JPH04266243A - Fsk signal receiver - Google Patents
Fsk signal receiverInfo
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- JPH04266243A JPH04266243A JP2705691A JP2705691A JPH04266243A JP H04266243 A JPH04266243 A JP H04266243A JP 2705691 A JP2705691 A JP 2705691A JP 2705691 A JP2705691 A JP 2705691A JP H04266243 A JPH04266243 A JP H04266243A
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- fsk
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- 239000003990 capacitor Substances 0.000 claims abstract description 4
- 230000010355 oscillation Effects 0.000 claims description 20
- 230000010363 phase shift Effects 0.000 claims description 6
- 238000001914 filtration Methods 0.000 claims description 5
- 238000005728 strengthening Methods 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 11
- 230000002238 attenuated effect Effects 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000006073 displacement reaction Methods 0.000 description 2
- 230000002708 enhancing effect Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000011045 prefiltration Methods 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 235000014366 other mixer Nutrition 0.000 description 1
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Abstract
Description
【０００１】0001
【産業上の利用分野】本発明はＦＳＫ（Ｆｒｅｑｕｅｎ
ｃｙ Ｓｈｉｆｔ Ｋｅｙｉｎｇ， 周波数偏位変調）
信号を直接ベースバンド信号に復調するＦＳＫ信号受信
機に関する。[Industrial Application Field] The present invention is directed to FSK (Frequency
cy Shift Keying, Frequency Shift Keying)
The present invention relates to an FSK signal receiver that directly demodulates a signal into a baseband signal.
【０００２】0002
【従来の技術】図３は従来のＦＳＫ信号受信機の一般的
な構成を示すブロック図である。2. Description of the Related Art FIG. 3 is a block diagram showing the general configuration of a conventional FSK signal receiver.
【０００３】この従来のＦＳＫ信号受信機は、アンテナ
１に受信される１つの受信ＦＳＫ信号を高周波増幅器２
で所定レベルで増幅してから分岐して一対のミキサ回路
５， ６に与えるとともに、このミキサ回路５， ６の
一方には前記ＦＳＫ信号の搬送周波数にほぼ等しい周波
数の局部発振信号を局部発振回路３から与え、更に他方
には移相回路４によりπ／２相当の位相差を与えた局部
発振信号を入力する。This conventional FSK signal receiver transmits one received FSK signal received by an antenna 1 to a high frequency amplifier 2.
The signal is amplified to a predetermined level by the FSK signal, and then branched and applied to a pair of mixer circuits 5 and 6, and one of the mixer circuits 5 and 6 receives a local oscillation signal having a frequency approximately equal to the carrier frequency of the FSK signal. 3, and a local oscillation signal to which a phase difference equivalent to π/2 is given by a phase shift circuit 4 is input to the other side.
【０００４】この一対のミキサ回路５， ６の各出力信
号のＦＳＫ復調信号波はフィルタ部を通過し、不要な周
波数成分が減衰される。The FSK demodulated signal waves of the output signals of the pair of mixer circuits 5 and 6 pass through a filter section, and unnecessary frequency components are attenuated.
【０００５】このフィルタ部は、プレフィルタ７， ８
とジャイレータフィルタ９， １０により構成される。[0005] This filter section includes pre-filters 7 and 8
and gyrator filters 9 and 10.
【０００６】更に、ジャイレータフィルタ９， １０の
後段にはその出力信号をそれぞれ増幅する低周波増幅器
１１， １２が設けられる。Furthermore, low frequency amplifiers 11 and 12 are provided downstream of the gyrator filters 9 and 10 to amplify their output signals, respectively.
【０００７】この低周波増幅器１１， １２の出力信号
を振幅制限回路１３， １４により一定振幅に制限しつ
つ比較回路１５に与える。The output signals of the low frequency amplifiers 11 and 12 are applied to a comparison circuit 15 while being limited to a constant amplitude by amplitude limiting circuits 13 and 14.
【０００８】ここで、比較回路１５は、後述する方法に
より上記２つの入力信号を比較し、その比較結果に基づ
いて受信ＦＳＫ信号を復調することができる。[0008] Here, the comparison circuit 15 can compare the above two input signals by a method to be described later, and demodulate the received FSK signal based on the comparison result.
