JPH0127328Y2 - - Google Patents
Info
- Publication number
- JPH0127328Y2 JPH0127328Y2 JP1982076813U JP7681382U JPH0127328Y2 JP H0127328 Y2 JPH0127328 Y2 JP H0127328Y2 JP 1982076813 U JP1982076813 U JP 1982076813U JP 7681382 U JP7681382 U JP 7681382U JP H0127328 Y2 JPH0127328 Y2 JP H0127328Y2
- Authority
- JP
- Japan
- Prior art keywords
- output
- frequency
- oscillator
- carrier wave
- filter
- 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.)
- Expired
Links
Landscapes
- Cooling Or The Like Of Electrical Apparatus (AREA)
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
Description
【考案の詳細な説明】
本考案は、表面弾性波型VSBフイルター
（SAW VSBフイルター）を使用したテレビジヨ
ン映像送信装置に関し、特に表面弾性波フイルタ
ーの温度特性を補償する技術に関する。[Detailed Description of the Invention] The present invention relates to a television video transmission device using a surface acoustic wave VSB filter (SAW VSB filter), and particularly relates to a technique for compensating for the temperature characteristics of the surface acoustic wave filter.
最近、テレビジヨン送信装置において、従来の
集中定数型、もしくは分布定数型VSBフイルタ
ーにかわり、SAW VSBフイルターが実用化さ
れ多く使用されている。SAW VSBフイルター
は従来のものに比較し位相平担特性を有するので
振巾周波数特性上の急峻な遮断特性に起因するグ
ループデイレー特性の補償を必要としない利点を
有する。しかしながら、SAWフイルターは周知
の如く構成される基板材料の温度特性により、周
囲温度に対し、帯域特性が周波数軸上で平行に変
動する。現在最も多く使用されているリチウムナ
イオベート（LiNbO3）基板を使用した場合帯域
特性の中心周波数0は周囲温度に対し85PPM／
℃の割合で変動する。 Recently, SAW VSB filters have been put into practical use and are widely used in television transmitting equipment instead of conventional lumped constant or distributed constant VSB filters. Compared to conventional filters, the SAW VSB filter has a phase-flattening characteristic, so it has the advantage of not requiring compensation for group delay characteristics caused by steep cut-off characteristics in amplitude frequency characteristics. However, as is well known, the band characteristics of the SAW filter vary in parallel on the frequency axis with respect to the ambient temperature due to the temperature characteristics of the substrate material. When using a lithium niobate (LiNbO 3 ) substrate, which is currently the most commonly used substrate, the center frequency 0 of the band characteristic is 85 PPM/
It fluctuates at a rate of ℃.
一方、テレビジヨン送信装置に使用される
VSBフイルターの特性の許容範囲は、その一例
を第１図に示す如く非常に小さく、周囲温度−10
℃〜＋50゜を考慮すると、SAW VSBフイルター
の温度特性による変動分は上記許容範囲を満足す
ることが出来ない。そのため、通常SAW VSB
フイルターを55℃〜60℃に保たれている恒温槽内
に実装し、この温度特性による変動分を最少にし
ている。 On the other hand, used in television transmitting equipment
The permissible range of VSB filter characteristics is very small, as shown in Figure 1.
Considering the range from ℃ to +50°, the variation due to the temperature characteristics of the SAW VSB filter cannot satisfy the above tolerance range. Therefore, typically SAW VSB
The filter is mounted in a constant temperature chamber maintained at 55℃ to 60℃ to minimize fluctuations due to temperature characteristics.
上記恒温槽方式は高温の中に部品を実装さねば
ならず信頼度が落ちる欠点を有し又送信機起動時
もしくは恒温槽電源投入時恒温槽内の温度が所定
の温度に達する迄に時間を要し、この間第１図に
示す周波数特性の許容範囲を満足しない恐れがあ
る。 The thermostatic oven method described above has the drawback of lowering reliability because the components must be mounted in high temperatures, and it takes time for the temperature inside the thermostatic oven to reach a predetermined temperature when the transmitter is started or when the thermostatic oven power is turned on. Therefore, during this time, there is a possibility that the permissible range of frequency characteristics shown in FIG. 1 may not be satisfied.
