are two or more consecutive continuous signals. For example, in the case of 64QAM, the probability that a single signal will be transmitted twice consecutively is as small as 9/256 assuming that the signal is received randomly, and it is difficult to obtain a sufficient frequency comparison gain.
【００１０】本発明は、このような従来の問題点を解決
するものであり、単独信号が連続しないときでも再生キ
ャリアと受信キャリアとの周波数比較を行なうことがで
きる周波数比較方法を提供することを目的としている。The present invention solves such a conventional problem, and provides a frequency comparison method capable of performing frequency comparison between a reproduction carrier and a reception carrier even when a single signal is not continuous. Has an aim.
【００１１】[0011]
【課題を解決するための手段】そこで、本発明では、受
信直交振幅変調信号の復調に際して、受信搬送波と再生
搬送波との周波数差を求める周波数比較方法において、
第１の受信信号点がそれに対応する第１のシンボル点と
一致するようにＩＱ軸を回転させ、次に受信した第２の
受信信号点の原点からの距離とＩＱどちらかの軸からの
位相からその第２の受信信号点に対応する第２のシンボ
ル点を判定し、第２の受信信号点と原点と第２のシンボ
ル点とが成す角度と、信号を受信する時間間隔とから周
波数差を求めている。Therefore, in the present invention, in demodulating a reception quadrature amplitude modulation signal, in a frequency comparison method for obtaining a frequency difference between a reception carrier wave and a reproduction carrier wave,
The IQ axis is rotated so that the first received signal point coincides with the corresponding first symbol point, and the distance from the origin of the second received signal point received next and the phase from either axis of IQ. A second symbol point corresponding to the second received signal point is determined from the frequency difference from the angle formed by the second received signal point, the origin and the second symbol point, and the time interval for receiving the signal. Are seeking.
【００１２】また、第１の受信信号点の原点からの距離
が、少なくとも当初の周波数比較では、原点から等しい
距離にあるシンボル点が同一象限に１つしか存在しない
シンボル点の距離と一致するように、対象の受信信号を
選択している。Further, the distance of the first received signal point from the origin should be equal to the distance of the symbol points having the same distance from the origin at least in the same quadrant, at least in the initial frequency comparison. Then, the received signal of interest is selected.
【００１３】また、第１の受信信号点のＩＱ平面上の位
置を記憶しておき、次に受信した第２の受信信号点が、
原点からの距離の等しいシンボルが同一象限に１つしか
存在しないシンボルに対応しているとき、この第２の受
信信号点がそれに対応する第２のシンボル点となるよう
にＩＱ軸を回転させ、ＩＱ軸を回転させた後の第１の受
信信号点の位置からその受信信号点に対応する第１のシ
ンボル点を判定し、第１の受信信号点と原点と第１のシ
ンボル点とが成す角度と、受信信号の時間間隔とから周
波数差を求めている。The position of the first received signal point on the IQ plane is stored, and the second received signal point received next is
When the symbols having the same distance from the origin correspond to only one symbol in the same quadrant, the IQ axis is rotated so that this second received signal point becomes the corresponding second symbol point, From the position of the first received signal point after rotating the IQ axis, the first symbol point corresponding to the received signal point is determined, and the first received signal point, the origin, and the first symbol point are formed. The frequency difference is obtained from the angle and the time interval of the received signal.
【００１４】また、これらの第１及び第２の受信信号点
における原点からの距離が、予め設定した距離閾値以上
となるように、対象の受信信号を選択している。Further, the target reception signal is selected so that the distances from the origin at these first and second reception signal points are equal to or greater than a preset distance threshold.
【００１５】また、これらの第１及び第２の受信信号点
における原点からの距離が、原点から等しい距離にある
シンボル点の任意の２点と原点とを結ぶ線の成す角度が
いずれも予め設定した角閾値以上であるシンボル点の距
離と一致するように、対象の受信信号を選択している。Further, the angles formed by the lines connecting any two points of the symbol points having the same distance from the origin and the origin at the first and second reception signal points are set in advance. The target received signal is selected so as to match the distance of the symbol points that is equal to or greater than the above-mentioned angular threshold.
【００１６】また、得られた周波数差が、予め設定した
周波数閾値以下となったとき、この角閾値の値を小さく
している。Further, when the obtained frequency difference becomes less than or equal to a preset frequency threshold value, the value of this angular threshold value is reduced.
【００１７】[0017]
【作用】本発明では、受信キャリアと再生キャリアとの
周波数差を次のように求める。系がリセットされた直後
では、次々に受信する信号の振幅を監視し、この振幅に
基づいて単独信号を検出する。単独信号が検出されたと
きは、その位相と、単独信号に対応するシンボル点の位
相（６４ＱＡＭではπ／４）との差φaを求める。次の
信号を受信すると、その受信信号の位相をφaだけ回転
させ、回転後の信号点近くの同一振幅を有するシンボル
点を対応するシンボル点として判定し、受信信号点（回
転後の信号点）と、この対応するシンボル点とが原点を
挟んで成す角度θaを求め、その角度から周波数差を求
める。その次に受信した信号については、φa＋θaを新
たにφaとして、同じ方法で周波数差を求める。それ以
降の受信信号についても同様である。In the present invention, the frequency difference between the reception carrier and the reproduction carrier is obtained as follows. Immediately after the system is reset, the amplitude of the signals received one after another is monitored, and a single signal is detected based on this amplitude. When a single signal is detected, the difference φ a between the phase and the phase (π / 4 in 64QAM) of the symbol point corresponding to the single signal is obtained. When the next signal is received, the phase of the received signal is rotated by φ a, and the symbol points having the same amplitude near the rotated signal point are determined as the corresponding symbol points. ) And the corresponding symbol point sandwiching the origin, the angle θ a is obtained, and the frequency difference is obtained from the angle θ a . For the signal received next, φ a + θ a is newly set as φ a , and the frequency difference is obtained by the same method. The same applies to received signals thereafter.
