JPH11274963A - Electronic tuner and rf modulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a mounting space, to enhance the latitude in design and to reduce its cost. SOLUTION: Local oscillation circuits 6, 12 output a local oscillating frequency signal based on channel data from a microcomputer at a set side. A frequency signal of the desired channel is extracted from a composite channel signal via band-pass filters 2, 7 and synthesized with the local oscillation frequency signal, and the result is outputted as an intermediate frequency signal via an intermediate frequency amplifier 11 and a band-pass filter 13. A crystal oscillator provided to the microcomputer at the side of the set is shared in common, and the local oscillation frequency signal is outputted based on the sole crystal oscillator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic tuner and an RF modulator used for a television receiver, a video tape recorder, and the like.

[0002]

2. Description of the Related Art A conventional electronic tuner, PLL (Phas
e Locked Loop) Tuning electronic tuner and PLL tuning RF
The (Radio Frequency) modulator will be described below.

FIG. 8 is a block diagram showing a configuration of a conventional PLL tuning electronic tuner. The upper half of FIG. 8 shows the configuration related to the UHF section (section for selecting channels in the UHF band), and the lower half shows the VUF section (VHF band and UHF band).
Section to select the low frequency band of the band)
Is shown.

In a conventional PLL tuning electronic tuner, an antenna (AN) is used when a UHF band channel is selected.
T IN), the composite channel signal input via
It passes through the UHF section. That is, the composite channel signal is sent to the band-pass filter 102, where the frequency signal of the desired channel is selectively extracted. The frequency signal of the desired channel is amplified by the high frequency amplifier 103 and sent to the mixer 105 via the band pass filter 104.

A high-frequency amplified signal from the band-pass filter 104 is input to the mixer 105, and a local oscillation frequency signal from the local oscillation circuit 106 is input thereto. It is converted into a frequency signal (IF signal). The intermediate frequency signal thus converted is amplified by an intermediate frequency amplifier 111, and then output as an intermediate frequency signal (IF signal) via a band-pass filter 113 to an output terminal (IF OU).
T). The local oscillation frequency signal is
The PLL is controlled by the PLL control IC 115 and output from the local oscillation circuit 106. The PLL control IC 115 is driven by a dedicated crystal oscillator 114.

On the other hand, in the conventional PLL tuning electronic tuner, a composite channel signal input via an antenna (ANT IN) is sent to a low-pass filter 101 when a VUF band channel is selected. Then, after the low frequency band components of the VHF band and the UHF band are extracted, they pass through the VUF section. That is, the composite channel signal is sent to the band pass filter 107,
Here, the frequency signal of the desired channel is selectively extracted. The frequency signal of the desired channel is amplified by the high frequency amplifier 108 and sent to the mixer 110 via the band pass filter 109.

A high-frequency amplified signal from the band-pass filter 109 is input to the mixer 110, and a local oscillation frequency signal from the local oscillation circuit 112 is input thereto. It is converted into a frequency signal (IF signal). The intermediate frequency signal thus converted is amplified by an intermediate frequency amplifier 111 and then output to an external terminal (IF signal) as an intermediate frequency signal (IF signal) via a band-pass filter 113.
OUT). The local oscillation frequency signal is PLL-controlled by the PLL control IC 115 and is output from the local oscillation circuit 112. The PLL control IC 115 is driven by a dedicated crystal oscillator 124.

The mixers 105 and 110, the local oscillators 106 and 112, and the intermediate frequency amplifier 1
Reference numeral 11 denotes an IC.

FIG. 9 is a block diagram showing a configuration example of a conventional PLL tuning RF modulator 126.

A composite channel signal input via an antenna (ANT IN) is sent to a high-frequency amplifier 121 via a high-pass filter 120, where it is amplified at a high frequency. The composite channel signal thus amplified in high frequency is sent to the mixer 122.