第２図は従来使用されているテレビジヨン映像
送信機の基本構成を示す。すなわち、映像変調器
１において、IF搬送波発振器４の出力であるIF
搬送波IFを映像入力信号で変調し、両側波帯被
変調信号を得る。この被変調波をSAW VSBフ
イルター２により所要のVSB特性を持たせ、周
波数変換器３において局部発振器５の出力である
局部周波数LOとミキシングし所要の最終出力V
（＝LO−IF）を得る。尚、本図では局部周波数
LOはV＋IFに選んであるが、場合によつてはLO
はV−IFに選び周波数変換器で上側波帯成分を
得て所要のVを得ることもある。第２図の基本構
成ではSAW VSBフイルターは恒温槽内に実装
されている。 FIG. 2 shows the basic configuration of a conventionally used television video transmitter. That is, in the video modulator 1, the IF which is the output of the IF carrier wave oscillator 4
Modulate the carrier wave IF with the video input signal to obtain a double-sided band modulated signal. This modulated wave is given the required VSB characteristics by the SAW VSB filter 2, and mixed with the local frequency LO which is the output of the local oscillator 5 in the frequency converter 3 to obtain the required final output V.
(= LO − IF ) is obtained. In addition, in this figure, the local frequency
LO is chosen to be V + IF , but in some cases LO
may be selected as V − IF and obtain the upper sideband component using a frequency converter to obtain the required V. In the basic configuration shown in Figure 2, the SAW VSB filter is mounted inside a constant temperature chamber.
本考案の目的は、上述の恒温槽を使用すること
の欠点を除去し、簡単な補償用発振器を設けるこ
とにより容易にSAW VSBフイルターの温度特
性による変動分を補償するテレビジヨン映像送信
装置を提供することである。 The purpose of the present invention is to provide a television video transmitter that eliminates the disadvantages of using a thermostatic oven as described above and easily compensates for fluctuations due to the temperature characteristics of a SAW VSB filter by providing a simple compensation oscillator. It is to be.
本考案によれば、SAW VSBフイルターの近
傍の周囲温度を検知し、この検知出力により周波
数を制御される補償用発振器を設けこの出力を映
像IF搬送波と混合し、これを映像変調器へのIF
搬送波とすることによりSAW VSBフイルター
の周波数特性が周囲温度により変動してもこれに
応じてこの変動分だけIF搬送波も同じ方向へ変
動させることにより所要のVSB特性を維持させ
るものである。又、これに加えて上記補償用発振
器の出力を更に局部発振器出力に混合しSAW
VSBフイルターの変動と逆の方向に変動させこ
れを周波数変換器で上記SAW VSBフイルター
を通過したIF搬送波と混合させることにより補
償用発振周波数を相殺し、所要の最終出力周波数
を得るものである。尚、該補償用発振器は
LiNbO3基板を使用したSAW VSBフイルターの
場合は、周囲温度が低い方へずれたとき、これに
対応して帯域特性の中心周波数が高い方へずれる
為この中心周波の変動分と同じだけ、周波数を高
い方へ制御する。又、この補償用発振器は周波数
の安定度自体は最終出力周波数に影響を与えるこ
とがなく、非常に簡易なものでよい利点も有す
る。 According to the present invention, the ambient temperature near the SAW VSB filter is detected, a compensation oscillator whose frequency is controlled by the detection output is provided, the output is mixed with the video IF carrier wave, and this is sent to the IF to the video modulator.
By using a carrier wave, even if the frequency characteristics of the SAW VSB filter fluctuate due to ambient temperature, the IF carrier wave is also changed in the same direction by the amount of this fluctuation, thereby maintaining the required VSB characteristics. In addition to this, the output of the above compensation oscillator is further mixed with the local oscillator output to generate SAW.