【００１８】また、本発明では、次のような方法でもこ
の周波数差を求めている。信号を受信したとき、その振
幅と位相とを記憶し、次に受信した信号が単独信号であ
った場合に、その単独信号の位相と単独信号に対応する
シンボル点の位相（６４ＱＡＭではπ／４）との差φb
を求め、次いで、先に記憶した受信信号の位相をφbだ
け回転させ、その回転位置の信号点近くの同一振幅を有
するシンボル点を受信信号に対応するシンボル点として
判定する。そして、受信信号点（回転後の信号点）とそ
の対応するシンボル点とが原点を挟んでなす角度θbを
求め、その角度から周波数差を計算する。Further, in the present invention, this frequency difference is also obtained by the following method. When a signal is received, its amplitude and phase are stored. When the next received signal is a single signal, the phase of the single signal and the phase of the symbol point corresponding to the single signal (π / 4 in 64QAM). ) Difference φ b
Then, the phase of the previously stored received signal is rotated by φ b, and a symbol point having the same amplitude near the signal point at the rotation position is determined as a symbol point corresponding to the received signal. Then, an angle θ b formed by the received signal point (rotated signal point) and its corresponding symbol point sandwiching the origin is obtained, and the frequency difference is calculated from the angle.
【００１９】また、この周波数の比較に用いる受信信号
を、振幅の大きい信号だけに限定することによって、求
める周波数差の精度を高めることができる。Further, by limiting the received signal used for this frequency comparison to only the signal having a large amplitude, the accuracy of the required frequency difference can be improved.
【００２０】また、この周波数の比較に用いる受信信号
を、対応するシンボル点における最小位相差が大きい信
号だけに限定することによって、受信搬送波と再生搬送
波との周波数差が大きい場合でも、その周波数差を求め
ることが可能になる。Further, by limiting the received signal used for this frequency comparison to only the signal having a large minimum phase difference at the corresponding symbol points, even if the frequency difference between the received carrier and the reproduced carrier is large, the frequency difference is large. It becomes possible to ask.
【００２１】さらに、受信搬送波と再生搬送波との周波
数差が縮小した段階で、周波数の比較に用いる受信信号
の前記最小位相差による限定を外すことにより、周波数
比較利得を高めることができる。Further, when the frequency difference between the received carrier wave and the reproduced carrier wave is reduced, the frequency comparison gain can be increased by removing the limitation due to the minimum phase difference of the received signal used for frequency comparison.
【００２２】[0022]
（第１実施例）まず、第１実施例の周波数比較方法の原
理について図１を用いて説明する。この図でＩ’Ｑ’は
再生キャリアの位相を基準とした軸を表している。最初
に単独信号（ｉ，ｑ）31をその振幅（√（ｉ2＋ｑ2））
から見つけ、位相φ1（＝ｔａｎ-1（ｉ／ｑ））を計算
する。６４ＱＡＭの場合には、単独シンボルの位相は必
ずπ／４であるので、単独信号の受信信号点31の位相の
ずれの大きさθ1はθ1＝（π／４）−φ1として求めら
れる。このθ1はＩ’Ｑ’軸と受信キャリア位相を基準
としたＩＱ軸とのずれ角を表している。(First Embodiment) First, the principle of the frequency comparison method of the first embodiment will be described with reference to FIG. In this figure, I'Q 'represents the axis based on the phase of the reproduced carrier. First, the single signal (i, q) 31 is converted into its amplitude (√ (i 2 + q 2 )).
Then, the phase φ 1 (= tan −1 (i / q)) is calculated. In the case of 64QAM, since the phase of a single symbol is always π / 4, the phase shift magnitude θ 1 of the reception signal point 31 of a single signal is obtained as θ 1 = (π / 4) −φ 1. . This θ 1 represents a shift angle between the I′Q ′ axis and the IQ axis with reference to the received carrier phase.
【００２３】次に、受信信号点33の信号を受信したとす
ると、その信号点33の位相をさらにθ1だけ回転させた
信号点34の振幅と位相φ2とを求める。つまり、受信信
号点33の位相を、単独信号31で求めた位相ずれの大きさ
θ1だけ補正した点34を求めることになる。この受信信
号点34の振幅と位相とから、受信信号点34の近くにある
同一振幅のシンボル点35を、受信信号点34に対応するシ
ンボル点と定め、信号点34とシンボル点35との位相差θ
2を求める。このθ2は１シンボル時間（ｔsym）での位
相の変化量であるから、再生搬送波と受信搬送波との周
波数差Δｆは、 Δｆ＝（１／２π）・（θ2／ｔsym） として求めることができる。Next, assuming that the signal at the reception signal point 33 is received, the amplitude and phase φ 2 of the signal point 34 obtained by further rotating the phase of the signal point 33 by θ 1 are obtained. That is, the point 34 is obtained by correcting the phase of the reception signal point 33 by the magnitude θ 1 of the phase shift obtained by the single signal 31. From the amplitude and phase of the received signal point 34, the symbol point 35 having the same amplitude near the received signal point 34 is defined as the symbol point corresponding to the received signal point 34, and the position of the signal point 34 and the symbol point 35 is determined. Phase difference θ
Ask for 2 . Since θ 2 is the amount of change in phase in one symbol time (t sym ), the frequency difference Δf between the reproduced carrier wave and the received carrier wave is obtained as Δf = (1 / 2π) · (θ 2 / t sym ). be able to.
【００２４】こうした周波数比較方法を実施する装置
は、図２に示すように、検波後のＩ，Ｑの値であるＩda
ta、Ｑdataから受信信号の振幅を求める振幅判定回路21
と、Ｉdata、Ｑdataから受信信号の再生キャリアに対す
る位相を求める位相判定回路22と、位相判定回路22の値
を回転させる位相回転回路23と、振幅及び位相の値から
受信信号に対応するシンボルを判別するシンボル判別回
路24と、指定されたシンボルに対する受信信号の位相ず
れを検出する位相差検出回路25と、位相ずれの値から周
波数差を求める周波数差検出回路26とを備えている。As shown in FIG. 2, an apparatus for carrying out such a frequency comparison method has an Ida value which is a value of I and Q after detection.
Amplitude determination circuit 21 for obtaining the amplitude of the received signal from ta and Qdata
, A phase determination circuit 22 for obtaining the phase of the received signal with respect to the reproduced carrier from Idata and Qdata, a phase rotation circuit 23 for rotating the value of the phase determination circuit 22, and a symbol corresponding to the received signal from the amplitude and phase values. The symbol discriminating circuit 24, the phase difference detecting circuit 25 for detecting the phase shift of the received signal with respect to the designated symbol, and the frequency difference detecting circuit 26 for obtaining the frequency difference from the value of the phase shift.
