GB2322747A - TV receiver with temperature compensation to frequency response of lithium niobate SAW filter by means of tuner or equaliser - Google Patents
TV receiver with temperature compensation to frequency response of lithium niobate SAW filter by means of tuner or equaliser Download PDFInfo
- Publication number
- GB2322747A GB2322747A GB9802175A GB9802175A GB2322747A GB 2322747 A GB2322747 A GB 2322747A GB 9802175 A GB9802175 A GB 9802175A GB 9802175 A GB9802175 A GB 9802175A GB 2322747 A GB2322747 A GB 2322747A
- Authority
- GB
- United Kingdom
- Prior art keywords
- temperature
- tuner
- characteristic
- surface acoustic
- 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
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
- H04N5/4446—IF amplifier circuits specially adapted for B&W TV
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
- H03J3/00—Continuous tuning
- H03J3/02—Details
- H03J3/04—Arrangements for compensating for variations of physical values, e.g. temperature
Abstract
A video signal reproducing circuit comprises at least a tuner (1) for receiving a broadcast signal and frequency-converting it into an intermediate frequency signal, a surface acoustic wave filter (2) using a lithium niobate substrate electrically connected to the output side of the tuner, and a video equalizer (4) electrically connected to the output side of the surface acoustic wave filter via a detection integrated circuit (3). The tuner has a temperature-frequency characteristic or the tuner and the video equalizer have temperature-frequency characteristics to compensate a temperature-frequency characteristic of the surface acoustic wave filter.
Description
2322747 VIDEO SIGNAL REPRODUCING CIRCUIT
This invention relates to a video signal reproducing circuit, and particularly to a video signal reproducing circuit where 4 n when a television broadcast signal is received to reproduce a video signal, a surface acoustic wave (SAW) filter using a lithium niobate (LiNb03) is electrically corrected to the output side of a tuner, whereby the entire circuit configuration thereof is sim-olified and hence its manufacturing cost is lowered. Description of the Related Art:
As a video signal -reproducing circuit for receiving a broadcast signal therein and thereby reproducing a video signal, one has heretofore been known which has a configuration wherein a surface acoustic wave (SAW) filter using a lithium tantalate (LiTa03) substrate is -put side of a tuner to electrically connected to the out extract an intermediate frequency signal outputted from the tuner.
Fig. 5 is a block diagram showing one example of a configuration of such an already-known video signal reproducing circuit.
As shown in Fig. 5, the known video signal reproducing circuit comprises a tuner 51 for receiving a television broadcast signal therein and frequency-converting it into an intermediate frequency signal, a surface acoustic wave (SAW) filter 53 using a lithium tantalate (LiTa03) 1 substrate electrically connected to the output side of the tuner 51 via an intermediate frequency amplifier 52, a detection integrated circuit (IC) 55 electrically connected to the outpu-- side of 'the surface acoustic wave filter 53 through an impedance matching coil 54, and a video equalizer 56 electrically connected to the Output side of the detection integrated circuit 55.
In this case, the intermediate frequency amplifier 52 is used to compensate for a comparatively large loss of an intermediate frequency signal generated from the surface acoustic wave filter 53. The impedance matching coil 54 is used to match high out-out impedance of the surface acoustic wave filter 53 to low 4 nput impedance of the detection integrated circuit 55.
In the video signal reproducing circuit having such a construction, the tuner 51 converts a television broadcast signal received by an antenna (not shown) into an intermediate frequency signal and outputs it therefrom. The intermediate frequency amplifier 52 amplifies the intermediate frequency signal and outputs it therefrom. The surface acoustic wave filter 53 extracts a required intermediate frequency signal from the amplified intermediate frequency signal. The impedance matching coil 54 effects impedance conversion on the extracted required intermediate frequency signal. The detection integrated circuit 55 detects the required intermediate frequency signal and outputs a video signal therefrom. The video equalizer circuit 56 performs predetermined frequency equalization on the video signal.