On the other hand, a video input terminal (VIDEO I
N) and the video and audio signals input via the audio input terminal (AUDIO IN)
In the L control modulator circuit 123, each signal is modulated. At this time, the modulated video signal and audio signal are combined (up-converted) with the local oscillation frequency signal, converted into a desired channel RF signal, and sent to the mixer 122 via the low-pass filter 125. Note that the local oscillation frequency signal is supplied to a PLL control IC similarly to the conventional PLL tuning electronic tuner.
(Not shown) to perform PLL control and output from a local oscillation circuit (not shown).
Further, the PLL control IC has a dedicated crystal oscillator 124.
Driven by

In the mixer 122, after the input two signals (a high-frequency amplified composite channel signal and an up-converted RF signal) are combined (not converted), the signal is output as a television signal to an output terminal (TV). O
UT).

In the above-mentioned PLL control modulator circuit 123, although not shown, when a video signal is input, the input level is controlled via a video clamp and a white clip, and then converted to an AM modulation signal by a video modulator. It is converted and sent to the mixer. On the other hand, the audio signal is FM-modulated and converted to a voice carrier frequency, and then sent to the mixer. In this mixer, the modulated video signal and audio signal and the local oscillation frequency signal are combined (up-converted) and sent to the low-pass filter 125 via a buffer amplifier as a desired channel frequency signal.

A conventional PLL tuning electronic tuner and a PLL
Each of the tuning RF modulators performs PLL control as shown in FIG. That is, according to the operation of the PLL control, for example, a reference clock of 4 MHz is sent from the local oscillation circuit (OSC) 132 to the 周 frequency divider 134. In the ４ frequency divider 134, the reference clock is frequency-divided by ４ and then input to a programmable frequency divider (divider) 133. Programmable frequency divider 13
In 3, the designated channel frequency is set based on the control data sent via the data interface 130. The output of the programmable frequency divider 133 is sent to the phase comparator 136.

On the other hand, the clock signal of the crystal oscillator 114 (or the crystal oscillator 124) is sent to the frequency divider 135 via the buffer 137. In the frequency divider (divider) 135, the clock signal is frequency-divided at a predetermined frequency division ratio based on the control data transmitted via the data interface 130, and then transmitted to the phase comparator 136.

The phase comparator 136 compares the phase of the output of the programmable frequency divider 133 with the phase of the output of the frequency divider 135 based on the control data sent via the data interface 130. You.

The result of the phase comparison by the phase comparator 136 is output as a control voltage control signal to the active filter 1.
The reference signal reflecting the comparison result is sent to the 発 振 frequency divider 134 from the local oscillation circuit 132 via the local oscillation circuit 132.

As described above, the local oscillation frequency is made to converge to the designated channel frequency.
The designated channel frequency is controlled based on control data (indicated by SDA in FIG. 10) sent from the set microcomputer via the data interface 130. In the figure, SCL represents a system clock. The set-side microcomputer is a one-chip microcomputer that controls a set power supply, a tuner channel, and controls various settings of a display screen.

[0019]

However, in the above-mentioned conventional technology, the PLL tuning electronic tuner and the PLL tuning RF modulator may be provided with dedicated crystal oscillators 114 and 124, respectively. Required, which hinders miniaturization.

Recently, a PLL tuning electronic tuner and a PL
There is a demand for further miniaturization of the L tuning RF modulator. Compact PLL tuning electronic tuner and PLL tuning RF
Conventionally, it has been necessary to use a small crystal oscillator to design a modulator. However, small crystal oscillators are not mainstream products in the market, so it is difficult to obtain them stably and at low cost.

On the other hand, if a mainstream product of the current size is adopted in the market, there is a problem that a great degree of freedom in design is sacrificed and an unreasonable pattern layout is forced.

An object of the present invention is to provide an electronic tuner and an RF modulator capable of reducing a mounting space, improving design flexibility, and reducing costs. It is in.

[0023]

According to a first aspect of the present invention, there is provided an electronic tuner including a PLL tuner for outputting a local oscillation frequency signal based on channel data from a set microcomputer. An electronic tuner that includes a frequency signal of a desired channel extracted from a composite channel signal and the local oscillation frequency signal and outputs the resultant signal as an intermediate frequency signal has the following features.

That is, in the electronic tuner, a single crystal oscillator is shared between the PLL tuning unit and the set-side microcomputer, and the local oscillation frequency signal is output based on the crystal oscillator. It is characterized by.

According to the above invention, the local oscillation frequency signal is output by the PLL tuning unit based on the channel data from the set microcomputer. This local oscillation frequency signal is synthesized with the frequency signal of the desired channel extracted from the composite channel signal and output as an intermediate frequency signal.