【００２５】次に、この装置を用いて行なう第１実施例
の周波数比較方法を図１により説明する。前提として変
調形式は６４ＱＡＭ、信号伝送速度を１Ｍbaudとする。
また、信号を31、33の順で受信した場合を説明する。Next, the frequency comparison method of the first embodiment using this apparatus will be described with reference to FIG. As a premise, the modulation format is 64 QAM and the signal transmission rate is 1 Mbaud.
Further, a case where signals are received in the order of 31 and 33 will be described.
【００２６】受信信号点31の座標を（ｉ，ｑ）とする
と、振幅判定回路21は√（ｉ2＋ｑ2）の計算により受信
信号点31の振幅を求める。位相判定回路22はｔａｎ
-1（ｉ／ｑ）の計算によって受信信号点31の位相φ1を
求める。位相回転回路23は位相判定回路22の求めた値を
そのままシンボル判別回路24へ伝える。シンボル判別回
路24は、振幅判定回路21の値から受信信号31が単独信号
であると判断し、位相回転回路23の値にかかわらずその
旨を位相差検出回路25に通知する。位相差検出回路25
は、６４ＱＡＭの場合、単独シンボルの位相は必ずπ／
４であるので、受信信号点31の位相のずれの大きさθ1
を θ1＝（π／４）−φ1 の計算により求める。Assuming that the coordinates of the reception signal point 31 are (i, q), the amplitude judgment circuit 21 obtains the amplitude of the reception signal point 31 by calculating √ (i 2 + q 2 ). The phase determination circuit 22 is tan
The phase φ 1 of the reception signal point 31 is obtained by calculating −1 (i / q). The phase rotation circuit 23 transfers the value obtained by the phase determination circuit 22 to the symbol determination circuit 24 as it is. The symbol determination circuit 24 determines from the value of the amplitude determination circuit 21 that the received signal 31 is a single signal, and notifies the phase difference detection circuit 25 to that effect regardless of the value of the phase rotation circuit 23. Phase difference detection circuit 25
Is 64QAM, the phase of a single symbol is always π /
4, the magnitude of the phase shift of the received signal point 31 θ 1
Is calculated by calculating θ 1 = (π / 4) −φ 1 .
【００２７】ここで得られたθ1は位相回転回路23へ送
られる。The θ 1 obtained here is sent to the phase rotation circuit 23.
【００２８】次に、受信信号点33を受信すると、振幅判
定回路21はその振幅を計算し、計算結果をシンボル判別
回路24に出力し、また、位相判定回路22はその位相を求
め、位相回転回路23は、位相判定回路22の求めた位相を
θ1だけ回転させた値φ2を求めて、シンボル判別回路24
へ出力する。従って、シンボル判別回路24には受信信号
33が信号点34として入力されることになる。シンボル判
別回路24は、信号点34の振幅及び位相から、同一振幅を
有し位相の近似するシンボル点35が信号点34に対応する
シンボル点であると判別し、位相差検出回路25に通知す
る。Next, when the reception signal point 33 is received, the amplitude judgment circuit 21 calculates its amplitude, outputs the calculation result to the symbol judgment circuit 24, and the phase judgment circuit 22 obtains its phase and performs phase rotation. The circuit 23 obtains a value φ 2 obtained by rotating the phase obtained by the phase determination circuit 22 by θ 1 , and the symbol determination circuit 24
Output to. Therefore, the symbol discrimination circuit 24
33 will be input as the signal point 34. From the amplitude and phase of the signal point 34, the symbol determination circuit 24 determines that the symbol point 35 having the same amplitude and the approximate phase is the symbol point corresponding to the signal point 34, and notifies the phase difference detection circuit 25. .
【００２９】位相差検出回路25は、信号点34とシンボル
点35との位相差θ2を求め、それを周波数差検出回路26
と位相回転回路23とに出力する。周波数差検出回路26は
１シンボル時間で位相がθ2だけ変化したことから周波
数差Δｆを Δｆ＝（１／２π）・（θ2／１μｓ） ∴１Ｍbaudのシンボル時間は１μｓ として求める。一方、位相回転回路23は、次の受信信号
に対してはθ1＋θ2だけ位相を回転させる。以降の受信
信号に対しても同様な処理を行なう。The phase difference detection circuit 25 finds the phase difference θ 2 between the signal point 34 and the symbol point 35, and uses it to determine the frequency difference detection circuit 26.
And the phase rotation circuit 23. The frequency difference detection circuit 26 is 1 symbol time frequency difference Delta] f from the phase changes by θ 2 Δf = (1 / 2π ) · (θ 2 / 1μs) ∴1Mbaud symbol time of obtaining a 1 [mu] s. On the other hand, the phase rotation circuit 23 rotates the phase by θ 1 + θ 2 for the next received signal. Similar processing is performed for the subsequent received signals.
【００３０】このように、第１実施例の周波数比較方法
では、装置の初期化後、一旦単独信号を受信すれば、そ
の後はどのシンボル点に対応する信号を受信しても周波
数比較を行なうことができる。As described above, in the frequency comparison method of the first embodiment, after the initialization of the apparatus, once the single signal is received, the frequency comparison is performed regardless of the signal corresponding to any symbol point. You can
【００３１】なお、図３には、６４ＱＡＭの場合の同じ
振幅を持つシンボルにおける隣接シンボルとの間の位相
差を示している。シンボル判別回路24では、周波数差が
余りに大きく、そのため位相差θ2が隣接シンボルとの
位相差を超えてしまうときには、信号点34がシンボル点
35に対応するのか、同一振幅を有する隣のシンボル点に
対応するのかが判別できなくなる。６４ＱＡＭの場合、
この隣接シンボルとの間の位相差の最小値（最小位相
差）は図３に示すように１６．３°、約０．２８radな
ので、第１実施例の周波数比較方法では、 （１／２π）・（０．２８／２）／１μｓ≒２２．６ｋ
Ｈｚ までの周波数差を正しく検出することができる。FIG. 3 shows the phase difference between adjacent symbols in a symbol having the same amplitude in the case of 64QAM. In the symbol discrimination circuit 24, when the frequency difference is so large that the phase difference θ 2 exceeds the phase difference with the adjacent symbol, the signal point 34 becomes the symbol point.
