JPS59171203A - Product detecting circuit for quadrature fm demodulation circuit - Google Patents
Product detecting circuit for quadrature fm demodulation circuitInfo
- Publication number
- JPS59171203A JPS59171203A JP58044108A JP4410883A JPS59171203A JP S59171203 A JPS59171203 A JP S59171203A JP 58044108 A JP58044108 A JP 58044108A JP 4410883 A JP4410883 A JP 4410883A JP S59171203 A JPS59171203 A JP S59171203A
- Authority
- JP
- Japan
- Prior art keywords
- dropout
- signal
- circuit
- output
- quadrature
- 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
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
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Television Signal Processing For Recording (AREA)
Abstract
Description
【発明の詳細な説明】
〔発明の利用分野〕
本発明は、入力されるＦＭ信号のドロップアウト検出回
路に関するものであり、史に詳しくは、クオードラチャ
＠２調回路と組合せて構成される、この種ドロップアウ
ト検出回路に関するものである。[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a dropout detection circuit for an input FM signal. The present invention relates to this type of dropout detection circuit.
し従来技術〕
従来ＦＭ後詳１回路のドロップアウト検出には、ＰＬＬ
Ｋより、入力のｆ” Ｍ周波数に追従させ、そのＶＣＵ
（電圧制御発振器っの入力電圧をＦＭ後調信号電圧とし
、ドロップアウトの検出は、位相ロックが、はずれたこ
とを検出して行っていた。しかしながら、Ｐ Ｌ ｉ、
の回路で＆’ｉ Ｖ ＣＯ等が必要なため、コストが高
くなるといった次点があった。Conventional technology] Conventionally, PLL is used to detect dropout of one circuit after FM.
From K, follow the input f''M frequency, and the VCU
(The input voltage of the voltage controlled oscillator was the FM post-tone signal voltage, and dropout was detected by detecting that the phase lock was lost. However, P L i,
The runner-up was that the cost was high because the &'i V CO etc. were required in the circuit.
本発明の目的は、…Ｊ記従来の欠点である、市価なＰ
Ｌ ］、を廃１７、安価なりえ一ドラチャゆ調力式を採
用し、て且つドロップアウトを検出できるドロップアウ
ト検出回路を提供１′ることにあ杭
１、発明の概要〕
ドロップアウトは、Ｆ Ｍ周波数が瞬間的に低下する現
象であり、その低下速度及び低下周波数が、ｌｉ” ｈ
ｉ変調波の周波数及び振幅な、はく）かに糾えたもので
あることに着目し、復調出力にて、キャリア遮り用ロー
パスフィルタ′？：辿り抜に−ｊた信号の不要高域成分
が、ル・る程度し１土のレベルして梓Ｌ７、一時にドＬ
ンフ”アウトとして土芙出１−４）こととしまた−８
実施例
Ｊ以１、本発明□の一実施例を、図により説明−する。The purpose of the present invention is to...
1. To provide a dropout detection circuit that adopts an inexpensive power control system and is capable of detecting dropouts. 1. Overview of the invention This is a phenomenon in which the FM frequency drops instantaneously, and the rate of decline and frequency of the decline are
Focusing on the fact that the frequency and amplitude of the i-modulated wave are very sharp, a low-pass filter for carrier blocking is applied to the demodulated output. :The unnecessary high-frequency components of the signal that has been traced are at the level of 1, and the level of Azusa L7, and the low level at the same time.
1-4) 8. Example J to 1, an example of the present invention □ will be explained with reference to the drawings.
