JPS58155508A - Magnetic video recorder - Google Patents
Magnetic video recorderInfo
- Publication number
- JPS58155508A JPS58155508A JP57036415A JP3641582A JPS58155508A JP S58155508 A JPS58155508 A JP S58155508A JP 57036415 A JP57036415 A JP 57036415A JP 3641582 A JP3641582 A JP 3641582A JP S58155508 A JPS58155508 A JP S58155508A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- apl
- recording
- luminance signal
- circuit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
- G11B20/02—Analogue recording or reproducing
- G11B20/06—Angle-modulation recording or reproducing
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Television Signal Processing For Recording (AREA)
Abstract
Description
【発明の詳細な説明】
U) 発明の利用分野
本発明に磁気録画再生装置に関係し、特に輝度信号の信
号対雑音比の改善に関するものである。DETAILED DESCRIPTION OF THE INVENTION U) Field of Application of the Invention The present invention relates to a magnetic recording/reproducing device, and particularly to improving the signal-to-noise ratio of a luminance signal.
偉)従来技術
第1図は従来の磁気録画再生装置における輝度信号の信
号処理系統図である。B) Prior Art FIG. 1 is a signal processing system diagram of a luminance signal in a conventional magnetic recording/reproducing apparatus.
記録時にはローパスフィルタ1で3MH!程度に帯域制
限された輝度信号はビデオエンファシス回路2でその高
周波成分が強調された後、図示しないクランプ回路によ
り輝度信号の同期信号を所定電位にクランプし所定の周
波数で発信するFM変調回路3に供給され、そこで低搬
送波FM信号に変換される。その後記録等化回路4で磁
気テープ・ヘッド系におけるFM信号の伝送効率を高め
るように適当な記録等化特性を与えた後、記録アンプ5
を介して磁気ヘッド6から磁気テープ7に記録される。3MH with low pass filter 1 during recording! After the high-frequency components of the brightness signal, which has been band-limited to a certain degree, are emphasized by a video emphasis circuit 2, the synchronization signal of the brightness signal is clamped to a predetermined potential by a clamp circuit (not shown) and sent to an FM modulation circuit 3, which transmits the signal at a predetermined frequency. where it is converted to a low carrier FM signal. After that, the recording equalization circuit 4 provides appropriate recording equalization characteristics to improve the transmission efficiency of the FM signal in the magnetic tape head system, and then the recording amplifier 5
The data is recorded from the magnetic head 6 onto the magnetic tape 7 via the magnetic head 6.
一方再生時には、磁気テープ・ヘッド系から再生アンプ
8を介して得た再生FM信号に再生等化回路9で、記録
側で行なった記録等化特性や磁気テープ・ヘッド系の下
側帯波を強調し、上側帯波を抑圧する伝送特性を補償さ
れる。さらにリミッタ回路10で磁気テープとヘッドの
接触状態の変動などで生じた振幅変動成分を取り除いた
後、FM復調回路11でFM復調し、工/ファシス回路
2と逆の特性を持つデイエ/7アシス回路12で元の輝
度信号を得ている。On the other hand, during playback, the playback equalization circuit 9 uses the playback FM signal obtained from the magnetic tape head system via the playback amplifier 8 to emphasize the recording equalization characteristics performed on the recording side and the lower sideband waves of the magnetic tape head system. However, the transmission characteristics that suppress the upper sideband are compensated. Furthermore, after removing amplitude fluctuation components caused by variations in the contact state between the magnetic tape and the head in the limiter circuit 10, FM demodulation is performed in the FM demodulation circuit 11. The circuit 12 obtains the original luminance signal.
第2図は従来の記録等化特性の1例で、FM信号の下側
帯波を強調し、上側帯波を抑圧する周波数特性を持つ。FIG. 2 shows an example of a conventional recording equalization characteristic, which has a frequency characteristic that emphasizes the lower sideband of an FM signal and suppresses the upper sideband.
FM信号の搬送波周波数は輝度信号のレベルと対応して
おり、例えばVB2−VTRの場合には第3図に示すよ
うに同期先端で&4MHz、白ピークで4.4MH1に
設定さレテいる。The carrier wave frequency of the FM signal corresponds to the level of the luminance signal, and in the case of a VB2-VTR, for example, it is set to &4 MHz at the synchronization tip and 4.4 MHz at the white peak, as shown in FIG.