【０００９】このような受信機は、ＦＳＫ信号を直接ベ
ースバンド信号に復調することからダイレクトコンバー
ジョン受信機とも呼ばれる。[0009] Such a receiver is also called a direct conversion receiver because it demodulates the FSK signal directly into a baseband signal.
【００１０】ダイレクトコンバージョン受信機は、スー
パーヘテロダイン方式の受信機と違って中間周波数帯の
増幅器やろ波器が不要であり、受信機が小型化されると
ともに集積化が可能な装置として注目されている。Unlike superheterodyne type receivers, direct conversion receivers do not require intermediate frequency band amplifiers or filters, and are attracting attention as devices that can be miniaturized and integrated. .
【００１１】この受信機の動作を簡単に説明する。The operation of this receiver will be briefly explained.
【００１２】受信ＦＳＫ信号の搬送波周波数をｆｃ と
し、２値ＦＳＫ信号の周波数変位をδとすると、局部発
振周波数ｆｌ を搬送波周波数ｆｃ に等しくすること
により、ミキサ回路５， ６の出力には、その基本周波
数の信号として、周波数変位δに等しいベースバンド信
号が得られる。When the carrier frequency of the received FSK signal is fc and the frequency displacement of the binary FSK signal is δ, by making the local oscillation frequency fl equal to the carrier frequency fc, the outputs of the mixer circuits 5 and 6 have the following values: A baseband signal equal to the frequency displacement δ is obtained as a signal at the fundamental frequency.
【００１３】この基本周波数の信号をフィルタ７， ９
および８， １０で抽出する。[0013] This fundamental frequency signal is passed through filters 7 and 9.
and extract at 8 and 10.
【００１４】ここで二つのミキサ回路５および６に入力
する局部発振信号にπ／２の位相差を与えておくと、一
方のミキサ回路の基本周波数の出力信号をａ（ ｔ）ｃ
ｏｓ（２πδｔ）
とする時、他方のミキサ回路の基本周波数の出力信号は
ａ（ ｔ）ｃｏｓ（２πδｔ ＋２／π） ＝−ａ（
ｔ）ｓｉｎ（２πδｔ）
となって、フィルタ７， ９とフィルタ８， １０の出
力には相互にπ／２の位相差のある信号が得られる。Here, if a phase difference of π/2 is given to the local oscillation signals input to the two mixer circuits 5 and 6, the output signal of the fundamental frequency of one mixer circuit becomes a(t)c
os(2πδt), the output signal of the fundamental frequency of the other mixer circuit is a(t) cos(2πδt +2/π) = −a(
t) sin(2πδt), and signals having a phase difference of π/2 are obtained between the outputs of the filters 7 and 9 and the outputs of the filters 8 and 10.
【００１５】ここで、ａ（ ｔ） は、受信機の入力電
圧、高周波増幅器２、ミキサ回路５， ６及びフィルタ
７， ８， ９， １０の特性により決定されるフィル
タ９， １０の出力振幅を示している。Here, a(t) is the output amplitude of the filters 9 and 10 determined by the input voltage of the receiver, the high frequency amplifier 2, the mixer circuits 5 and 6, and the characteristics of the filters 7, 8, 9, and 10. It shows.
【００１６】すなわち、受信ＦＳＫ信号の周波数スペク
トラムが図４の通りである時、受信ＦＳＫ信号の周波数
偏移δの正負に応じて、比較回路１５の入力ＩおよびＱ
には図５または図６の信号が現れる。That is, when the frequency spectrum of the received FSK signal is as shown in FIG. 4, the inputs I and Q of the comparator circuit 15 are
The signal shown in FIG. 5 or 6 appears.
【００１７】つまり、入力ＩおよびＱのいずれかが進み
位相（遅れ位相）であるかを検出することによって、受
信ＦＳＫ信号の周波数偏移の＋δと−δを識別できる。That is, by detecting whether one of the inputs I and Q has a leading phase (lag phase), +δ and -δ of the frequency deviation of the received FSK signal can be identified.
【００１８】上記比較回路１５は、Ｄフリップフロップ
またはＪＫフリップフロップで簡単に実現でき、しかも
近年の技術により、送信装置は搬送波周波数ｆｃ のた
めの発振回路および局部発振回路として安定な回路が簡
単に得られるので、この装置はその構成が極めて簡単に
なる利点がある。The comparator circuit 15 can be easily realized using a D flip-flop or a JK flip-flop, and with recent technology, the transmitting device can easily be made into a stable circuit as an oscillation circuit and a local oscillation circuit for the carrier frequency fc. Therefore, this device has the advantage that its construction is extremely simple.