- 2 meanwhile, the surface acoustic wave filter 53 using the lithium tantalate substrate employed in the alreadyknown video signal reproducing circuit has an advantage in that it can be used without particular addition of a temperature compensating circuit thereto because it comparatively satisfactory in temperature-frecruency characteristic. However, the surface acoustic wave filter 53 is comparatively expensive, comparatively large in signall loss within a signal passband and comparatively high in input/output impedance. Therefore, the alreadyknown video signal reproducing circuit using the surface acoustic wave filter 53 used with the lithium tantalate substrate necessitates that the intermediate frequency amplifier 52 Js electrically connected to a stage prior to the surface acoustic wave filter 53 to compensate for a signal loss produced within the signal passband and the impedance matching coil 54 is electrically connected to a stage posterior to the surface acoustic wave filter 53 to match the high output impedance of the surface acoustic wave filter 53 to the low input impedance of the detection integrated circuit 555.
Thus, the known video signal reproducing circuit using the surface acoustic wave filter 53 that makes use of the lithium tantalate substrate, has a problem in that since the intermediate frequency amplifier 52 and the impedance matching coil 54 are electrically connected to the surface acoustic wave filter 53, the video signal reproducing circuit becomes complex not only in configuration but also 7 3 expensive in manufacturing cost in combination with the expansiveness of the surface acoustic filter 53 itself.
With the foregoing in view, it is therefore an object of the present invention to provide a video signal reproducing circuit wherein an inexpensive surface acoustic wave filter is used and a simple circuit is utilized to compensate for a comparatively large temperature-frequency characteristic thereof, whereby its overall configuration can be simplified and its manufacturing cost can be reduced.
According to one aspect of the present invention, for achieving the above object, there is provided a video signal reproducing circuit according to the present invention, which is equipped with a first means wherein a surface acoustic wave filter using a lithium niobate substrate is used as a surface acoustic wave filter and a tuner is caused to have a temperature-frequency characteristic opposite to a temperature-frequency characteristic of the surface acoustic wave filter to cancel the temnerature-frequency characteristic of the surface acoustic wave filter.
According to another aspect of the present invention, for achieving the above object, there is provided a video signal reproducing circuit according to the present invention, which is equipped with a second means wherein a surface acoustic wave filter using a lithium niobate substrate is used as a surface acoustic wave filter, and a 4 tuner and a video equalizer circuit are respectively caused to have temperature-frequency characteristics opposite to a _emperature-frequency characteristic of the surface acoustic wave filter as a whole to cancel the temiDeraturefrequency characteristic thereof.
According to the first and second means, since the surface acoustic wave filter using the lithium niobate subszrate low in cost and -input/output impedance is used, i- is unnecessary to provide an intermediate frequency the surface am-olifier for comiDensating for a signal loss of acoustic wave filter employed in this type of known circuit and an impedance matching coil for performing impedance mT atching. Thus, the video signal reproducing circuit is simplified in circuit configuration and is reduced in. manufacturing cost over its entirety.
Further, according to the first and second means, the temperaturefrequency characteristic of the surface acoustic wave filter using the lithium niobate substrate is compensated by the tuner having the temperature-frequency characteristic opposite to the temperaturefrequency characteristic thereof or both the tuner and the video ecrualizer circuit each having the temperature- f recruency cliaracteristic opposite to the temperature-frequency characteristic of the surface acoustic wave filter to thereby cancel the entire temperaturefrequency characteristic of the video signal reproducing circuit.
In one embodiment of the present invention, a video signal reproducing circuit comprises at least a tuner for receiving a broadcast signal therein and frequency- 7 5 converting the broadcast signal into an intermediate frequency signal, and a surface acoustic wave filter using a lithium niobate substrate electrically connected to the output side of the tuner. Thus, the tuner is allowed to t 4 have a temperature-frequency characteris Lc and hence a temperature- frequency characteristic of the surface acoustic wave filter is canceled by the temperaturefrequency characteristic of the tuner.