According to the electronic tuner of the present invention,
A single crystal oscillator is shared between the PLL tuning unit and the microcomputer on the set side, and the local oscillation frequency signal is output based on the crystal oscillator. In addition, it is possible to avoid using a small crystal oscillator that is conventionally required and is not a mainstream product in the market. In addition, by adopting a mainstream product of the current size in the market, it is possible to surely avoid a problem that an unreasonable pattern layout is forced at the expense of design flexibility. Therefore, according to the electronic tuner, it is possible to reliably provide an electronic tuner capable of reducing a mounting space, improving design flexibility, and reducing costs.

According to a second aspect of the present invention, there is provided an RF modulator which modulates a local oscillation frequency signal, a video signal and an audio signal generated based on channel data from a set microcomputer. The following measures were taken in an RF modulator comprising a PLL tuning unit for combining the RF signal of the desired channel and converting it into an RF signal of a desired channel, and combining the converted RF signal and a composite channel signal and outputting as an output signal. It is characterized by.

That is, the RF modulator is provided with the PL
A single crystal oscillator is shared between the L tuning unit and the set-side microcomputer, and the local oscillation frequency signal is output based on the crystal oscillator.

According to the above invention, the local oscillation frequency signal is generated based on channel data from the set microcomputer. This local oscillation frequency signal is combined with a signal obtained by modulating a video signal and an audio signal by a PLL tuning unit, and is converted into an RF signal of a desired channel. R converted in this way
The F signal is combined with the composite channel signal and output as an output signal of the RF modulator.

According to the RF modulator of the present invention, only one crystal oscillator is shared between the PLL tuning unit and the set-side microcomputer, and the local oscillation frequency signal is generated based on the crystal oscillator. Because of the output, it is possible to avoid using a small crystal oscillator that is conventionally required and is not a mainstream product in the market for designing a small RF modulator. In addition, by adopting a mainstream product of the current size in the market, it is possible to surely avoid a problem that an unreasonable pattern layout is forced at the expense of design flexibility. Therefore, according to the RF modulator, it is possible to reliably provide an RF modulator capable of reducing a mounting space, improving design flexibility, and reducing costs.

According to a third aspect of the present invention, there is provided an electronic tuner for synthesizing a frequency signal of a desired channel extracted from a composite channel signal and a first local oscillation frequency signal as an intermediate frequency signal. The PLL tuning electronic tuner to be output and the PLL tuning electronic tuner provided integrally with the PLL tuning electronic tuner are combined with a signal obtained by modulating a video signal and an audio signal and converted into an RF signal of a desired channel. The RF modulator that combines the RF signal and the composite channel signal and outputs the combined signal as an output signal, and the first and second local oscillation frequency signals are generated based on channel data from the microcomputer on the set side. And the PLL tuning electronic tuner, the RF modulator, and the set-side Black is the only crystal oscillator with the computer is characterized in that it is shared.

According to the above invention, the PLL tuning electronic tuner and the RF modulator are provided integrally.
In the PLL tuning electronic tuner, the frequency signal of the desired channel extracted from the composite channel signal and the first local oscillation frequency signal are combined and output as an intermediate frequency signal. In the RF modulator, the second local oscillation frequency signal and a signal obtained by modulating the video signal and the audio signal are combined and converted into an RF signal of a desired channel. The RF signal and the composite channel signal thus converted are combined and output as an output signal of the RF modulator.

The first and second local oscillation frequency signals are generated based on channel data from a set microcomputer, and are connected to the PLL tuning electronic tuner, the RF modulator, and the set microcomputer. Since only one crystal oscillator is shared between the two, there is no need to provide a crystal oscillator separately from the set-side microcomputer on the PLL tuning electronic tuner side and the RF modulator side as in the related art. . Therefore, it is ensured that a large sacrifice in design freedom and an unreasonable pattern layout due to the provision of a mainstream product of the current size in the market separately on the PLL tuning electronic tuner side as in the past can be forced. Can be avoided. Therefore, reduction of mounting space,
An electronic tuner capable of improving design flexibility and reducing costs can be provided.