【００１９】このようにダイレクトコンバージョン受信
機では、位相がπ／２だけ異なる２つの信号を生成する
ためにミキサ回路５， ６を利用している。As described above, the direct conversion receiver uses mixer circuits 5 and 6 to generate two signals whose phases differ by π/2.
【００２０】このミキサ回路５， ６で生成した信号は
、後段のフィルタ部によって希望の周波数信号成分のみ
が抽出される。From the signals generated by the mixer circuits 5 and 6, only desired frequency signal components are extracted by a subsequent filter section.
【００２１】この時、フィルタ部では、まずプレフィル
タ７， ８がミキサ回路５， ６の出力信号に対する周
波数制限を行う。At this time, in the filter section, prefilters 7 and 8 first limit the frequency of the output signals of mixer circuits 5 and 6.
【００２２】次に、ジャイレータフィルタ９， １０は
更にその出力信号に対して周波数制限を行い、隣接周波
数信号成分を完全に除去すべく動作する。Next, the gyrator filters 9 and 10 further limit the frequency of their output signals and operate to completely remove adjacent frequency signal components.
【００２３】この従来の受信機では、ミキサ回路５，
６は周波数特性を有していないため、希望の周波数信号
成分と隣接周波数信号成分の上記フィルタ部に対する入
力信号レベルはこのミキサ部の出力レベルに反映する。In this conventional receiver, the mixer circuit 5,
6 does not have frequency characteristics, the input signal levels of the desired frequency signal component and adjacent frequency signal components to the filter section are reflected in the output level of this mixer section.
【００２４】つまり、この種の従来の受信機では、希望
の周波数信号成分を得る際、隣接周波数信号成分を除去
する処理に関して、ミキサ部の後段のフィルタ部の負担
が極めて大きい。In other words, in this type of conventional receiver, when obtaining a desired frequency signal component, the burden on the filter section subsequent to the mixer section is extremely heavy regarding the process of removing adjacent frequency signal components.
【００２５】そのための対策として、従来は、フィルタ
部をプレフィルタとジャイレータフィルタとの２段構成
としているが、係る構成の受信機においても、希望の周
波数信号成分に対して隣接周波数信号成分が過大なＦＳ
Ｋ信号が受信された場合、ミキサ回路及びフィルタ部に
おける出力の歪を除去しきれないことがある。As a countermeasure for this, conventionally, the filter section has a two-stage configuration consisting of a pre-filter and a gyrator filter, but even in a receiver with such a configuration, the adjacent frequency signal component is excessively large relative to the desired frequency signal component. FS
When the K signal is received, distortion in the output of the mixer circuit and filter section may not be completely removed.
【００２６】この場合、ミキサ回路及びフィルタ部の出
力歪によって混変調が発生し、これがベースバンド信号
において歪成分として現れて、復調信号の精度を低下さ
せる原因となっていた。In this case, cross-modulation occurs due to output distortion of the mixer circuit and filter section, and this appears as a distortion component in the baseband signal, causing a decrease in the accuracy of the demodulated signal.
【００２７】[0027]
【発明が解決しようとする課題】このように上記従来の
ダイレクトコンバージョン受信機では、隣接周波数信号
成分を減衰させる機能をフィルタ部のみが担っていたた
め、隣接周波数信号の過入力があった場合の混変調を除
去しきれず、復調精度が著しく低下するという問題点が
あった。[Problems to be Solved by the Invention] As described above, in the above-mentioned conventional direct conversion receiver, only the filter section has the function of attenuating adjacent frequency signal components. There was a problem in that the modulation could not be completely removed and the demodulation accuracy decreased significantly.
【００２８】本発明はこの問題点を除去し、隣接周波数
信号成分を減衰させるためのフィルタ機能を増強し、隣
接周波数信号の過入力があった場合の混変調に対しても
安定に動作し、常に、高精度の復調信号を得ることので
きるＦＳＫ信号受信機を提供することを目的とする。The present invention eliminates this problem, strengthens the filter function for attenuating adjacent frequency signal components, and operates stably even against cross modulation when there is excessive input of adjacent frequency signals. It is an object of the present invention to provide an FSK signal receiver that can always obtain highly accurate demodulated signals.