In another embodiment of the present invention, a video signal reproducing circuit comprises at least a tuner for receiving a broadcast signal therein and frequencyconverting the broadcast signal into an intermediate frequency signal, a surface acoustic wave filter using a lithium niobate substrate electrically connected to the output side of the tuner, and a video equalizer circuit electrically connected to the output side of the surface acoustic wave filter via a detection integrated circuit. Thus, the tuner and the video equalizer circuit are caused to have temperature-frequency characteristics respectively and hence a temperature-frequency characteristic of the surface acoustic wave filter is canceled by these temperature-frequency characteristics.
In specific examples of these embodiments, the tuner is caused to have a temperature-frequency characteristic by means of a temperature-dependent type intermediate frequency resonance circuit. Preferably, a capacitor having a temperature-capacitance characteristic is employed in the temperature-dependent type intermediate frequency resonance circuit.
According to an embodiment of the present invention, since the surface acoustic wave filter using the lithium niobate substrate low in cost and input/output impedance is utilized as the surface acoustic wave filter for extracting the required intermediate frequency signal, the intermediate frequency an-plifier for compensating for the signal loss of the surface acoustic wave filter and the impedance matching coil for ma- _ching the impedance of the surface acoustic wave filter to that of the next-stage detection integrated circuit, both of which are employed in the already-known video signal reproducing circuit, are omitted. Therefore, the video signal reproducing circuit can be simplified in circuit configuration over its entirety and the manufacturing cost of the video signal reproducing circuit can be lowered in cooperation with the use of the surface acoustic wave filter using the inexpensive lithium niobate substrate.
According to an embodimeni of the present invention as well, since the tuner or each of the tuner and the video equalizer circuit is allowed to have the temperaturefrequency characteristic opposite to the temperaturefrequency characteristic of the surface acoustic wave filter using the lithium niobate substrate and thereby the temperature-frequency characteristic of the surface acoustic wave filter is canceled by the opposite temperature-frequency characteristic, the overall temperaturefrequency characteristic of the video signal reproducing circuit is eliminated, whereby the bandwidth of the video signal can be prevented from varying with a change in ambient temperature.
Typical ones of various inventions of the present application have been shown in brief. However, the various inventions of the present application and specific config-urations of these inventions will be understood from L-he following description.
while the snecification concludes with claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention, it j believed that the invention, the objects and features of the invention and further objects, features and advantages thereof will be better understood from the following description taken in connection with the accompanying drawings in which:
Fig. 1 is a block diagram showing a config-uration of one embodiment of a video signal reproducing circuit according to the present invention; Figs. 2A to 2D are circuit diagrams illustrating an example of a configuration of an output portion of a tuner employed in the video signal reproducing circuit shown in Fig-. 1; Figs. 3A and 3B are characteristic diagrams depicting respective examples of temperature-frequency characteristics of a surface acoustic wave filter and the tuner employed in the video signal reproducing circuit shown in Fig. 1; Figs. 4A and 4B are circuit diagrams showing examples of a configuration of a video equalizer circuit employed in the video signal reproducing circuit shown in Fig. 1; and Fig. 5 is a block circuit diagram illustrating one example of a configuration of a conventional video signal reproducing circuit.
Preferred embodiments of the present invention will hereinafter be described with reference to the accompanying drawings.
Fig. 1 is a block diagram showing a configuration of one embodiment of a video signal reproducing circuit according to the present invention.
As shown in Fig. 1, the video signal reproducing circuit according to the present embodiment com-orises a tuner 1 for receiving a television broadcast signal therein, frequency-converting it into an intermediate frequency signal and outputting it therefrom, a surface acoustic wave (SAW) filter 2 using a lithium niobate (LiNb03) substrate electrically connected to the output side of the tuner 1, a detection integrated circuit (IC) 3 electrically connected to the output side of the surface acoustic wave filter 2, a video equalizer circuit 4 electrically connected to the output side of the detection integrated circuit 3, and a video signal output terminal 5 electrically connected to an output terminal (not shown) of the video equalizer circuit 4.