It becomes impossible to determine whether it corresponds to 35 or a neighboring symbol point having the same amplitude. For 64QAM,
The minimum value (minimum phase difference) of the phase difference between the adjacent symbols is 16.3 °, which is about 0.28 rad, as shown in FIG. 3, so that in the frequency comparison method of the first embodiment, (1 / 2π)・ (0.28 / 2) / 1μs ≈ 22.6k
The frequency difference up to Hz can be detected correctly.
【００３２】（第２実施例）第２実施例の周波数比較方
法では、高精度の比較結果を得るために、比較対象に使
用する受信信号を、信号点の振幅が大きいものだけに限
定している。(Second Embodiment) In the frequency comparison method of the second embodiment, in order to obtain a highly accurate comparison result, the received signals used for comparison are limited to those having a large signal point amplitude. There is.
【００３３】この方法を実施する装置は、図４に示すよ
うに、予め定められた値より小さい振幅をもつ受信信号
を検出する振幅監視回路27を備えており、シンボル判別
回路28は、振幅監視回路27が検出した信号に対して周波
数比較動作を停止するリセット機能を備えている。その
他の構成は、第１実施例の装置（図２）と変わりがな
い。As shown in FIG. 4, the apparatus for carrying out this method is provided with an amplitude monitor circuit 27 for detecting a received signal having an amplitude smaller than a predetermined value, and the symbol discrimination circuit 28 has an amplitude monitor circuit. It has a reset function for stopping the frequency comparison operation with respect to the signal detected by the circuit 27. The other structure is the same as that of the device of the first embodiment (FIG. 2).
【００３４】図５は各シンボル点の座標を８bitで表し
た例である。数字についた「Ｈ」はその数字が１６進数
であることを示す。また円弧上に示した値は振幅の大き
さである。FIG. 5 shows an example in which the coordinates of each symbol point are represented by 8 bits. The "H" attached to a number indicates that the number is hexadecimal. The value shown on the arc is the magnitude of the amplitude.
【００３５】次に、第２実施例の周波数比較方法につい
て説明する。ここで振幅監視回路27は受信信号の振幅が
Ｅ８Ｈ以下の場合、シンボル判別回路28に対しリセット
信号を発生するものとする。本実施例の動作は基本的に
第１実施例と同じである。しかし、振幅がＥ８Ｈよりも
小さい信号を受信した場合は、振幅監視回路27がリセッ
ト信号をシンボル判別回路28に出力し、シンボル判別回
路28は周波数比較動作を停止して、状態を初期化する。
その後、振幅がＥ８Ｈ以上の単独信号を受信した時点で
再び周波数比較動作を開始する。Next, the frequency comparison method of the second embodiment will be described. Here, it is assumed that the amplitude monitor circuit 27 generates a reset signal to the symbol discrimination circuit 28 when the amplitude of the received signal is E8H or less. The operation of this embodiment is basically the same as that of the first embodiment. However, when a signal whose amplitude is smaller than E8H is received, the amplitude monitoring circuit 27 outputs a reset signal to the symbol discrimination circuit 28, and the symbol discrimination circuit 28 stops the frequency comparison operation and initializes the state.
After that, the frequency comparison operation is started again when a single signal having an amplitude of E8H or more is received.
【００３６】Ｉdata、Ｑdataがこの例で示したように８
bitに量子化されたものである場合、振幅の大きなシン
ボルと小さなシンボルとでは、表現できる位相の精度が
違ってくる。例えば、最も振幅の大きいシンボルと最も
振幅の小さいシンボルとでＩ’成分を１ＬＳＢだけ変化
した場合、それぞれの位相の変化は０．１１°及び０．
７８°である。従って、第２実施例のように、精度の低
いシンボルを周波数比較の対象から外すことによって、
比較結果の精度を上げることができる。Idata and Qdata are 8 as shown in this example.
When quantized into bits, the precision of the phase that can be expressed differs between a symbol with a large amplitude and a symbol with a small amplitude. For example, when the I ′ component is changed by 1 LSB between the symbol having the largest amplitude and the symbol having the smallest amplitude, the respective phase changes are 0.11 ° and 0.
It is 78 °. Therefore, as in the second embodiment, by excluding a symbol with low accuracy from the target of frequency comparison,
The accuracy of the comparison result can be improved.
【００３７】（第３実施例）第３実施例の周波数比較方
法では、隣接シンボル点との位相差が小さいシンボル点
に対応する可能性のある受信信号を周波数比較の対象か
ら除いている。図３及び図５から分かるように、６４Ｑ
ＡＭのシンボル点では、振幅がＦＦＨであるシンボル点
間の最小位相差が１６．３°である。このようにシンボ
ル点間の最小位相差が小さいと、第１実施例で説明した
ように、再生キャリアと受信キャリアとの周波数差が大
きい場合に、それらの周波数比較を行なうことができな
い。(Third Embodiment) In the frequency comparison method of the third embodiment, the received signal which may correspond to a symbol point having a small phase difference from the adjacent symbol point is excluded from the frequency comparison targets. As can be seen from FIGS. 3 and 5, 64Q
At the AM symbol point, the minimum phase difference between the symbol points whose amplitude is FFH is 16.3 °. If the minimum phase difference between the symbol points is small as described above, the frequency comparison between them cannot be performed when the frequency difference between the reproduction carrier and the reception carrier is large, as described in the first embodiment.
【００３８】この第３実施例の周波数比較方法を実施す
る装置では、図６に示すように、受信信号の振幅が予め
定められた、最小位相差の小さいシンボル点の振幅に一
致するかどうかを検出する振幅選別回路29を具備してお
り、シンボル判別回路28は、振幅選別回路29が検出した
受信信号に対して周波数比較動作を停止するリセット機
能を備えている。この装置のその他の構成は第１実施例
（図２）と変わりがない。In the apparatus for carrying out the frequency comparison method of the third embodiment, as shown in FIG. 6, it is determined whether or not the amplitude of the received signal coincides with the amplitude of a predetermined symbol point having a small minimum phase difference. The amplitude discriminating circuit 29 for detecting is provided, and the symbol discriminating circuit 28 has a reset function for stopping the frequency comparison operation for the received signal detected by the amplitude discriminating circuit 29. The other structure of this device is the same as that of the first embodiment (FIG. 2).