【００２９】［発明の構成］[Configuration of the invention]
【００３０】[0030]
【課題を解決するための手段】本発明は、１つの受信Ｆ
ＳＫ信号が分岐して与えられる一対の混合回路と、この
混合回路に前記ＦＳＫ信号の搬送周波数にほぼ等しい周
波数の局部発振信号を与える局部発振回路と、前記一対
の混合回路の各出力信号のＦＳＫ復調信号波がそれぞれ
通過する一対の低域ろ波器と、前記一対の混合回路の各
入力信号またはこの一対の混合回路に与える局部発振信
号のいずれかにほぼπ／２相当の位相差を与える移相回
路と、前記一対の低域ろ波器の出力信号を比較する比較
回路とを備えたＦＳＫ信号受信機において、前記一対の
混合回路内に、所望とするＦＳＫ復調信号波以外の周波
数成分を減衰させるろ波手段を具備した構成を有する。[Means for Solving the Problems] The present invention provides one receiving F.
a pair of mixing circuits to which the SK signal is branched and provided; a local oscillation circuit providing the mixing circuit with a local oscillation signal having a frequency approximately equal to the carrier frequency of the FSK signal; and an FSK signal for each output signal of the pair of mixing circuits. A pair of low-pass filters through which the demodulated signal waves pass, respectively, and a phase difference equivalent to approximately π/2 is given to either the input signals of the pair of mixing circuits or the local oscillation signals applied to the pair of mixing circuits. In the FSK signal receiver including a phase shift circuit and a comparison circuit that compares the output signals of the pair of low-pass filters, a frequency component other than the desired FSK demodulated signal wave is contained in the pair of mixing circuits. It has a configuration equipped with a filtering means for attenuating the.
【００３１】[0031]
【作用】本発明のＦＳＫ信号受信機は、１つの受信ＦＳ
Ｋ信号が分岐して与えられる一対のミキサ回路にも希望
の周波数信号成分以外の不要な信号成分を減衰させるフ
ィルタ特性を付加したものである。[Operation] The FSK signal receiver of the present invention has one reception FS.
A pair of mixer circuits to which the K signal is branched and provided are also provided with filter characteristics for attenuating unnecessary signal components other than the desired frequency signal components.
【００３２】この本発明の受信機では、まず、ミキサ回
路内で上記特性を有するフィルタ部により受信ＦＳＫ信
号中の不要な周波数信号成分を減衰させた後、更にその
後段にある本来のフィルタ部により希望周波数信号成分
以外の周波数制限を行う。In the receiver of the present invention, first, an unnecessary frequency signal component in the received FSK signal is attenuated by a filter section having the above-mentioned characteristics in the mixer circuit, and then an original filter section at the subsequent stage attenuates the unnecessary frequency signal component. Limit frequencies other than desired frequency signal components.
【００３３】このようなフィルタ機能の増強によって、
本発明では、隣接周波数信号の過入力があった場合にも
混変調を来さずに済み、常に、高精度の復調信号を得る
ことができる。[0033] By enhancing the filter function as described above,
According to the present invention, even if there is excessive input of adjacent frequency signals, cross modulation does not occur, and a highly accurate demodulated signal can always be obtained.
【００３４】また、本発明では、上記フィルタ機能の増
強により本来のフィルタ部における不要信号成分減衰の
ための処理の負担を軽減でき、これに伴って当該フィル
タ部からプレフィルタを削減する等、回路構成の簡素化
にも寄与できる。Furthermore, in the present invention, by enhancing the filter function described above, it is possible to reduce the burden of processing for attenuating unnecessary signal components in the original filter section. It can also contribute to simplifying the configuration.
【００３５】[0035]
【実施例】以下、本発明の実施例を添付図面に基づいて
詳細に説明する。DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
【００３６】図１は本発明に係るＦＳＫ信号受信機の一
実施例を示すブロック図である。FIG. 1 is a block diagram showing an embodiment of an FSK signal receiver according to the present invention.