According to a fourth aspect of the present invention, there is provided an electronic tuner for synthesizing a frequency signal of a desired channel extracted from a composite channel signal and a first local oscillation frequency signal as an intermediate frequency signal. The PLL tuning electronic tuner to be output and the PLL tuning electronic tuner provided integrally with the PLL tuning electronic tuner are combined with a signal obtained by modulating a video signal and an audio signal and converted into an RF signal of a desired channel. The RF modulator that combines the RF signal and the composite channel signal and outputs the combined signal as an output signal, and the first and second local oscillation frequency signals are generated based on channel data from the microcomputer on the set side. And the only one between the RF modulator and the set-side microcomputer. Crystal oscillator is characterized in that it is shared.

According to the above invention, the PLL tuning electronic tuner and the RF modulator are provided integrally.
In the PLL tuning electronic tuner, the frequency signal of the desired channel extracted from the composite channel signal and the first local oscillation frequency signal are combined and output as an intermediate frequency signal. In the RF modulator, the second local oscillation frequency signal and a signal obtained by modulating the video signal and the audio signal are combined and converted into an RF signal of a desired channel. The RF signal and the composite channel signal thus converted are combined and output as an output signal of the RF modulator.

The first and second local oscillation frequency signals are generated based on channel data from a set microcomputer, and are the only crystal oscillators between the RF modulator and the set microcomputer. Is shared, so that the RF
In the modulator, it is not necessary to provide a crystal oscillator separately from the set microcomputer. Therefore, it is ensured that a large sacrifice in design freedom and an unreasonable pattern layout due to the provision of a mainstream product of the current size in the market separately on the PLL tuning electronic tuner side as in the past can be forced. Can be avoided.
Therefore, it is possible to provide a PLL tuning electronic tuner capable of reducing a mounting space, improving design flexibility, and reducing costs.

According to a fifth aspect of the present invention, there is provided an electronic tuner for synthesizing a frequency signal of a desired channel extracted from a composite channel signal and a first local oscillation frequency signal as an intermediate frequency signal. The PLL tuning electronic tuner to be output and the PLL tuning electronic tuner provided integrally with the PLL tuning electronic tuner are combined with a signal obtained by modulating a video signal and an audio signal and converted into an RF signal of a desired channel. The RF modulator that combines the RF signal and the composite channel signal and outputs the combined signal as an output signal, and the first and second local oscillation frequency signals are generated based on channel data from the microcomputer on the set side. At the same time, between the PLL tuning electronic tuner and the set-side microcomputer It is characterized in that one crystal oscillator is shared.

According to the above invention, the PLL tuning electronic tuner and the RF modulator are provided integrally.
In the PLL tuning electronic tuner, the frequency signal of the desired channel extracted from the composite channel signal and the first local oscillation frequency signal are combined and output as an intermediate frequency signal. In the RF modulator, the second local oscillation frequency signal and a signal obtained by modulating the video signal and the audio signal are combined and converted into an RF signal of a desired channel. The RF signal and the composite channel signal thus converted are combined and output as an output signal of the RF modulator.

The first and second local oscillation frequency signals are generated based on channel data from a set-side microcomputer, and are the only crystals between the PLL tuning electronic tuner and the set-side microcomputer. Since the oscillator is shared, as before,
In the PLL tuning electronic tuner, it is not necessary to provide a crystal oscillator separately from the set-side microcomputer. Therefore, it is ensured that a large sacrifice in design freedom and an unreasonable pattern layout due to the provision of a mainstream product of the current size in the market separately on the PLL tuning electronic tuner side as in the past can be forced. Can be avoided. Therefore, it is possible to provide a PLL tuning electronic tuner capable of reducing a mounting space, improving design flexibility, and reducing costs.

[0040]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

PLL Tuning Electronic Tuner 1 of the Present Embodiment
6 has a configuration as shown in FIG. The upper half of FIG. 1 shows the configuration related to the UHF section (section for selecting channels in the UHF band), and the lower half shows the configuration related to the VUF section (section for selecting channels in the low-frequency band of the VHF and UHF bands). Is shown.

PLL Tuning Electronic Tuner 1 of this Embodiment
In 6, at the time of channel selection in the UHF band, the composite channel signal input via the antenna (ANT IN) passes through the UHF section. That is, the composite channel signal is sent to the band-pass filter 2, and the frequency signal of the desired channel is selectively extracted. The frequency signal of the desired channel is amplified by the high-frequency amplifier 3 and sent to the mixer (mixer) 5 via the band-pass filter 4.