従来の記録等化特性では、第2図に示すように常に輝度
信号の平均画傷レベル(Averagep 1ctur
e Level以下APL と略称する。)が灰色
レベルになるものと仮定し、灰色レベルの4、IMHg
をOdBとしている。しがしl11信号としては、第4
図(a)、 (b)に示すようにAFLかむしろ黒レベ
ルに近いもの(a)や、白レベルに近いもの(b)など
が数多く存在する。そこで第2図に示し次記録等化特性
でに、下側帯波の強調が充分でない場合や、強調しすぎ
るという問題も発生することになり、磁気テープ・ヘッ
ド系におけるFM信号の伝送効率を充分室めることがで
きない欠点がある。With conventional recording equalization characteristics, as shown in FIG.
e Level is abbreviated as APL. ) is assumed to be the gray level, and the gray level 4, IMHg
is taken as OdB. As the first l11 signal, the fourth
As shown in Figures (a) and (b), there are many types of AFL, such as AFL (a) which is close to the black level, and (b) which is close to the white level. Therefore, with the following recording equalization characteristics shown in Figure 2, the problem arises that the lower sideband is not emphasized enough or is overemphasized. There is a drawback that it cannot be roomed.
(3) 発明の目的
本発明はかかる欠点に対処できる記録等化特性を与えて
磁気テープ・ヘッド系におけるFM信号の伝送効率を高
め、再生輝度信号の信号対雑音比改善することを目的と
する。(3) Purpose of the Invention The object of the present invention is to improve the transmission efficiency of FM signals in a magnetic tape head system by providing recording equalization characteristics that can address these drawbacks, and to improve the signal-to-noise ratio of reproduced luminance signals. .
(4)発明の総括説明
上記目的を達成するために本発明では、輝度信号のAP
Lに応じて記録等化特性を下側帯波の強調が十分に行な
われ、上側帯波の抑圧が#1とんど′ ないように変え
るものである。(4) General explanation of the invention In order to achieve the above object, the present invention provides an AP for luminance signals.
According to L, the recording equalization characteristics are changed so that the lower sideband is sufficiently emphasized and the upper sideband is hardly suppressed.
(5) 実施例
以下、本発明を実施例を参照して詳細に説明する。第6
図が本発明の1実施例を示す輝度信号の信号処理系統図
である。同図中、第1図と同一構成部分には同一符号を
付し、その説明を省略する。(5) Examples Hereinafter, the present invention will be explained in detail with reference to examples. 6th
The figure is a signal processing system diagram of a luminance signal showing one embodiment of the present invention. In the figure, the same components as in FIG. 1 are denoted by the same reference numerals, and their explanations will be omitted.
記録時にはローパスフィルタlの出力である輝度信号は
ビデオエンファシス回路2と輝度信号のAPLt−求め
るためのローノくスフイルタ13とに分岐される。こう
して得たAPL信号に記録等化回路4′の記録等化特性
を変えるための制御信号となる。During recording, the luminance signal output from the low-pass filter 1 is branched to a video emphasis circuit 2 and a low-pass filter 13 for determining the APLt of the luminance signal. The APL signal thus obtained serves as a control signal for changing the recording equalization characteristics of the recording equalization circuit 4'.
第7図に本発明の構成要素である記録等化回路4′の1
実施例を示す。FIG. 7 shows part 1 of the recording equalization circuit 4' which is a component of the present invention.
An example is shown.
FM変調回路3の出力であるFM信号は端子15から直
流阻止用の容量C8ならびに電源Vccと抵抗R,、R
,とで構成したバイアス回路を経て抵抗R,tエミッタ
端に、抵抗Ratコレクタ端に接続してアンプを構成す
るトランジスタQ。The FM signal, which is the output of the FM modulation circuit 3, is transmitted from the terminal 15 to the DC blocking capacitor C8, the power supply Vcc, and the resistors R, , R.
, and a transistor Q, which is connected to the emitter end of the resistor R and t, and to the collector end of the resistor Rat, to form an amplifier.