The oscillation frequency for compensation is offset by changing the frequency in the opposite direction to the fluctuation of the VSB filter and mixing it with the IF carrier wave that has passed through the SAW VSB filter using a frequency converter, thereby obtaining the desired final output frequency. In addition, the compensation oscillator is
In the case of a SAW VSB filter using a LiNbO 3 substrate, when the ambient temperature shifts to a lower side, the center frequency of the band characteristic shifts to a higher side correspondingly, so the frequency increases by the same amount as the fluctuation in this center frequency. control to a higher level. Further, this compensation oscillator has the advantage that the frequency stability itself does not affect the final output frequency, and it can be very simple.
本考案の特徴は補償用発振器を設けることによ
り容易にSAW VSBフイルターの温度特性によ
る周波数変動分を補償出来ることである。尚、本
考案の延長として補償発振器出力の混合は映像変
調器出力及びSAW VSBフイルター出力の部分
でそれぞれ行うことも原理的には可能であるが、
技術的に所要帯域内に不要周波数成分が落ち込む
ことがあり現実的でない。 A feature of the present invention is that by providing a compensation oscillator, it is possible to easily compensate for frequency fluctuations due to the temperature characteristics of the SAW VSB filter. As an extension of the present invention, it is theoretically possible to mix the compensation oscillator output at the video modulator output and the SAW VSB filter output.
Technically speaking, this is not practical because unnecessary frequency components may fall within the required band.
次に、第３図に本考案の一実施例を示し、本考
案を詳細に説明する。第３図において、映像変調
器１において、IF搬送波を映像入力信号で変調
し両側波帯被変調信号を得ることは、従来と同じ
であるが、SAW VSBフイルター２の近傍の周
囲温度を検知する温度検知回路６を有し、この検
知出力で補償用発振器７を制御し、この周波数出
力を２分配器８で分配し、この一つの出力COMP
とIF搬送波発振器４の出力IFをミキサー９で混
合し、この出力（IF＋COMP）を映像変調器１の
IF搬送波入力とする。この映像変調器１の出力
信号はSAW VSBフイルター２に入力し所要の
VSB特性を得た出力信号は周波数変換器３で所
要の最終出力周波数に変換されることになるがこ
の周波数変換に必要な局部発振周波数は局部発振
器５の出力LOと前記補償用発振器出力COMPとミ
キサー１０で混合したLO−IFが入力されること
になる。したがつて周波数変換器３の出力は所要
の最終周波数V＝LO−IFを得ることが出来る。 Next, FIG. 3 shows an embodiment of the present invention, and the present invention will be explained in detail. In FIG. 3, the video modulator 1 modulates the IF carrier wave with the video input signal to obtain a double-sided band modulated signal, which is the same as before, but the ambient temperature near the SAW VSB filter 2 is detected. It has a temperature detection circuit 6, this detection output controls a compensation oscillator 7, this frequency output is divided by a two-way divider 8, and this one output COMP
and the output IF of the IF carrier wave oscillator 4 are mixed in the mixer 9, and this output ( IF + COMP ) is sent to the video modulator 1.
IF carrier wave input. The output signal of this video modulator 1 is input to the SAW VSB filter 2 and the required signal is input to the SAW VSB filter 2.
The output signal with the VSB characteristic is converted to the required final output frequency by the frequency converter 3, but the local oscillation frequency required for this frequency conversion is determined by the output LO of the local oscillator 5 and the compensation oscillator output COMP . The LO - IF mixed by the mixer 10 will be input. Therefore, the output of the frequency converter 3 can obtain the required final frequency V = LO - IF .