- 9 In this case, as will be described below in detail, one having a comparatively large temperature vs. frequency characteristic opposit:e to a comparatively large temperature vs. frequency characteristic exhibited by the surface acoustic wave filter 2 is used as the tuner 1.
Fig. 2A is a block configurational diagram showing one example of a configuration of an output portion of the tuner 1 shown in Fig. 1. Figs. 2B through 2D are respectively circuit diagrams showing other configurational examples of the temperature-dependent type intermediate frequency resonance circuit shown in Fig. 2A.
As illustrated in Fig. 2A, the output portion of the tuner 1 comprises a local oscillator 6 for outputting a local oscillation signal having a frequency corresponding to a tuned television broadcast signal frequency, a frequency mixer 7 for frequency-mixing the received television broadcast signal and the local oscillation signal, a temperature- dependent type intermediate frequency resonance circuit 8 tuned to an intermediate frequency and having a temperature-frequency characteristic, and an intermediate frequency signal output amplifier 9.
In the case of the example shown in Fig. 2A in this case, one of a type wherein a parallel circuit made up of a coil 10 and a capacitor 11 having a temperature-capacitance characteristic is electrically connected between a signal transmission path and a ground point, is used as the temperature-dependent type intermediate frequency resonance circuit 8.
- 10 Further, Fig. 3A shows a signal pass characteristic of the surface acoustic wave filter 2 using the lithium niobate substrate. Fig. 3B illustrates a pass characteristic exhibited by the temperature-dependent type -ie tuner 1.
intermediate frequency resonance CL--CUit 8 of tII Referring to Figs. 3A and 3B, the vertical axes and the horizontal axes indicate signal levels and frequencies respectively. Further, the solid lines indicate characteristics obtained at an ordinary temperature (of 25'C, for example) and the dashed lines indicate characteristics obtained at a high temperature (of 55'C, for examnle).
The operation of the video signal reproducing circuit according to the present embodiment, which is constructed exolained with 3A and 3B. broadcast signal and amplifies the received television broadcast signal by means of a high frequency amplifier (not shown). Next, the frequency mixer 7 mixes the local oscillation signal supplied from the local oscillator 6 with the amr:)lified television broadcast signal to generate a frequency-mixed signal. Further, the temperature-dependent type intermediate frequency resonance circuit 8 extracts an intermediate frequency signal from the frequency-mixed signal supplied thereto according to the intermediate frequency signal bandpass characteristic indicated by the solid line in Fig. 3B. Thereafter, the intermediate frequency signal output amplifier 9 amplifies in the above-described manner, will be reference to Fig. 1, Fig. 2A and Figs.
The tuner 1 receives a television through a receiving antenna (not shown) 11 - the extracted intermediate frequency signal to a predetermined level and supplies it to the next-stage surface acoustic wave filter 2.
The surface acoustic wave filter 2 extracts an intermediate frequency signal having frequency components required according to the intermediate frequency signal bandpass characteristic indicated by the solid line in Fig. 3A from the intermediate frequency signal supplied from the tuner 1 and supplies it to the next-stage detection integrated circuit 3. The detection integrated circuit 3 detects the intermediate frequency signal supplied thereto to thereby reproduce a video signal and supplies the reproduced video signal to the next-stage video equalizer circuit 4. The video equalizer circuit 4 effects required frequency-response equalization on the video signal supplied thereto and supplies it to the video signal output terminal 5.
When the temperature to be used is an ordinary temperature (of 15'C, for example) or close to the ordinary temperature in this case, the intermediate frequency signal bandpass characteristic indicated by the solid line in Fig. 3A, of the surface acoustic wave filter 2 using the lithium niobate substrate is substantially superimposed on the intermediate frequency signal bandpass characteristic indicated by the solid line in Fig. 3B, of the temperaturedependent type intermediate frequency resonance circuit 8. The resultant bandpass characteristic of video signal results in one that depends on the intermediate frequency 12 signal bandpass characteristic indicated by the solid line in Fig. 3A, of the surface acoustic wave filter 2.