【００３９】次に、第３実施例の動作について説明す
る。ここで振幅選別回路29は、各シンボル点の振幅を図
５のように表したとき、受信信号の振幅が１３６Ｈ、Ｆ
ＦＨ、Ｂ８Ｈである場合に、シンボル判別回路28に対し
てリセット信号を発生するように予め定められている。
この振幅が１３６Ｈ、ＦＦＨ、Ｂ８Ｈであるシンボルの
最小位相差は、図３に示すように、それぞれ１８．９
°、１６．３°、２２．６°と小さい。Next, the operation of the third embodiment will be described. Here, when the amplitude selection circuit 29 represents the amplitude of each symbol point as shown in FIG. 5, the amplitude of the received signal is 136H, F.
In the case of FH and B8H, it is predetermined to generate a reset signal to the symbol discrimination circuit 28.
The minimum phase difference of the symbols having the amplitudes of 136H, FFH, and B8H is 18.9, as shown in FIG.
°, 16.3 ° and 22.6 °, which are small.
【００４０】本実施例の動作は基本的に第１実施例と同
じである。しかし、振幅が先に示した値を持つ信号を受
信した場合は、振幅選別回路29がそれを検出してシンボ
ル判別回路28にリセット信号を出力し、シンボル判別回
路28は、周波数比較動作を停止して、状態を初期化す
る。その後、単独信号を受信した時点で再び周波数比較
動作を開始する。The operation of this embodiment is basically the same as that of the first embodiment. However, when the signal having the amplitude shown above is received, the amplitude selection circuit 29 detects it and outputs a reset signal to the symbol determination circuit 28, and the symbol determination circuit 28 stops the frequency comparison operation. Then, the state is initialized. After that, when the single signal is received, the frequency comparison operation is started again.
【００４１】図３で明らかなように各シンボル点をその
振幅毎に見た場合、振幅の値によって最小位相差が異な
る。従って、最小位相差の大きいシンボルのみを対象と
することによって比較可能周波数範囲を広くすることが
できる。第３実施例の周波数比較方法では、振幅が１３
６Ｈ、ＦＦＨ、Ｂ８Ｈの受信信号を対象から除くことに
よって、最小位相差が２８．１°（≒０．４９rad）と
なるので、比較可能周波数範囲は、 （１／２π）・（０．４９／２）／１μｓ≒ ３９ｋＨ
ｚ となる。これは第１実施例での比較可能周波数範囲より
広い。As is apparent from FIG. 3, when each symbol point is viewed for each amplitude, the minimum phase difference differs depending on the amplitude value. Therefore, it is possible to widen the comparable frequency range by targeting only the symbols having a large minimum phase difference. In the frequency comparison method of the third embodiment, the amplitude is 13
By excluding the received signals of 6H, FFH, and B8H from the target, the minimum phase difference becomes 28.1 ° (≈0.49rad), so the comparable frequency range is (1 / 2π) · (0.49 / 2) / 1 μs ≈ 39 kHz
z. This is wider than the comparable frequency range in the first embodiment.
【００４２】（第４実施例）第４実施例の周波数比較方
法では、第３実施例と同様に、最小位相差の小さいシン
ボルと同じ振幅をもつ受信信号を周波数比較の対象から
除外するが、再生キャリアと受信キャリアとの周波数差
が縮まった段階でこの除外を停止する。(Fourth Embodiment) In the frequency comparison method of the fourth embodiment, similarly to the third embodiment, the received signal having the same amplitude as the symbol having the smallest minimum phase difference is excluded from the frequency comparison targets. This exclusion is stopped when the frequency difference between the reproduction carrier and the reception carrier is reduced.
【００４３】この方法を実施する装置は、図７に示すよ
うに、位相差検出回路25の出力値が小さくなると受信信
号の選別を停止する振幅選別回路30を備えている。その
他の構成は第３実施例の装置（図６）と同じである。As shown in FIG. 7, the apparatus for carrying out this method is provided with an amplitude selection circuit 30 which stops the selection of received signals when the output value of the phase difference detection circuit 25 becomes small. The other structure is the same as that of the device of the third embodiment (FIG. 6).
【００４４】次に第４実施例の動作について説明する。
本実施例の動作は基本的に第３実施例と同じである。し
かし、周波数差が縮まり、位相差検出回路25の出力値が
予め定められた値より小さくなると、振幅選別回路30は
受信信号の選別を停止し、それによりシンボル判別回路
28はすべての受信信号を判別の対象にする。Next, the operation of the fourth embodiment will be described.
The operation of this embodiment is basically the same as that of the third embodiment. However, when the frequency difference is reduced and the output value of the phase difference detection circuit 25 becomes smaller than a predetermined value, the amplitude selection circuit 30 stops the selection of the received signal, thereby causing the symbol determination circuit.
In 28, all received signals are targets for discrimination.
【００４５】第３実施例で明らかなように、受信信号を
振幅によって選別すれば比較可能周波数範囲は広がる
が、比較に使用できるシンボル数が減少するため周波数
比較利得が小さくなるという問題点がある。しかし、本
実施例では周波数差が小さくなった時点ですべての受信
信号を用いて比較動作を行なうようにするので周波数比
較利得は第１実施例と同じように大きくできるという利
点を有する。As is apparent from the third embodiment, if the received signal is selected according to the amplitude, the frequency range for comparison can be widened, but the number of symbols that can be used for comparison is reduced, so that the frequency comparison gain is reduced. . However, in this embodiment, since the comparison operation is performed using all the received signals when the frequency difference becomes small, the frequency comparison gain can be increased as in the first embodiment.
【００４６】（第５実施例）第５実施例の周波数比較方
法では、受信した単独信号とその前に受信した信号とか
ら周波数差を求めている。(Fifth Embodiment) In the frequency comparison method of the fifth embodiment, the frequency difference is obtained from the received single signal and the signal received before that.