以上、本考案の構成作用動作及び実施例に関
し、詳細に説明した通り本考案によれば非常に簡
易な回路でSAW VSBフイルターの温度特性に
よる周波数特性の変動を補償することが出来る。 As described above in detail regarding the configuration, operation, and embodiments of the present invention, according to the present invention, it is possible to compensate for fluctuations in frequency characteristics due to temperature characteristics of a SAW VSB filter with a very simple circuit.
第１図はテレビジヨン映像送信装置に使用され
るVSBフイルターに要求される振巾周波数特性
の一例を示す。第２図は従来使用されているテレ
ビジヨン映像送信装置の基本構成を示す図、第３
図に本考案の一実施例を示す図。
図において、１……映像変調器、２……SAW
VSBフイルター、３……周波数変換器、４……
IF搬送波発振器、５……局部発振器、６……温
度検知回路、７……補償用発振器、８……２分配
器、９……ミキサー、１０……ミキサー。
FIG. 1 shows an example of the amplitude frequency characteristics required of a VSB filter used in a television video transmitter. Figure 2 is a diagram showing the basic configuration of a conventionally used television video transmitter;
The figure shows one embodiment of the present invention. In the figure, 1...video modulator, 2...SAW
VSB filter, 3... Frequency converter, 4...
IF carrier wave oscillator, 5...Local oscillator, 6...Temperature detection circuit, 7...Compensation oscillator, 8...2 divider, 9...Mixer, 10...Mixer.
Claims (1)
器と、前記変調器の出力を受ける表面弾性波型
VSBフイルターと、前記フイルターの温度を検
知する温度検知器と、前記温度検知器の出力に応
じて周波数が変わる温度補償信号を発振する補償
用発振器と、搬送波用の発振器と、前記搬送波用
の発振器の出力と前記温度補償信号とを周波数混
合して前記第１の搬送波を出力する第１の混合器
と、局部発振出力を出力する局部発振器と、前記
局部発振出力と前記温度補償信号とを周波数混合
して第２の局部発振信号を作る第２の混合器と、
前記フイルターの出力を受け前記第２の局部発振
信号により周波数変換する周波数変換器とを具備
し、前記第１及び第２の混合器における前記温度
補償信号の関与を相補的にしたこととを特徴とす
るテレビジヨン映像送信装置。 a modulator that modulates a first carrier wave according to video input; and a surface acoustic wave type that receives the output of the modulator.
a VSB filter, a temperature sensor that detects the temperature of the filter, a compensation oscillator that oscillates a temperature compensation signal whose frequency changes depending on the output of the temperature sensor, a carrier wave oscillator, and a carrier wave oscillator. a first mixer that frequency-mixes the output of the oscillator and the temperature compensation signal to output the first carrier wave; a local oscillator that outputs a local oscillation output; a second mixer for mixing to produce a second local oscillator signal;
and a frequency converter that receives the output of the filter and converts the frequency using the second local oscillation signal, and the temperature compensation signal is complementary to the contribution of the temperature compensation signal in the first and second mixers. Television video transmission equipment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7681382U JPS58178764U (en) | 1982-05-25 | 1982-05-25 | Television video transmitter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7681382U JPS58178764U (en) | 1982-05-25 | 1982-05-25 | Television video transmitter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58178764U JPS58178764U (en) | 1983-11-30 |
| JPH0127328Y2 true JPH0127328Y2 (en) | 1989-08-15 |
Family
ID=30086107
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7681382U Granted JPS58178764U (en) | 1982-05-25 | 1982-05-25 | Television video transmitter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58178764U (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2890195B2 (en) * | 1987-11-06 | 1999-05-10 | 和彦 山之内 | Temperature compensation method of surface acoustic wave matched filter |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5595471A (en) * | 1979-01-16 | 1980-07-19 | Toshiba Corp | Television broadcast unit |
| JPS6128449Y2 (en) * | 1980-02-18 | 1986-08-23 |
-
1982
- 1982-05-25 JP JP7681382U patent/JPS58178764U/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58178764U (en) | 1983-11-30 |
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