【００３７】この本発明のＦＳＫ信号受信機において、
１つの受信ＦＳＫ信号が分岐して与えられるミキサ回路
５０， ６０は図３に示す従来装置のミキサ回路５，
６とは異なった構成を有し、それ以外の構成は図３に示
した従来装置と同様である。[0037] In the FSK signal receiver of the present invention,
The mixer circuits 50 and 60 to which one received FSK signal is branched and given are the mixer circuits 5 and 60 of the conventional device shown in FIG.
6, and the other configurations are the same as the conventional device shown in FIG.
【００３８】この本発明装置に新たに採用されるミキサ
回路５０， ６０の回路構成は、図２に示される。The circuit configuration of the mixer circuits 50 and 60 newly employed in the device of the present invention is shown in FIG.
【００３９】図２において、ミキサ回路５０， ６０は
シングルバランスミキサ７１とローパスフィルタ７２と
により構成される。In FIG. 2, mixer circuits 50 and 60 are composed of a single balanced mixer 71 and a low-pass filter 72.
【００４０】このうち、シングルバランスミキサ７１は
差動動作するトランジスタＴＲ１ とＴＲ２ 、及びそ
のエミッタ対に接続されるトランジスタＴＲ３ を具備
し、ローパスフィルタ７２は抵抗Ｒ１，Ｒ２ とコンデ
ンサＣによって成る。Of these, the single balanced mixer 71 includes differentially operated transistors TR1 and TR2, and a transistor TR3 connected to the emitter pair thereof, and the low pass filter 72 includes resistors R1, R2 and a capacitor C.
【００４１】シングルバランスミキサ７１には、３つの
入力端子と２つの出力端子が設けられる。Single balanced mixer 71 is provided with three input terminals and two output terminals.
【００４２】７１１， ７１２はローカル信号（局部発
振信号）入力端子であり、図１の回路図では局部発振回
路３または移相回路４の出力に接続される。Reference numerals 711 and 712 are local signal (local oscillation signal) input terminals, which are connected to the output of the local oscillation circuit 3 or the phase shift circuit 4 in the circuit diagram of FIG.
【００４３】７１３はＲＦ入力端子であり、図１の回路
図では高周波増幅器２の出力に接続される。Reference numeral 713 is an RF input terminal, which is connected to the output of the high frequency amplifier 2 in the circuit diagram of FIG.
【００４４】７２１， ７２２は差動出力端子であり、
図１の回路図ではジャイレータフィルタ９， １０の入
力に接続される。721 and 722 are differential output terminals,
In the circuit diagram of FIG. 1, it is connected to the inputs of gyrator filters 9 and 10.
【００４５】次に、その動作を説明する。Next, its operation will be explained.
【００４６】図１において、アンテナ１により受信され
たＦＳＫ信号は高周波増幅器２で増幅された後、分岐さ
れてミキサ回路５０， ６０に入力する。In FIG. 1, an FSK signal received by an antenna 1 is amplified by a high frequency amplifier 2, and then branched and input to mixer circuits 50 and 60.
【００４７】これを図２に示すミキサ回路内の動作に当
てはめてみると、上記受信ＦＳＫ信号はシングルバラン
スミキサ７１のＲＦ入力端子７１３に対して入力する。Applying this to the operation within the mixer circuit shown in FIG. 2, the received FSK signal is input to the RF input terminal 713 of the single balanced mixer 71.
【００４８】この時、ローカル信号入力端子７１１，
７１２のうちの一方に対しては局部発振回路３から発生
した局部発振信号が直接、また、他の一方に対しては移
相回路４を通じてπ／２だけ移相された局部発振信号が
入力する。At this time, the local signal input terminal 711,
The local oscillation signal generated from the local oscillation circuit 3 is directly input to one of the 712, and the local oscillation signal whose phase has been shifted by π/2 is input to the other one through the phase shift circuit 4. .
【００４９】これら各入力信号はミキサ回路内で混合さ
れ、トランジスタＴＲ１，ＴＲ２ のコレクタより差動
出力される。These input signals are mixed in the mixer circuit and output differentially from the collectors of transistors TR1 and TR2.