When, on the other hand, the temperature to be used becomes a temperature (of e.g., 55'C) higher than the ordinary temperature or becomes close to the ordinary l-emperature, the intermediate frequency signal bandpass characteristic of the surface acoustic wave filter 2 is changed or transitioned to a low frequency as a whole as indicated by the dashed line in Fig. 3A. Since, at this time, the temperature-dependent type intermediate frequency resonance circuit 8 makes use of the capacitor 11 having a negative temperature-capacitance characteristic and allows its inter-mediate frequency signal bandpass characteristic to transition or shift to a high frequency as a whole as indicated by the dashed line in Fig. 3B, the temperaturefrequency characteristic of the surface acoustic wave filter 2 and that of the temperature-dependent type intermediate frequency resonance circuit 8 cancel each other. Thus, the frequency response of a video signal obtained at the video signal output terminal 5 can be held substantially constant without regard to a change in temperature to be used.
Further, when the temperature to be used reaches a temperature (of e.g., 10'C) lower than the ordinary temperature or becomes close to the ordinary temperature, the entire frequency transition of the intermediate frequency signal bandpass characteristic of the surface acoustic wave filter 2 and the entire frequency transition of the intermediate frequency signal band-pass 13 characteristic of the temperature-dependent type intermediate frequency resonance circuit 8 are respectively reversed in direction as compared with the case where the temperature to be used has reached the temperature higher than the ordinary temperature. However, the temperaturefrequency characteristic of the surface acoustic wave filter 2 and the temperature-frequency characteristic of the temperature-dependent type intermediate frequency resonance circuit 8 cancel each other. Thus, the frequency characteristic of a video signal obtained at the video signal output terminal 5 can be kept substantially constant without regard to any change in temperature to be used.
Although the aforementioned embodiment has described the case where one in which the parallel circuit comprised of the coil 10 and the capacitor 11 having the positive temperature-capacitance characteristic is electrically shunt-connected between the signal transmission path and the ground point, is used as the temperature-dependent type intermediate frequency resonance circuit 8, the example of the configuration of the temperature-dependent type intermediate frequency resonance circuit 8 is not necessarily limited to one illustrated in Fig. 2A. As an alternative to this, one wherein a parallel circuit comprised of a coil 10, a capacitor 11 having a positive temperature-capacitance characteristic and a resistor 12 is electrically shunt-connected between a signal transmission path and a ground point as shown in Fig. 2B, one wherein a parallel circuit comprised of a coil 10 and a capacitor 11 having a negative temperature-capacitance characteristic is electrically series-connected to a signal transmission path as shown in Fig. 2C, and one wherein a parallel circuit comprised of a coil 10, a capacitor 11 having a negative temperature-caipacitance characteristic and a resistor 12 is electrically series-connected to a signal transmission path may be used.
Further, the aforementioned embodiment shows the case in which the temnerature-frecruency characteristic of the surface acoustic filter 2 is canceled by the reverse temperature-frequency characteristic of the temperaturedependent type intermediate frequency resonance circuit 8. However, the present embodiment may be constructed and modified as another embodiment in such a manner that the video equalizer circuit 4 is also allowed to have the temperature-frequency characteristic in a manner similar to the temperature-dependent type intermediate frequency resonance circuit 8 in addition to the temperaturedependent type intermediate frequency resonance circuit 8, and the temperature-frequency characteristic of the surface acoustic filter 2 is canceled by the synthetic temperaturefrequency characteristic of the temperaturefrequency characteristic of the temperature-dependent type intermediate frequency resonance circuit 8 and the temperature-frequency characteristic of the video equalizer circuit 4.