【００４７】この周波数比較方法を実施する装置は、図
８に示すように、受信信号の振幅からそれが単独信号で
あるかどうかを検出し、単独信号である場合に出力をア
クティブにする単独信号検出回路81と、単独信号検出回
路81が単独信号を検出したときに位相判定回路22の示す
位相とπ／４との差を求める位相差算出回路82と、振幅
判定回路21及び位相判定回路22の出力値を一旦蓄えるレ
ジスタ83とを備えている。その他の構成は第１実施例の
装置（図２）と変わりがない。As shown in FIG. 8, the device for carrying out this frequency comparison method detects from the amplitude of the received signal whether or not it is a single signal, and when it is a single signal, an independent signal which activates the output. The detection circuit 81, a phase difference calculation circuit 82 for obtaining the difference between the phase indicated by the phase determination circuit 22 and π / 4 when the single signal detection circuit 81 detects a single signal, the amplitude determination circuit 21, and the phase determination circuit 22. And a register 83 for temporarily storing the output value of. The other structure is the same as that of the apparatus of the first embodiment (FIG. 2).
【００４８】次に第５実施例の動作について説明する。
信号を受信すると、振幅判定回路21及び位相判定回路22
はその振幅と位相とを求め、それらの値をレジスタ83に
蓄える。次に受信した信号が単独信号であるときは、単
独信号検出回路81は、それを検出して出力をアクティブ
にし、位相差算出回路82は、それを受けて、位相判定回
路22の求めた単独信号の位相とπ／４との位相差を計算
し、その値を位相回転回路23に送る。位相回転回路23は
レジスタ83に蓄えられた位相を位相判定回路22から送ら
れた位相差だけ回転し、その値をシンボル判別回路28及
び位相差検出回路25に出力する。Next, the operation of the fifth embodiment will be described.
When the signal is received, the amplitude determination circuit 21 and the phase determination circuit 22
Calculates its amplitude and phase, and stores those values in the register 83. When the next received signal is a single signal, the single signal detection circuit 81 detects it and activates the output, and the phase difference calculation circuit 82 receives it and outputs the single signal determined by the phase determination circuit 22. The phase difference between the signal phase and π / 4 is calculated and the value is sent to the phase rotation circuit 23. The phase rotation circuit 23 rotates the phase stored in the register 83 by the phase difference sent from the phase determination circuit 22, and outputs the value to the symbol determination circuit 28 and the phase difference detection circuit 25.
【００４９】シンボル判別回路28は、単独信号検出回路
81が単独信号を検出したことを受けて、位相回転回路23
から送られた位相とレジスタ83から読み出した振幅とを
持つ信号点の近傍に位置する同一振幅のシンボル点を、
対応するシンボル点として判別し、位相差検出回路25
は、そのシンボル点の位相と位相回転回路23から送られ
た位相との位相差を算出し、周波数差検出回路26はその
位相差を基に周波数差を計算する。このシンボル判別回
路28、位相差検出回路25及び周波数差検出回路26の動作
は第１実施例と同じである。The symbol discrimination circuit 28 is a single signal detection circuit.
In response to the detection of the independent signal by 81, the phase rotation circuit 23
From the signal point having the phase sent from and the amplitude read from the register 83, the symbol point of the same amplitude,
Phase difference detection circuit 25
Calculates the phase difference between the phase of the symbol point and the phase sent from the phase rotation circuit 23, and the frequency difference detection circuit 26 calculates the frequency difference based on the phase difference. The operations of the symbol discrimination circuit 28, the phase difference detection circuit 25 and the frequency difference detection circuit 26 are the same as those in the first embodiment.
【００５０】このように第５実施例の周波数比較方法で
は、単独信号の一つ前に受信した信号を周波数比較に用
いることができる。従って、単独信号の受信後、次の信
号の受信を待って周波数比較を行なう場合よりも、迅速
に周波数比較を実行することができる。As described above, in the frequency comparison method of the fifth embodiment, the signal received immediately before the single signal can be used for frequency comparison. Therefore, after receiving the single signal, the frequency comparison can be performed more quickly than in the case where the frequency comparison is performed after waiting for the reception of the next signal.
【００５１】（第６実施例）第６実施例の周波数比較方
法では、第５実施例の方法の実施に当たって、比較対象
に使用する受信信号を振幅の大きいものだけに限定して
いる。(Sixth Embodiment) In the frequency comparison method of the sixth embodiment, in carrying out the method of the fifth embodiment, the received signals used for comparison are limited to those having a large amplitude.
【００５２】この方法を実施する装置は、図９に示すよ
うに、受信信号の振幅を監視し、振幅が所定値より小さ
きときに単独信号検出回路84及びレジスタ85に対してリ
セット信号を出力する振幅監視回路27を備えており、ま
た、単独信号検出回路84及びレジスタ85はリセット機能
を具備している。その他の構成は第５実施例の装置（図
８）と変わりがない。As shown in FIG. 9, the apparatus for carrying out this method monitors the amplitude of the received signal and outputs a reset signal to the individual signal detection circuit 84 and the register 85 when the amplitude is smaller than a predetermined value. The amplitude monitor circuit 27 is provided, and the single signal detection circuit 84 and the register 85 have a reset function. The other structure is the same as that of the device of the fifth embodiment (FIG. 8).
【００５３】本実施例の動作は基本的に第５実施例と同
じである。しかし、第２実施例と同じように、受信信号
の振幅がＥ８Ｈよりも小さい場合に、振幅監視回路27が
単独信号検出回路84及びレジスタ85に対してリセット信
号を発生し、周波数比較動作を停止する。The operation of this embodiment is basically the same as that of the fifth embodiment. However, like the second embodiment, when the amplitude of the received signal is smaller than E8H, the amplitude monitoring circuit 27 generates a reset signal to the individual signal detection circuit 84 and the register 85, and stops the frequency comparison operation. To do.
【００５４】この周波数比較方法では、第２実施例と同
じように、比較結果の精度を高めることができる。With this frequency comparison method, the accuracy of the comparison result can be increased, as in the second embodiment.