【００５０】具体的には、ＲＦ入力端子７１３から入力
した受信ＦＳＫ信号はトランジスタＴＲ３ で増幅され
た後、トランジスタＴＲ１ により局部発振信号の一方
と混合され、そのコレクタを通じて差動出力端子７２２
に出力される。Specifically, the received FSK signal inputted from the RF input terminal 713 is amplified by the transistor TR3, and then mixed with one of the local oscillation signals by the transistor TR1, and then sent to the differential output terminal 722 through its collector.
is output to.
【００５１】これと同時に、トランジスタＴＲ３ で増
幅された受信ＦＳＫ信号はトランジスタＴＲ２ により
局部発振信号の他の一方と混合され、そのコレクタを通
じて差動出力端子７２１に出力される。At the same time, the received FSK signal amplified by the transistor TR3 is mixed with the other local oscillation signal by the transistor TR2, and is output to the differential output terminal 721 through its collector.
【００５２】この差動出力端子７２１， ７２２に対す
る差動出力には、通常、隣接周波数信号を含んだ様々な
不要信号成分が含まれている。The differential output from the differential output terminals 721 and 722 usually contains various unnecessary signal components including adjacent frequency signals.
【００５３】本発明のＦＳＫ受信機では、これらの不要
周波数信号成分をローパスフィルタ７２により減衰させ
ることができる。In the FSK receiver of the present invention, these unnecessary frequency signal components can be attenuated by the low-pass filter 72.
【００５４】図２において、トランジスタＴＲ１，ＴＲ
２ のコレクタに接続される抵抗Ｒ１，Ｒ２ （Ｒ１
＝Ｒ２ ）は対応するトランジスタＴＲ１，ＴＲ２ の
コレクタ電位を決定すべく用いられるものであるが、本
発明では、これら抵抗Ｒ１，Ｒ２ がその間に接続され
るコンデンサＣとともに交流的にローパスフィルタ７２
を構成している。In FIG. 2, transistors TR1, TR
Resistors R1 and R2 (R1
=R2) is used to determine the collector potential of the corresponding transistors TR1, TR2, but in the present invention, these resistors R1, R2, together with the capacitor C connected between them, are used to connect the low-pass filter 72 in an AC manner.
It consists of
【００５５】上述の如くトランジスタＴＲ１，ＴＲ２
のコレクタを通じて差動電圧が入力され条件の下で、こ
のローパスフィルタ７２の特性を解析すると、そのカッ
トオフ周波数ｆｃ は、
ｆｃ ＝１／２π×（２Ｃ）×Ｒ１（２）となる。As described above, transistors TR1 and TR2
When the characteristics of the low-pass filter 72 are analyzed under the condition that a differential voltage is input through the collector of the low-pass filter 72, the cutoff frequency fc becomes fc = 1/2π×(2C)×R1(2).
【００５６】つまり、本発明では図２に示す如くの回路
構成によりミキサ回路５０， ６０にカットオフ周波数
ｆｃ のローパスフィルタ特性を持たせることができる
。That is, in the present invention, the mixer circuits 50 and 60 can be provided with a low-pass filter characteristic of the cutoff frequency fc by the circuit configuration shown in FIG.
【００５７】このローパスフィルタ特性によって、ミキ
サ回路５０， ６０内では、受信ＦＳＫ信号の隣接周波
数信号成分が減衰され、希望の周波数信号成分よりもか
なり小さく抑えられる。Due to this low-pass filter characteristic, adjacent frequency signal components of the received FSK signal are attenuated in the mixer circuits 50 and 60, and are suppressed to be much smaller than the desired frequency signal component.
【００５８】その後、このミキサ回路５０， ６０の出
力はジャイレータフィルタ９， １０を通過するが、そ
の際も、そのフィルタ特性に従って希望周波数信号成分
以外の不要信号成分が更に減衰される。Thereafter, the outputs of the mixer circuits 50, 60 pass through the gyrator filters 9, 10, at which time unnecessary signal components other than the desired frequency signal components are further attenuated according to the filter characteristics.
【００５９】このジャイレータフィルタ９， １０の出
力は低周波増幅器１１， １２により増幅され、更に振
幅制限回路１３， １４により一定幅の振幅制限を受け
つつ比較回路１５に入力される。The outputs of the gyrator filters 9 and 10 are amplified by low frequency amplifiers 11 and 12, and are further input to a comparator circuit 15 while being subjected to a constant amplitude limit by amplitude limiting circuits 13 and 14.