Figs. 4A and 4B are respectively circuit diagrams showing examples of configurations of the video equalizer circuit 4 having the temperaturefrequency characteristic, which is employed in another embodiment.
In another embodiment, for examule, one in which a series circuit comprised of a coil 13, a capacitor 14 having a negative temperaturecapacitance characteristic and a resistor 15 is electrically shuntconnected between a signal transmission path and a ground point as shown in Fig. 4A or one in which a parallel circuit comprised of a coil 13 and a resistor 15 is electrically series-connected to a signal transmission path and a capacitor 14 having a negative temperature-capacitance characteristic is electrically connected between the signal transmission path and a ground point, is used as the video equalizer circuit 4.
Since the operation of another embodiment conforms to that of the aforementioned embodiment and the resultant advantageous effect is based on that of the above-described embodiment, the description of its detailed operation and effect will be omitted. However, according to another embodiment, since the temperature-frequency characteristic of the surface acoustic filter 2 is canceled by the synthetic or total temperature-frequency characteristic of the temperature-frequency characteristic of the temperature-dependent type intermediate frequency resonance circuit 8 and the temperature-frequency characteristic of the video equalizer circuit 4, the temperature-dependent type intermediate frequency resonance circuit 8 and the video equalizer 4 can be provIded with the freedom of design.
While the present invention has been described with reference to the illustrative embodiments, this description
16 - various well as other embodiments is not intended to be construed in a limiting sense.
modificatL.ons of the illustrative embodiments, as of the invention, will be apparent to those skilled in the art on reference to this description. It is therefore contemplated that the appended claims will cover any such modifications or embodiments as -Fall within the true scoiDe of the invention.
17 -
Claims (7)
1. A video signal reproducing circuit comprising at least:
a tuner for receiving a broadcast signal therein and frequency-converting the broadcast signal into an intermediate frequency signal; and a surface acoustic wave --Filter using a lithium niobate substrate electrically connected to the output side of said -uner, d tuner is allowed to have a temoerature- whereby sa frequency characteristic and a temperature-frequency characteristic o' said surface acoustic -wave filter is canceled by the temperature-frequency characteristic of said tuner.
2. A video signal reproducing circuit according to claim 1, wherein said tuner is allowed to have the temperature-frecruency characteristic by a temperaturedecendent resonance circuit.
3. A video signal reproducing circuit according to claim 2, wherein said temperature-dependent resonance circuit utilizes a capacitor having a temperaturecapacitance characteristic.
4. A video signal reproducing circuit:. comprising at least:
18 j ' a tuner for receiving a broadcast signa-1 iherein and frequencyconverting the broadcast s-Jcn-a-.,- into an gnal; intermediate 'f:re=enc,,,, si a surface acous----c wave i':-i'-lter,.is- ing a i-iihiurn niobate substrate electrically connected to ---he c-,. itzutside ot: said tuner; and a video ecn-,a".-ze-- circuit connected to ---Eaceacoustic wave _he output side cj said su- via a detection integrated circult, whereby said tuner and said video ec-,a-"i-zer circuit are allowed to have te.-inr)e--ature---::rewu.ency character is tics res-Dectively and a zenr)erature-f--ecr-,ency said surface acoustic wave filter is cancelled '--v said z:emiDerature-f--ec-,-enc.v c.h.araczerist-cs.
-
5. A video signal reproducing circuit according zo claim 4, wherein said tuner is allowed to have a tempera rure -:E ency c--.aracter-'sc by a temperature dependent resonance circuit
6. JA video s-,ana-' reproducing circuit according to claim 5, wherein said temperature-dependent -resonance circuit utilizes a capacitor having a temperature capacitance characteristic.
7. A video signal reproducing circuit substantially as hereinbefore described, with reference to, and as illustrated by, the accompanying drawings.