で増幅される。容量C,は第2図に示したように下側帯
波を強調するための高周波成分のバイパス用である。そ
の後抵抗R,+コレクタ端に抵抗R6をエミッタ端に接
続したトランジスタQ、のベースに加わり、増幅される
。またトランジスタQ、のエミッタ端には直流阻止用の
容量Caを介してFM搬送波周波数fcで共振するイン
ダクタンスL1 と可変容量ダイオードD、とこの共
振回路のQを調整する抵抗R?が接続されている。した
がって、抵抗R1とエミッタ7オロワを構成するトラン
ジスタQsの出力端16には、第2図に示したような4
〜SMH2を平坦化し友記録等化を受けたFM信号が得
られる。可変容量ダイオードD1のカンード側の端子1
7KtX第7図に示すAPL信号が記録等化特性管変え
る制御信号として加わっている。このAPL信号のため
に可変容量ダイオードD1の容量が変化するため、第2
図に示した4〜5MHz近傍の平坦な部分がAPLt応
じて変化し、例えばAPLが白レベルに近いときには平
坦な部分が高周波数へ移動するすなわち、OdB基準が
高周波数へ移動するので常に最適な記録等化特性管与え
ることができる。is amplified. As shown in FIG. 2, the capacitor C is for bypassing high frequency components to emphasize the lower sideband. Thereafter, it is applied to the base of a transistor Q having a resistor R and a collector terminal connected to a resistor R6 and an emitter terminal, and is amplified. Further, at the emitter end of the transistor Q, there is an inductance L1 that resonates at the FM carrier frequency fc via a DC blocking capacitor Ca, a variable capacitance diode D, and a resistor R? that adjusts the Q of this resonant circuit. is connected. Therefore, the resistor R1 and the output terminal 16 of the transistor Qs constituting the emitter 7 lower are connected to the 4
~ SMH2 is flattened and an FM signal subjected to recording equalization is obtained. Cando side terminal 1 of variable capacitance diode D1
7KtX The APL signal shown in FIG. 7 is added as a control signal for changing the recording equalization characteristic tube. Since the capacitance of the variable capacitance diode D1 changes due to this APL signal, the second
The flat part near 4 to 5 MHz shown in the figure changes depending on APLt. For example, when APL is close to the white level, the flat part moves to a high frequency. In other words, the OdB standard moves to a high frequency, so it is always optimal. Recording equalization characteristics can be given to the tube.
このローパス4フイルタ13のしゃ新局波数f。The new station wave number f of this low-pass 4 filter 13.
ならびに次数nは、その遅延時間r、が1水平走査期間
になるように選ぶ。例えば無極ワグナ−型のローパスフ
ィルタの遅延時間rH次数nが小さい範囲で次式で求め
ることができる。and the order n are selected so that the delay time r is one horizontal scanning period. For example, the delay time rH of a non-polar Wagner type low-pass filter can be determined by the following equation as long as the order n is small.
そこで5次のワグナ−型ローパスフィルタを月いる場合
、(1)式よりjp ”i6にHEと求まる。Therefore, if a fifth-order Wagner type low-pass filter is used, HE can be determined from equation (1).
ここで、ローパスフィルタ13の遅延時間を1水平走査
期間にした理由は、APL信号とFM変調回路3の出力
であるFM信号との位相を合わせる几めである。さもな
いと輝度信号のAPLに応じて記録等化特性を変えるこ
とが適切にできない。Here, the reason why the delay time of the low-pass filter 13 is set to one horizontal scanning period is to match the phase of the APL signal and the FM signal which is the output of the FM modulation circuit 3. Otherwise, it is not possible to appropriately change the recording equalization characteristics according to the APL of the luminance signal.
輝度信号は一般に垂直方向の相関が強い。すなわち1水
平走査期間前の信号レベルと現在の信号レベルとの差は
ほとんどない。そこで上述し九ように1水平走査期間遅
れ7’jAPL信号で記録等化特性を変えるように制御
しても実用上問題ない。Luminance signals generally have strong correlation in the vertical direction. That is, there is almost no difference between the signal level one horizontal scanning period ago and the current signal level. Therefore, there is no practical problem even if the recording equalization characteristics are controlled to be changed by the 7'j APL signal delayed by one horizontal scanning period as described in 9 above.
以上述べたようにllf信号のAPLに応じて最適な記
録等化特性を与えるように常に制御が施されるので、磁
気テープ−ヘッド系の記録効率を常に最大に利用するこ
とができるため、再生輝度信号の信号対雑音比は従来よ
り数dB向上する。As mentioned above, since control is always performed to provide the optimum recording equalization characteristics according to the APL of the llf signal, the recording efficiency of the magnetic tape-head system can always be utilized to the maximum, so that playback is possible. The signal-to-noise ratio of the luminance signal is improved by several dB compared to the conventional method.