【００６０】比較回路１５では、振幅制限回路１３，
１４からの入力信号の位相の進み具合（図５及び６参照
）から受信ＦＳＫ信号の周波数偏移の＋δと−δを識別
し、その結果に基づいて受信ＦＳＫ信号を復調する。In the comparison circuit 15, the amplitude limiting circuit 13,
The frequency shift +δ and -δ of the received FSK signal are identified from the phase advance of the input signal from 14 (see FIGS. 5 and 6), and the received FSK signal is demodulated based on the result.
【００６１】このように本発明では、１つの受信ＦＳＫ
信号が分岐して与えられるミキサ回路にもローパスフィ
ルタ特性を付加することで、希望周波数信号成分以外の
不要周波数信号成分に対するフィルタ機能を高めるよう
にしている。[0061] In this way, in the present invention, one receiving FSK
By adding a low-pass filter characteristic to the mixer circuit to which the signal is branched and provided, the filtering function for unnecessary frequency signal components other than the desired frequency signal component is enhanced.
【００６２】この回路構成によれば、受信ＦＳＫ信号に
関する隣接周波数信号の過入力があった場合でも混変調
を来さずに済み、精度の高い復調信号が得られる。According to this circuit configuration, even if there is excessive input of an adjacent frequency signal related to the received FSK signal, cross-modulation does not occur, and a highly accurate demodulated signal can be obtained.
【００６３】また、ミキサ回路にローパスフィルタ特性
を持たせたことの別の効果として、その後段にあるフィ
ルタ部における不要周波数信号成分の減衰処理に関する
負担を軽減することができる。Another effect of providing the mixer circuit with low-pass filter characteristics is that the burden associated with attenuation processing of unnecessary frequency signal components in the subsequent filter section can be reduced.
【００６４】このため、不要周波数信号成分を充分に満
足のいくレベルまで減衰させるために、従来、プレフィ
ルタ７， ８とジャイレータフィルタ９，１０との２段
構成を余儀なくされていたフィルタ部（図３参照）を、
ジャイレータフィルタ９， １０だけで構成でき（図１
参照）、回路構成の簡略化にも寄与できる。Therefore, in order to attenuate unnecessary frequency signal components to a sufficiently satisfactory level, the filter section (Fig. 3)),
It can be configured with only gyrator filters 9 and 10 (Fig. 1
), it can also contribute to the simplification of the circuit configuration.
【００６５】[0065]
【発明の効果】以上説明したように本発明のＦＳＫ信号
受信機によれば、１つの受信ＦＳＫ信号が分岐して与え
られる一対のミキサ回路にもフィルタ特性を付加し、不
要信号成分に対するフィルタ機能を増強するようにした
ため、隣接周波数信号成分の過入力時における混変調に
対しても安定に動作せしめて高精度の復調信号を得るこ
とができるとともに、ミキサ回路の後段にある本来のフ
ィルタ部の負担を軽減して回路の簡素化にも寄与できる
という優れた利点を有する。As explained above, according to the FSK signal receiver of the present invention, a filter characteristic is added to a pair of mixer circuits to which one received FSK signal is branched and provided, thereby improving the filter function for unnecessary signal components. As a result, it is possible to operate stably even in the case of cross-modulation caused by excessive input of adjacent frequency signal components, and to obtain a highly accurate demodulated signal. This has the excellent advantage of reducing the burden and contributing to the simplification of the circuit.
【図１】本発明に係るＦＳＫ信号受信機の一実施例を示
すブロック回路図。FIG. 1 is a block circuit diagram showing an embodiment of an FSK signal receiver according to the present invention.
【図２】本発明に係るＦＳＫ信号受信機のミキサ回路の
詳細構成を示す回路図。FIG. 2 is a circuit diagram showing a detailed configuration of a mixer circuit of an FSK signal receiver according to the present invention.
【図３】この種の従来のＦＳＫ信号受信機の一般的構成
を示すブロック回路図。FIG. 3 is a block circuit diagram showing the general configuration of this type of conventional FSK signal receiver.
【図４】ＦＳＫ信号受信機で処理する２値ＦＳＫ信号の
スペクトラムを示す図。FIG. 4 is a diagram showing a spectrum of a binary FSK signal processed by an FSK signal receiver.