- l.-
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04568997A JP3580975B2 (en) | 1997-02-28 | 1997-02-28 | Video signal reproduction circuit |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9802175D0 GB9802175D0 (en) | 1998-04-01 |
| GB2322747A true GB2322747A (en) | 1998-09-02 |
| GB2322747B GB2322747B (en) | 2001-04-25 |
Family
ID=12726363
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9802175A Expired - Fee Related GB2322747B (en) | 1997-02-28 | 1998-02-03 | Video signal reproducing circuit |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JP3580975B2 (en) |
| KR (1) | KR100258482B1 (en) |
| CN (1) | CN1123214C (en) |
| DE (1) | DE19808121C2 (en) |
| GB (1) | GB2322747B (en) |
| MY (1) | MY119629A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1037386A2 (en) * | 1999-03-18 | 2000-09-20 | Alps Electric Co., Ltd. | Television tuner with suppressed attenuation of level of video intermediate frequency with respect to rise in ambient temperature |
| US8953411B2 (en) | 2010-08-24 | 2015-02-10 | Snu R&Db Foundation | Apparatus and method for imaging a subsurface using frequency-domain elastic reverse-time migration |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3787612A (en) * | 1972-07-03 | 1974-01-22 | Zenith Radio Corp | Signal processing system for television receiver having acoustic surface wave devices for improved tuning and video demodulation |
| US5329319A (en) * | 1991-02-20 | 1994-07-12 | Zenith Electronics Corporation | Stabilized frequency and phase locked loop with saw devices on common substrate |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05191808A (en) * | 1992-01-13 | 1993-07-30 | Toshiba Corp | Satellite broadcasting receiver |
| TW353245B (en) * | 1995-06-06 | 1999-02-21 | Thomson Consumer Electronics | Saw filter for a tuner of a digital satellite receiver |
-
1997
- 1997-02-28 JP JP04568997A patent/JP3580975B2/en not_active Expired - Fee Related
-
1998
- 1998-02-03 GB GB9802175A patent/GB2322747B/en not_active Expired - Fee Related
- 1998-02-26 DE DE19808121A patent/DE19808121C2/en not_active Expired - Fee Related
- 1998-02-27 CN CN98100462A patent/CN1123214C/en not_active Expired - Fee Related
- 1998-02-27 MY MYPI98000876A patent/MY119629A/en unknown
- 1998-02-27 KR KR1019980006359A patent/KR100258482B1/en not_active IP Right Cessation
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3787612A (en) * | 1972-07-03 | 1974-01-22 | Zenith Radio Corp | Signal processing system for television receiver having acoustic surface wave devices for improved tuning and video demodulation |
| US5329319A (en) * | 1991-02-20 | 1994-07-12 | Zenith Electronics Corporation | Stabilized frequency and phase locked loop with saw devices on common substrate |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1037386A2 (en) * | 1999-03-18 | 2000-09-20 | Alps Electric Co., Ltd. | Television tuner with suppressed attenuation of level of video intermediate frequency with respect to rise in ambient temperature |
| EP1037386A3 (en) * | 1999-03-18 | 2003-08-13 | Alps Electric Co., Ltd. | Television tuner with suppressed attenuation of level of video intermediate frequency with respect to rise in ambient temperature |
| US8953411B2 (en) | 2010-08-24 | 2015-02-10 | Snu R&Db Foundation | Apparatus and method for imaging a subsurface using frequency-domain elastic reverse-time migration |
Also Published As
| Publication number | Publication date |
|---|---|
| KR100258482B1 (en) | 2000-06-15 |
| KR19980071791A (en) | 1998-10-26 |
| DE19808121A1 (en) | 1998-09-03 |
| JP3580975B2 (en) | 2004-10-27 |
| DE19808121C2 (en) | 2003-05-08 |
| CN1123214C (en) | 2003-10-01 |
| MY119629A (en) | 2005-06-30 |
| JPH10243306A (en) | 1998-09-11 |
| GB2322747B (en) | 2001-04-25 |
| GB9802175D0 (en) | 1998-04-01 |
| CN1194536A (en) | 1998-09-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20100203 |