図（・コおいて、１はＰ Ｍ信−弓の入力端子でキ）す
、ＣＣＫ人力さｆｔたＦ Ｉ’ｖｌイＨ号はリミッタ２
で増幅さハ、矩形波となる。この出力信号は一９００移
相器５で中心周波数で９００シフトし、移相器６を、１
口１〕ない信号と共に、乗算器４で乗算される。この出
力は、移調信号の他に、ギヤリアの２倍の周波数のスペ
クトラムを含む。この２倍波はローパスフィルタ５で殆
んど取り除かれ出力さｆｌ、る。さらにこの出力は、Ｓ
／Ｎ比改善のため、抵抗６及びコンデンサ７で構成さｔ
しるローパスフィルタにより、必要周波数以上のスペク
トラムが、落とさ′ｉＬる。この際、ドロップアウトに
より、Ｆ Ｍ信号が欠落すると、その期間だけ、Ｆ Ｍ
の周波数が、極めて低下するため、ローパスフィルタ５
及びａ 抗、ｓ 、コンブンづ７によるローパスフィル
タな通り抜けて、ド［ｊノブアウトノイズとして観測さ
れる。しかしながらトランジスタ８０ベース、エミッタ
端ｆが抵抗６の両端に接続されているので、ドロツノア
ウトが発生し７て、１・゛Ｍ信号の周波数が極めで低下
１−ると、ドロップアウトノイズが抵抗６、・コンデン
サ７のローパスフィルタな通過−１６際、このノイズが
高い周波数成分を含むためトランジスタ８が導通し、抵
抗９を介してトランジスタ１１か酌通し、瞬間的にコン
デンサ１４の電荷を放電し、トランジスタ１１のコレク
タを位が上昇する。１５は、制御乱用が上昇すると遮断
するアナログスイッチであり、従ってドロップアウトが
あζ）と、アナログスイッチ１５かオーフンし、その直
前の電圧が、ホールドコンデンサ１６により保持される
ため、出力端子１７には、ドロップアウトノイズが、出
ない。入力のドロップアウト状態が解除されても、ロー
ムスフ１ルタには、その影響か残一つでいるか、アナロ
グスイッチ１５は、コンデンサ１４と抵抗１りＫよる時
足叡及び、アナログスイッチ１５のスレッシュホールド
′ｒｔ！５圧で決定さｔｌ、る期間は、オーフン￥続け
るため、ドロップアウトノイズは、殆んど検知さｆ［な
い。In the figure, 1 is the PM signal input terminal of the bow.
Amplified by C, it becomes a square wave. This output signal is shifted by 900 at the center frequency by a 1900 phase shifter 5, and then shifted by 1900 at the center frequency.
[1] is multiplied by the multiplier 4 together with the non-signal. This output includes, in addition to the transposed signal, a spectrum at twice the frequency of the gear carrier. This second harmonic is almost removed by a low-pass filter 5 and output. Furthermore, this output is S
In order to improve the /N ratio, it is composed of a resistor 6 and a capacitor 7.
A low-pass filter that filters out spectra with frequencies above the required frequency is dropped. At this time, if the FM signal is lost due to dropout, the FM signal is lost for that period only.
Since the frequency of
and a resistance, s pass through a low-pass filter by the combination and are observed as knob-out noise. However, since the base and emitter terminals f of the transistor 80 are connected to both ends of the resistor 6, dropout noise occurs and the frequency of the 1.mm signal drops significantly.・When passing through the capacitor 7 as a low-pass filter, this noise contains high frequency components, so the transistor 8 becomes conductive, passing through the transistor 11 via the resistor 9, momentarily discharging the charge in the capacitor 14, and causing the transistor to The rank of 11 collectors increases. Reference numeral 15 denotes an analog switch that shuts off when control abuse increases. Therefore, if there is a dropout (ζ), the analog switch 15 will open and the voltage just before that will be held by the hold capacitor 16, so that the output terminal 17 will be There is no dropout noise. Even if the input dropout condition is canceled, the ROHMs filter will still have only one influence, and the analog switch 15 will be affected by the capacitor 14 and the resistor 1 - K, and the analog switch 15's threshold. 'rt! The dropout noise is almost undetectable because the period determined by the 5 pressure continues in the open period.
尚抵抗１０はトランジスタ１１を完全にカットガフさせ
るためのものである。Note that the resistor 10 is provided to completely cut off the transistor 11.