【００５５】（第７実施例）第７実施例の周波数比較方
法では、第５実施例の方法の実施に当たって、最小位相
差の小さいシンボルと振幅が一致する受信信号を比較対
象から除いている。この方法を実施する装置は、図１０
に示すように、予め定められた、最小位相差の小さいシ
ンボル点と同じ振幅をもつ受信信号を検出する振幅選別
回路29を備えている。振幅選別回路29は所定振幅の信号
を検出すると単独信号検出回路84及びレジスタ85に対し
てリセット信号を出力する。(Seventh Embodiment) In the frequency comparison method of the seventh embodiment, when the method of the fifth embodiment is executed, the received signal whose amplitude matches the symbol having the smallest minimum phase difference is excluded from the comparison object. An apparatus for carrying out this method is shown in FIG.
As shown in (1), an amplitude selection circuit 29 for detecting a reception signal having the same amplitude as a predetermined symbol point having a small minimum phase difference is provided. When the amplitude selection circuit 29 detects a signal of a predetermined amplitude, it outputs a reset signal to the single signal detection circuit 84 and the register 85.
【００５６】本実施例の動作は基本的に第５実施例と同
じである。しかし、第３実施例と同じように、受信信号
の振幅が１３６Ｈ、ＦＦＨ、Ｂ８Ｈである場合に、振幅
選別回路29は位相差算出回路84及びレジスタ85に対して
リセット信号を発生し、これによって比較動作が停止さ
れる。The operation of this embodiment is basically the same as that of the fifth embodiment. However, as in the third embodiment, when the amplitude of the received signal is 136H, FFH, B8H, the amplitude selection circuit 29 generates a reset signal to the phase difference calculation circuit 84 and the register 85, which causes The comparison operation is stopped.
【００５７】この周波数比較方法では、第３実施例と同
様、周波数比較範囲を広くすることができる。In this frequency comparison method, the frequency comparison range can be widened as in the third embodiment.
【００５８】[0058]
【発明の効果】以上の実施例の説明から明らかなよう
に、本発明の周波数比較方法は、受信した単独信号とそ
の前または後の受信信号とを用いて受信キャリアと再生
キャリアとの周波数差を求めることができる。そのた
め、単独信号の連続受信を待つ必要がなく、周波数比較
を迅速に行なうことができる。As is apparent from the above description of the embodiments, the frequency comparison method of the present invention uses the received single signal and the received signal before or after the received signal to detect the frequency difference between the received carrier and the regenerated carrier. Can be asked. Therefore, it is not necessary to wait for continuous reception of a single signal, and frequency comparison can be performed quickly.
【００５９】また、比較対象の受信信号を、振幅の大き
いものだけに限定することにより、高精度の周波数差を
得ることができ、また、比較対象の受信信号を、同一振
幅を有するシンボル間の最小位相差が大きいシンボルに
対応する信号だけに限定することにより、比較周波数範
囲を広げることができる。Further, by limiting the received signals to be compared only to those having a large amplitude, it is possible to obtain a highly accurate frequency difference, and the received signals to be compared can be obtained between symbols having the same amplitude. The comparison frequency range can be widened by limiting to only the signals corresponding to the symbols having a large minimum phase difference.
【図１】本発明の第１実施例における周波数比較方法の
動作説明図、FIG. 1 is an operation explanatory diagram of a frequency comparison method according to a first embodiment of the present invention,
【図２】第１実施例の周波数比較方法を実施する装置の
構成図、FIG. 2 is a block diagram of an apparatus for carrying out the frequency comparison method of the first embodiment,
【図３】６４ＱＡＭの各シンボル点の位相差を示す図FIG. 3 is a diagram showing a phase difference at each symbol point of 64QAM.
【図４】本発明の第２実施例における周波数比較方法を
実施する装置の構成図、FIG. 4 is a configuration diagram of an apparatus for performing a frequency comparison method according to a second embodiment of the present invention,
【図５】６４ＱＡＭの各シンボル点の振幅を示す図、FIG. 5 is a diagram showing the amplitude of each symbol point of 64QAM,
【図６】本発明の第３実施例における周波数比較方法を
実施する装置の構成図、FIG. 6 is a configuration diagram of an apparatus for performing a frequency comparison method according to a third embodiment of the present invention,
【図７】本発明の第４実施例における周波数比較方法を
実施する装置の構成図、FIG. 7 is a block diagram of an apparatus for carrying out a frequency comparison method according to a fourth embodiment of the present invention,
【図８】本発明の第５実施例における周波数比較方法を
実施する装置の構成図、FIG. 8 is a block diagram of an apparatus for carrying out a frequency comparison method according to a fifth embodiment of the present invention,
【図９】本発明の第６実施例における周波数比較方法を
実施する装置の構成図、FIG. 9 is a block diagram of an apparatus for performing a frequency comparison method according to a sixth embodiment of the present invention,
【図１０】本発明の第７実施例における周波数比較方法
を実施する装置の構成図、FIG. 10 is a block diagram of an apparatus for carrying out a frequency comparison method according to a seventh embodiment of the present invention,
【図１１】受信信号点の遷移を示す図である。FIG. 11 is a diagram showing transitions of received signal points.
21 振幅判定回路 22 位相判定回路 23 位相回転回路 24、28 シンボル判別回路 25 位相差検出回路 26 周波数差検出回路 27 振幅監視回路 29、30 振幅選別回路 81、84 単独信号検出回路 82 位相差算出回路 83、85 レジスタ 21 Amplitude determination circuit 22 Phase determination circuit 23 Phase rotation circuit 24, 28 Symbol determination circuit 25 Phase difference detection circuit 26 Frequency difference detection circuit 27 Amplitude monitoring circuit 29, 30 Amplitude selection circuit 81, 84 Single signal detection circuit 82 Phase difference calculation circuit 83, 85 registers
Claims (6)
受信搬送波と再生搬送波との周波数差を求める周波数比
較方法において、 第１の受信信号点がそれに対応する第１のシンボル点と
一致するようにＩＱ軸を回転させ、 次に受信した第２の受信信号点の原点からの距離とＩＱ
どちらかの軸からの位相からその第２の受信信号点に対
応する第２のシンボル点を判定し、 前記第２の受信信号点と原点と前記第２のシンボル点と
が成す角度と、信号を受信する時間間隔とから前記周波
数差を求めることを特徴とする周波数比較方法。1. When demodulating a received quadrature amplitude modulation signal,
In a frequency comparison method for obtaining a frequency difference between a received carrier wave and a reproduced carrier wave, the IQ axis is rotated so that the first received signal point coincides with the corresponding first symbol point, and then the second received signal is received. IQ from the origin of signal point
A second symbol point corresponding to the second received signal point is determined from the phase from either axis, and the angle formed by the second received signal point, the origin, and the second symbol point, and the signal A frequency comparison method, wherein the frequency difference is obtained from a time interval for receiving the.