尚、第7図において、8〜12迄の再生系は別装置とし
ても良く、最少限本発明は、1〜3゜4′、5〜6およ
び13の録画系のみで完成する。In FIG. 7, the reproduction systems 8 to 12 may be provided as separate devices, and the present invention can be completed with only the recording systems 1 to 3°4', 5 to 6, and 13 at the bare minimum.
第1図は従来の磁気鍮画再生装置における輝度信号の信
号処理系統図、第2図は従来の記録等化特性の1例、第
3図はVH8−VTRにおける輝度信号の周波数アロケ
ーションを示す図、第4図は輝度信号のAPLが黒レベ
ルに近いものと白レベルに近いものの例、第5図は従来
の再生等化特性、第6図は本発明の1実施例を示すブロ
ック図、第7図は本発明の記録等化回路の11施例であ
る。
1・・・ローパスフィルタ、2・・・エンファシス回路
、3・・・FM変調回路、4.4’・・・記録等価回路
、5・・・記録アンプ、6・・・磁気ヘッド、磁気テー
プ、8・・・再生アンプ、9・・・再生等化回路、10
・・・リミッタ回路、11・・・FM復調回路、12・
・・デイエンフVJ、 I 図
篤 Z 図
1Z31L56”#
lfl這数[Mfh]
第 3 図
34輛Hz
Il:J4 図
第 5 図
周仮数(MHz)Fig. 1 is a signal processing system diagram of luminance signals in a conventional magnetic brass picture reproduction device, Fig. 2 is an example of conventional recording equalization characteristics, and Fig. 3 is a diagram showing frequency allocation of luminance signals in a VH8-VTR. , FIG. 4 shows examples of brightness signals with APL close to black level and white level, FIG. 5 shows conventional reproduction equalization characteristics, and FIG. 6 is a block diagram showing one embodiment of the present invention. FIG. 7 shows 11th embodiment of the recording equalization circuit of the present invention. DESCRIPTION OF SYMBOLS 1... Low pass filter, 2... Emphasis circuit, 3... FM modulation circuit, 4.4'... Recording equivalent circuit, 5... Recording amplifier, 6... Magnetic head, magnetic tape, 8... Reproduction amplifier, 9... Reproduction equalization circuit, 10
...Limiter circuit, 11...FM demodulation circuit, 12.
... Dayenfu VJ, I Z Atsushi Z Figure 1 Z31L56"# lfl number [Mfh] No. 3 Figure 34 Hz Il: J4 Figure No. 5 Figure mantissa (MHz)
Claims (1)
気録画装置において、該輝度信号の平均1儂レベルに応
じて周波数特性を変化させる等化回路を設は前記輝度信
号t−蚊等化回路を介して磁気録画するごとく構成した
ことを特徴とする磁気録画装置。 2、特許請求の範囲第1項記載の磁気録画装置において
、録画され良輝度信号を他の等化回路を介し、FM復調
する再生回路を具備してなる磁気録画装置。[Claims] 1. In a magnetic recording device that performs magnetic recording by performing t-FM modulation on a luminance signal during recording, an equalization circuit that changes the frequency characteristic according to the average level of the luminance signal is provided. A magnetic recording device characterized in that it is configured to perform magnetic recording via a signal t-mosquito equalization circuit. 2. A magnetic recording apparatus according to claim 1, comprising a reproducing circuit for FM demodulating the recorded high-luminance signal via another equalizing circuit.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP57036415A JPS58155508A (en) | 1982-03-10 | 1982-03-10 | Magnetic video recorder |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP57036415A JPS58155508A (en) | 1982-03-10 | 1982-03-10 | Magnetic video recorder |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS58155508A true JPS58155508A (en) | 1983-09-16 |
JPH0413786B2 JPH0413786B2 (en) | 1992-03-10 |
Family
ID=12469193
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP57036415A Granted JPS58155508A (en) | 1982-03-10 | 1982-03-10 | Magnetic video recorder |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS58155508A (en) |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5091310A (en) * | 1973-12-12 | 1975-07-22 | ||
JPS553528U (en) * | 1978-06-20 | 1980-01-10 |
-
1982
- 1982-03-10 JP JP57036415A patent/JPS58155508A/en active Granted
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5091310A (en) * | 1973-12-12 | 1975-07-22 | ||
JPS553528U (en) * | 1978-06-20 | 1980-01-10 |
Also Published As
Publication number | Publication date |
---|---|
JPH0413786B2 (en) | 1992-03-10 |
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