【図５】受信ＦＳＫ信号の周波数偏移δが正の時のＩ信
号とＱ信号との位相関係を示す図。FIG. 5 is a diagram showing the phase relationship between an I signal and a Q signal when the frequency shift δ of the received FSK signal is positive.
【図６】受信ＦＳＫ信号の周波数偏移δが負の時のＩ信
号とＱ信号との位相関係を示す図。FIG. 6 is a diagram showing the phase relationship between an I signal and a Q signal when the frequency shift δ of the received FSK signal is negative.
１ アンテナ
２ 高周波増幅器
３ 局部発振回路
４ 移相回路
５０， ６０ ミキサ回路
９， １０ ジャイレータフィルタ
１１， １２ 低周波増幅器
１３， １４ 振幅制限回路
１５ 比較回路
７１ シングルバランスミキサ
７２ ローパスフィルタ
７１１， ７１２ ローカル信号入力端子７１３
ＲＦ入力端子
７２１， ７２２ 差動出力端子1 Antenna 2 High frequency amplifier 3 Local oscillation circuit 4 Phase shift circuit 50, 60 Mixer circuit 9, 10 Gyrator filter 11, 12 Low frequency amplifier 13, 14 Amplitude limiting circuit 15 Comparison circuit 71 Single balance mixer 72 Low pass filter 711, 712 Local signal Input terminal 713
RF input terminals 721, 722 differential output terminals
Claims (3)
られる一対の混合回路と、この混合回路に前記ＦＳＫ信
号の搬送周波数にほぼ等しい周波数の局部発振信号を与
える局部発振回路と、前記一対の混合回路の各出力信号
のＦＳＫ復調信号波がそれぞれ通過する一対の低域ろ波
器と、前記一対の混合回路の各入力信号またはこの一対
の混合回路に与える局部発振信号のいずれかにほぼπ／
２相当の位相差を与える移相回路と、前記一対の低域ろ
波器の出力信号を比較する比較回路とを備えたＦＳＫ信
号受信機において、前記一対の混合回路内に、所望とす
るＦＳＫ復調信号波以外の周波数成分を減衰させるろ波
手段を付加したことを特徴とするＦＳＫ信号受信機。1. A pair of mixing circuits to which one received FSK signal is branched and provided; a local oscillation circuit providing the mixing circuit with a local oscillation signal having a frequency approximately equal to the carrier frequency of the FSK signal; A pair of low-pass filters through which the FSK demodulated signal waves of the output signals of the mixing circuits pass, and approximately π for either the input signals of the pair of mixing circuits or the local oscillation signals applied to the pair of mixing circuits. /
In the FSK signal receiver including a phase shift circuit that provides a phase difference equivalent to 2, and a comparison circuit that compares the output signals of the pair of low-pass filters, a desired FSK An FSK signal receiver characterized in that a filtering means is added to attenuate frequency components other than demodulated signal waves.
られることを特徴とする請求項１記載のＦＳＫ信号受信
機。2. The FSK signal receiver according to claim 1, wherein the filtering means includes a low-pass filter.
出力を取り出すべき２つのトランジスタのコレクタに個
別に接続される各負荷抵抗間にコンデンサを接続した構
成を有することを特徴とする請求項２記載のＦＳＫ信号
受信機。［発明の目的］3. The filtering means has a configuration in which a capacitor is connected between each load resistor that is individually connected to the collector of two transistors from which each output of the pair of mixing circuits is taken out. Item 2. FSK signal receiver according to item 2. [Purpose of the invention]
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2705691A JPH04266243A (en) | 1991-02-21 | 1991-02-21 | Fsk signal receiver |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2705691A JPH04266243A (en) | 1991-02-21 | 1991-02-21 | Fsk signal receiver |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04266243A true JPH04266243A (en) | 1992-09-22 |
Family
ID=12210415
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2705691A Pending JPH04266243A (en) | 1991-02-21 | 1991-02-21 | Fsk signal receiver |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04266243A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7187230B2 (en) * | 2005-03-18 | 2007-03-06 | Nokia Corporation | Transferred-impedance filtering in RF receivers |
-
1991
- 1991-02-21 JP JP2705691A patent/JPH04266243A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7187230B2 (en) * | 2005-03-18 | 2007-03-06 | Nokia Corporation | Transferred-impedance filtering in RF receivers |
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