」ン＋述べた様に、本発明によれば、高ｆ１１１１なＰ
Ｌ Ｊ、方式の←自回路を用いなくても、ドロップアウ
トに対処できるようになり、安価なＦ Ｍり自回路が得
ろ４７る。As stated above, according to the present invention, high f1111 P
LJ, method ← Dropouts can be dealt with without using the own circuit, and an inexpensive FM own circuit can be obtained47.
図は本発明の一実施例を示す１１路図である。 符号説明 １・・・入力端子 ２ ・・・ リ ミ ッ 七ス ３・・・移相器 ４・・・乗算器 ５・・ローパスフづルタ （Ｓ、９，１０．１３・・・抵抗 ７．１４・・コンデンサ ８．１１・・トランジスタ １５・・・スイッチ １６・・保持コンデンサ １７・・出力端子 The figure is an 11-way diagram showing one embodiment of the present invention. Code explanation 1...Input terminal 2... ri mi sevens 3... Phase shifter 4... Multiplier 5. Low pass filter (S, 9, 10.13...Resistance 7.14...Capacitor 8.11...Transistor 15...Switch 16...Holding capacitor 17...Output terminal
Claims (1)
ードラチャＦＭ復調回路と、該彷調回路からの乗算出力
を人力されキャリアの２倍波抑圧を行って出力する第１
のローパスフィルタと、該フィルタからの出力を入力さ
ｔＬＩ力定周定周波数以上波数をカノトオノして出力す
る第２の口〜バスフィルタと、この第２のローパスフィ
ルタ出力をホールドコンテンサヲイ箱えた出力’１１１
１・＼導くスイッチ回路と、前記Ｆ Ｍ人カイへ号にド
ロップアウトが発生したとさ、目１」記第１のローパス
フィルタを通り抜けて第２のローパスフィルタに入力″
ｆるドロップアウトノイズ信号を検出してＡｉＪ記スイ
クテ回路を開く手段とを有して成り、ドロップアウト発
生時には、その直前の電圧な前記ホールドコンテンザに
より保持して出力するようにしたことを特徴とするクオ
ードラチャＦＭＧ調回路用ドロップアウト検出回路。1) A quadrature FM demodulation circuit that receives the FNl signal and outputs it as a rear leg, and a first quadrature FM demodulation circuit that manually suppresses the second harmonic of the carrier and outputs the multiplication output from the quadrature circuit.
A low-pass filter, a second bass filter that receives the output from the filter, and outputs the wave number above a constant frequency, and a hold capacity box for the output of the second low-pass filter. Output '111
1. If a dropout occurs in the switch circuit that leads and the FM signal, the signal passes through the first low-pass filter and is input to the second low-pass filter.
and a means for detecting a dropout noise signal and opening the AiJ switching circuit, and when a dropout occurs, the voltage immediately before the dropout is held by the hold condenser and output. Dropout detection circuit for quadrature FMG tone circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58044108A JPS59171203A (en) | 1983-03-18 | 1983-03-18 | Product detecting circuit for quadrature fm demodulation circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58044108A JPS59171203A (en) | 1983-03-18 | 1983-03-18 | Product detecting circuit for quadrature fm demodulation circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59171203A true JPS59171203A (en) | 1984-09-27 |
| JPH0153802B2 JPH0153802B2 (en) | 1989-11-15 |
Family
ID=12682413
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58044108A Granted JPS59171203A (en) | 1983-03-18 | 1983-03-18 | Product detecting circuit for quadrature fm demodulation circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59171203A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008532858A (en) * | 2005-03-08 | 2008-08-21 | リーフグリーン リミテッド | Aerosol dispenser |
-
1983
- 1983-03-18 JP JP58044108A patent/JPS59171203A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008532858A (en) * | 2005-03-08 | 2008-08-21 | リーフグリーン リミテッド | Aerosol dispenser |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0153802B2 (en) | 1989-11-15 |
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