が、少なくとも当初の周波数比較では、原点から等しい
距離にあるシンボル点が同一象限に１つしか存在しない
シンボル点の前記距離と一致するように、対象の受信信
号を選択することを特徴とする請求項１に記載の周波数
比較方法。2. The distance of the first received signal point from the origin coincides with the distance of a symbol point having at least one symbol point in the same quadrant at the same distance from the origin, at least in the initial frequency comparison. The frequency comparison method according to claim 1, wherein the target reception signal is selected so as to:
受信搬送波と再生搬送波との周波数差を求める周波数比
較方法において、 第１の受信信号点のＩＱ平面上の位置を記憶しておき、 次に受信した第２の受信信号点が、原点からの距離の等
しいシンボルが同一象限に１つしか存在しないシンボル
に対応しているとき、この第２の受信信号点が それに対応する第２のシンボル点となるようにＩＱ軸を
回転させ、 ＩＱ軸を回転させた後の前記第１の受信信号点の位置か
ら前記受信信号点に対応する第１のシンボル点を判定
し、 前記第１の受信信号点と原点と前記第１のシンボル点と
が成す角度と、受信信号の時間間隔とから前記周波数差
を求めることを特徴とする周波数比較方法。3. When demodulating a reception quadrature amplitude modulation signal,
In the frequency comparison method for obtaining the frequency difference between the received carrier wave and the reproduced carrier wave, the position of the first received signal point on the IQ plane is stored, and the second received signal point received next is the distance from the origin. When the symbols having the same number of 1 correspond to the symbols which exist only in the same quadrant, the IQ axis is rotated so that this second received signal point becomes the corresponding second symbol point, and the IQ axis is rotated. The first symbol point corresponding to the received signal point is determined from the position of the first received signal point after the operation, and the angle formed by the first received signal point, the origin, and the first symbol point. And the time difference between the received signals, the frequency difference is obtained from the frequency comparison method.
原点からの距離が、予め設定した距離閾値以上となるよ
うに、対象の受信信号を選択することを特徴とする請求
項１、２または３に記載の周波数比較方法。4. The target reception signal is selected such that the distances from the origin at the first and second reception signal points are equal to or greater than a preset distance threshold. Or the frequency comparison method described in 3.
原点からの距離が、原点から等しい距離にあるシンボル
点の任意の２点と原点とを結ぶ線の成す角度がいずれも
予め設定した角閾値以上であるシンボル点の前記距離と
一致するように、対象の受信信号を選択することを特徴
とする請求項１、２または３に記載の周波数比較方法。5. The distances from the origin at the first and second reception signal points are both preset by an angle formed by a line connecting any two of the symbol points at the same distance from the origin and the origin. 4. The frequency comparison method according to claim 1, 2 or 3, wherein the target reception signal is selected so as to match the distance of the symbol points that is equal to or greater than the angular threshold.
周波数閾値以下となったとき、前記角閾値の値を小さく
することを特徴とする請求項５に記載の周波数比較方
法。6. The frequency comparison method according to claim 5, wherein the value of the angular threshold value is reduced when the obtained frequency difference is equal to or less than a preset frequency threshold value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15275095A JP3324905B2 (en) | 1995-05-29 | 1995-05-29 | Frequency comparison method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15275095A JP3324905B2 (en) | 1995-05-29 | 1995-05-29 | Frequency comparison method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08331195A true JPH08331195A (en) | 1996-12-13 |
| JP3324905B2 JP3324905B2 (en) | 2002-09-17 |
Family
ID=15547352
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15275095A Expired - Fee Related JP3324905B2 (en) | 1995-05-29 | 1995-05-29 | Frequency comparison method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3324905B2 (en) |
-
1995
- 1995-05-29 JP JP15275095A patent/JP3324905B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP3324905B2 (en) | 2002-09-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP2731722B2 (en) | Clock frequency automatic control system and transmitter and receiver used therefor | |
| EP0688483B1 (en) | A digital communication system and a receiver for use in such a system | |
| JP3455934B2 (en) | Modulator | |
| CN103547344A (en) | Method, device and receiver for cycle slip | |
| EP1043873B1 (en) | Synchronization acquiring circuit | |
| JP4814017B2 (en) | Modulation method identification device | |
| US6175600B1 (en) | System for detecting the presence of a digital signal carrier wave, and a receiver including such a system | |
| JP2773562B2 (en) | Signal sequence detection method | |
| JPH08331195A (en) | Frequency comparison method | |
| EP1112634A1 (en) | Carrier frequency estimator for a signal receiver | |
| US7738599B2 (en) | Method and circuit for generating an auxiliary symbol for adjusting a QAM demodulator | |
| JP3148090B2 (en) | OFDM signal synchronous demodulator | |
| JP2885052B2 (en) | Automatic frequency control device | |
| JPH09238173A (en) | Method and device for synchronizing frequency | |
| JPH07154383A (en) | Frame synchronization detection circuit | |
| US6377639B1 (en) | Method, system, and apparatus for unambiguous phase synchronization | |
| JPH11331299A (en) | 64qam, 256qam modulation analysis method | |
| JPH09214569A (en) | Fsk base band demodulation device and moving body communication system | |
| JP3577301B2 (en) | Burst wave detector | |
| KR100209659B1 (en) | Digital phase-frequency detector of carrier recovery | |
| JPH07212423A (en) | Data receiver | |
| JP3409014B2 (en) | Modem device, image communication device, and communication control method | |
| JP3086144B2 (en) | Burst demodulator | |
| JP2000151545A (en) | Demodulator, demodulation method and provision medium | |
| JP4546372B2 (en) | Reception device, transmission system, and reception method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |