JPS58133005A - Fm demodulator - Google Patents
Fm demodulatorInfo
- Publication number
- JPS58133005A JPS58133005A JP1516882A JP1516882A JPS58133005A JP S58133005 A JPS58133005 A JP S58133005A JP 1516882 A JP1516882 A JP 1516882A JP 1516882 A JP1516882 A JP 1516882A JP S58133005 A JPS58133005 A JP S58133005A
- Authority
- JP
- Japan
- Prior art keywords
- output
- pass filter
- band
- multiplier
- filters
- 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.)
- Pending
Links
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
- H03D3/00—Demodulation of angle-, frequency- or phase- modulated oscillations
- H03D3/007—Demodulation of angle-, frequency- or phase- modulated oscillations by converting the oscillations into two quadrature related signals
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Circuits Of Receivers In General (AREA)
Abstract
Description
【発明の詳細な説明】
不発−はFM復調IIk係り、41に直交検波器を用い
たFM復調器の改jlLK関する。FM復調器として、
これまで直交検波器を用いた方式が、例えば参考文献唱
和藝年畳許会告第1m3号「周IIIL数弁別回路」あ
るいは英−特許jl 11110m 号「−dmlat
@rf@r F M Signals J (公告1r
rs都■月)のよ5に知られている。このようなFM復
調器を中心周波数を一定間隔だaす離して配置した周波
数分割チャンネルに適用した鳩舎、チャンネル選択度が
すなわち、ある希望するチャンネルを受信するとき、他
のチャンネルの影響をどれはと避けることができるかが
、不十分でありた。DETAILED DESCRIPTION OF THE INVENTION Misfiring relates to FM demodulation IIk, and 41 relates to modification of the FM demodulator using a quadrature detector. As an FM demodulator,
Up until now, methods using quadrature detectors have been used, for example, References Showa Gei Nen Tatami Kōkai Hikaku No. 1m3 ``Shu IIIL Number Discriminator Circuit'' or British Patent Jl No. 11110m ``-dmlat
@rf@r FM Signals J (Notice 1r
rs capital ■ month) is known to 5. When such an FM demodulator is applied to frequency-divided channels whose center frequencies are spaced a certain distance apart, the channel selectivity is that when receiving a certain desired channel, how much influence from other channels is received. However, it was insufficient to be able to avoid it.
本発明の目的は、この欠点を除き、十分な為ンネル選択
度を有するFM復調器を提供することにある。The object of the present invention is to eliminate this drawback and provide an FM demodulator with sufficient channel selectivity.
本発明によれば、位相が900だけ異なる$111と菖
2の局部発振出力な有する局部発振器と、受信FM変調
波とそれぞれ前記第1および第2の局部発振出力を入力
とする第1および第2の周波数変換器と、#第1および
1lE2の周波数変換器のそれぞれの出力を入力とする
第1および第2の帯域通過フィルタと、鋏第1の帯域通
過フィルタの出力の一部を人力とする第1の微分回路と
、前記第2の帯域通過フィルタの出力の一部を人力とす
る第2の微分回路と、前記JI11の帯域通過フィルタ
の出力と前記第2の微分回路の出力を入力とする第1の
乗算器と、前記第2の帯域通過フィルタの出力と前記第
1の微分回路の出力とを入力とする第2の乗算器とを設
け、前記第1の乗算器の出力と前記第2の乗算器の出力
とを減算回路に入力して得られる出力を復調出力とする
ことによって、この目的を達成できる。According to the present invention, there is provided a local oscillator having local oscillation outputs of $111 and iris 2 whose phases differ by 900, and first and second local oscillators whose inputs are the received FM modulated wave and the first and second local oscillation outputs, respectively. #2 frequency converter, first and second band pass filters that receive the outputs of the first and #11E2 frequency converters as inputs, and a part of the output of the scissors first band pass filter. a first differentiating circuit that inputs the output of the band-pass filter of the JI11 and the output of the second differentiating circuit. and a second multiplier whose inputs are the output of the second bandpass filter and the output of the first differentiation circuit, and the output of the first multiplier is This objective can be achieved by inputting the output of the second multiplier to a subtraction circuit and using the resulting output as a demodulated output.
以下、図面と式を用いて詳しい説明を行う。A detailed explanation will be given below using drawings and formulas.
第1図は本発明の実施例を示すプロ1フ図である。入力
趨子lOに入力されるFM信号は一般的に次のように表
わされる。FIG. 1 is a profile diagram showing an embodiment of the present invention. The FM signal input to the input trend lO is generally expressed as follows.
Rtt+ = A cos (鴨t+a(t))・・・
・・・・・・・・・・・・(1)こ五で、ムは!@、m
、は中心周波数!あり、さである。こ工で、βは蛮勇指
数#l(4は変輿入方信号である。Rtt+ = A cos (duck t+a(t))...
・・・・・・・・・・・・(1) Kogo de Muha! @, m
, is the center frequency! There is and there is. In this work, β is the brutality index #l (4 is the hen-koshi entry signal.
局部発振優美の出力を
1(t)=laII&(鴫0・・・・・・・・・・・・
・・曲・・・・旧・・体)とすれば JIIIの周波数
変換器4の出方は、−一(t)=ム凰5in((へ−鴫
−・)tl5(t))十Ax 51j((−、+# )
t + s(g))”・・・・(4)となる。111
2の周波数変換5122の出力は、Rjt) =B*
”((曽* −”e ) t + a(t))+ml鍋
〔(−6十−)盛士a(tリー・・・(2)となる。&
(t)および&(t)の右辺の嬉2項は、高次成分であ
るが、111項の基本成分と周波数が大きく離れるため
kその除去は容易である。The output of the local oscillation grace is 1(t) = la II & (Shizu 0...)
...song... old... body), the output of JIII's frequency converter 4 is -1 (t) = mu 5 in ((he - 鴫 -) tl5 (t)) 10 Ax 51j ((-, +#)
t + s(g))”...(4).111
The output of the frequency conversion 5122 of 2 is Rjt) = B*
"((So * -"e) t + a(t)) + ml pot [(-60-) Seishi a(t Lee...(2).&
Although the second term on the right side of (t) and &(t) is a high-order component, it is easy to remove it because its frequency is significantly different from the fundamental component of the 111th term.
周波数分割チャンネルにおいて、S*のチャンネルが同
時に使用されている場合において、希望チャンネルだけ
分離することは、上記の場合と比べてmsである。受信
六方が複数の場合には式(4)(51かられかるようK
、周波数変換器の出力のスペクトルはm2tjAに示す
よ5になる。In the frequency division channel, when S* channels are used simultaneously, it takes ms to separate only the desired channel compared to the above case. When there are multiple receiving hexagons, K is calculated from formula (4) (51).
, the spectrum of the output of the frequency converter is 5 as shown in m2tjA.
このよ5KII数のチャンネルから、希望チャンネルの
みを選択するために、従来の直交検波臘周波数弁別器は
低域通過フィルタを用いていた。しかし一般に、低域通
過フィルタの通過特性な急峻にすることは困−で、隣接
チ、ヤンネルの干渉を極めて低くすることができなかっ
た。良く知られているようにセラミック振動子や水晶振
動子を用いた帯域通過J1フィルタは極めて急峻な通過
特性を示すので隣接チャンネルの干渉を低く、シたがり
てチャンネル選択度を上げることができる。In order to select only a desired channel from these 5KII channels, a conventional quadrature detection frequency discriminator uses a low-pass filter. However, it is generally difficult to make the pass characteristics of a low-pass filter steep, and it has been impossible to extremely reduce interference between adjacent channels and channels. As is well known, a band-pass J1 filter using a ceramic resonator or a crystal resonator exhibits an extremely steep pass characteristic, thereby reducing interference between adjacent channels and thereby increasing channel selectivity.
今、簡単のために、希望波の中心周波数と局部発振器の
周波数差を輪とし、したがって帯域通過フィルタの中心
周波数なこの値に一部させるものとする。またフィルタ
の特性は壇想的なものとしよう。帯域通過フィルタ51
、52の出力はそれぞれ次のようになる。Now, for the sake of simplicity, it is assumed that the frequency difference between the center frequency of the desired wave and the local oscillator is a ring, and therefore the center frequency of the bandpass filter is a part of this value. Also, let's assume that the characteristics of the filter are arbitrary. Bandpass filter 51
, 52 are as follows.
Rs(t)”ん$」〔輌t+5(t))・・・・・・・
・・・・・・・・・・・俤)&(tl = AsCXl
5 (Q g + a lt) ) −・−・−−−−
・−・・−−−−(7)黴分闘1161,62の出力は
、
m’&)=血(s+/ f(t))ai(*** +
#(t))−1)&(1)=+、^l〔−1千 β 豐
(をン )sin(mt+s(處) 〕 ・・・惨)と
なる。したがって、乗算1路71の出力は、c、<t>
=−鳩〔町+β* (t) ) m”(St+1(1)
)−・・・・・昧・となり、乗算回路nの出力は、
9g)=j4AJツ+βw(t))硫ωt+5(t))
・・・・・・・・・・・・・・・軸となる。Rs(t)”$” [t+5(t))・・・・・・・・・
・・・・・・・・・・・・ 俤)&(tl = AsCXl
5 (Q g + alt) ) −・−・−−−−
・−・・−−−−(7) The output of mold fighting 1161, 62 is m'&) = blood (s + / f (t)) ai (*** +
#(t))-1)&(1)=+, ^l[-1,000 β 豐(woon)sin(mt+s(處)]...misery). Therefore, the output of the multiplication path 71 is c,<t>
=-Pigeon [Town+β* (t)) m”(St+1(1)
)−・・・・・・The output of the multiplier circuit n is: 9g)=j4AJtsu+βw(t))Sulfurωt+5(t))
・・・・・・・・・・・・・・・It becomes the axis.
したがって、減算回路nI)aS力は、D(t)=(、
(t) −(1,(t)=A14(&=+β9 (t)
’l −−−−−・illとなる。−は定数であるか
らこれを除けば、送信信号V (#)を復調することが
できる。Therefore, the subtraction circuit nI)aS force is D(t)=(,
(t) −(1, (t)=A14(&=+β9 (t)
'l ------・ill. Since - is a constant, if this is removed, the transmitted signal V (#) can be demodulated.
以上lll!明したように本発明においては、通過特性
の急峻な帯域通過フィルタを使用できるので、チャンネ
ル選択度を極めて轟くできる効果がある。That’s all! As explained above, in the present invention, since a band pass filter with a steep pass characteristic can be used, the channel selectivity can be extremely improved.
第1図は本発明の実施例を示すプロ1フ図、嬉2図は周
波数分割チャンネルを受信した場合の周波数変換器出力
スペクシルの概略■であり、これらのbicIにおいて
、10は受信入力端子、21 、22は周波数変換器、
(9)は局部発振器、鉛は90°位相器、5152は帝
域通過フィルタ、61.62は微分回路、71 。
72は乗算−路、73は減算−路、74は復調出力端子
である。
!1図
多乙図Fig. 1 is a profile diagram showing an embodiment of the present invention, and Fig. 2 is a schematic diagram of the frequency converter output spectrum when receiving a frequency division channel. 21 and 22 are frequency converters;
(9) is a local oscillator, lead is a 90° phase shifter, 5152 is an imperial pass filter, 61.62 is a differential circuit, and 71. 72 is a multiplication path, 73 is a subtraction path, and 74 is a demodulation output terminal. ! Figure 1 Taotzu
Claims (1)
るtithm発aSと、受信FM変調波とそれぞれ前記
第1および1/s2のss発振出力を入力とする第1お
よび第2の周数数、変換器と、該第1および凧2の膚練
敏変換器のそれぞれの出力を入力とする菖1および11
112の帯域通過フィルタと、該第1の帯域通過フィル
タの出力の一部を入力とするMlの微分−路と、前記第
2の帯域通過フィルタの出力の一部を入力とするjll
E2の微分回路と、前記第III)帯域通過フィルタの
出力と前記第2の微分−路の出力とを入力とする菖10
乗算器と、前記@2の帯域通過フィルタの出力と前記第
1の微分回路の出力とを入力とする第2の乗算器とを有
し、前記Islの乗算器の出力と前記$112の乗算器
の出力とを減算1111に入力して得られる出力な復調
出力とすることを畳黴としたFMg調器。tithm oscillation aS having ml and second local oscillation outputs whose phases are different by zero, and first and second frequencies whose inputs are the received FM modulated wave and the first and 1/s2 ss oscillation outputs, respectively. iris 1 and 11, each having a number, a transducer, and the respective outputs of the first and kite 2 skin agility transducers as inputs;
112 band-pass filter, a differential path of Ml which receives a part of the output of the first band-pass filter as input, and a jll which takes part of the output of the second band-pass filter as input.
an irises 10 which receives as inputs the differentiating circuit of E2, the output of the band pass filter III), and the output of the second differentiating path;
a multiplier; and a second multiplier that receives as input the output of the @2 bandpass filter and the output of the first differentiation circuit, and multiplies the output of the Isl multiplier by the $112. The FMg modulator is designed to input the output of the modulator to the subtractor 1111 to obtain a demodulated output.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1516882A JPS58133005A (en) | 1982-02-02 | 1982-02-02 | Fm demodulator |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1516882A JPS58133005A (en) | 1982-02-02 | 1982-02-02 | Fm demodulator |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS58133005A true JPS58133005A (en) | 1983-08-08 |
Family
ID=11881267
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP1516882A Pending JPS58133005A (en) | 1982-02-02 | 1982-02-02 | Fm demodulator |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS58133005A (en) |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2645950A1 (en) * | 1975-10-14 | 1977-04-28 | Int Standard Electric Corp | RADIO RECEIVER FOR FREQUENCY MODULATED SIGNALS |
-
1982
- 1982-02-02 JP JP1516882A patent/JPS58133005A/en active Pending
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2645950A1 (en) * | 1975-10-14 | 1977-04-28 | Int Standard Electric Corp | RADIO RECEIVER FOR FREQUENCY MODULATED SIGNALS |
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