The mixer 5 includes a band-pass filter 4
, And a local oscillation frequency signal from the local oscillation circuit 6, where they are combined (down-converted) and converted into an intermediate frequency signal (IF signal). The intermediate frequency signal thus converted is amplified by the intermediate frequency amplifier 11 and then output from the output terminal (IF OUT) via the band-pass filter 13 as an intermediate frequency signal.

On the other hand, in the PLL tuning electronic tuner 16 according to the present embodiment, the composite channel signal input via the antenna (ANT IN) is sent to the low-pass filter 1 when the VUF band channel is selected. Here, after the low frequency band components of the VHF band and the UHF band are extracted, they pass through the VUF section. That is, the composite channel signal is sent to the bandpass filter 7, where the frequency signal of the desired channel is selectively extracted. The frequency signal of the desired channel is amplified by the high frequency amplifier 8 and sent to the mixer 10 via the band pass filter 9.

The mixer 10 receives the high-frequency amplified signal from the band-pass filter 9 and the local oscillation frequency signal from the local oscillation circuit 12, where the signal is synthesized (down-converted) and converted into an intermediate frequency signal. Is converted to The intermediate frequency signal thus converted is amplified by the intermediate frequency amplifier 11, and then output to the outside as an intermediate frequency signal from the output terminal (IF OUT) via the band pass filter 13.

The mixers 5 and 10, the local oscillation circuits 6 and 12, and the intermediate frequency amplifier 11 are integrated into an IC.

The local oscillation frequency signal is PLL-controlled by the PLL control IC 15 and output from the local oscillation circuit 6. In addition, the PLL
The control IC 15 is not driven by a dedicated crystal oscillator but driven by a crystal oscillator of a set-side microcomputer (microcomputer) not shown. In other words, according to the present embodiment, the PLL tuning electronic tuner 1
One crystal oscillator is shared between the set 6 and the set-side microcomputer. The set-side microcomputer is a one-chip microcomputer that controls a set power supply, a tuner channel, and controls various settings of a display screen. The PLL control IC 15 receives control data such as reception channel data from a set-side microcomputer via a 3-wire or 12C bus (both not shown).

In the set microcomputer, the clock from the crystal oscillator is an operation reference signal used for data transfer inside the microcomputer every clock as an operation clock. On the other hand, the PLL tuning electronic tuner 16
In this case, the local oscillation frequency is used as a reference signal of a frequency for converging to a designated channel.

As described above, it is unnecessary to provide a crystal oscillator separately from the set-side microcomputer on the PLL tuning electronic tuner side as in the related art. Therefore, it is ensured that a large sacrifice in design freedom and an unreasonable pattern layout due to the provision of a mainstream product of the current size in the market separately on the PLL tuning electronic tuner side as in the past can be forced. Can be avoided. Therefore, it is possible to provide a PLL tuning electronic tuner capable of reducing a mounting space, improving design flexibility, and reducing costs.

FIG. 2 shows PLL tuning R according to this embodiment.
FIG. 3 is a block diagram illustrating a configuration example of an F modulator 26.

The composite channel signal input via the antenna (ANT IN) is sent to the high-frequency amplifier 21 via the high-pass filter 20, where it is subjected to high-frequency amplification. The composite channel signal thus amplified in high frequency is sent to a mixer (mixer) 22.

On the other hand, a video input terminal (VIDEO I
N) and the video and audio signals input via the audio input terminal (AUDIO IN)
In the L control modulator circuit 23, each signal is modulated. At this time, the modulated video signal and audio signal are combined (up-converted) with the local oscillation frequency signal, converted into a desired channel RF signal, and sent to the mixer 22 via the low-pass filter 25.

The local oscillation frequency signal is PLL-controlled by a PLL control IC (not shown) and output from a local oscillation circuit (not shown), as in the case of the PLL tuning electronic tuner 16 according to the present embodiment. Is done. Further, the PLL control IC is not driven by a dedicated crystal oscillator but driven by a crystal oscillator of a set-side microcomputer (not shown).
In other words, according to the present embodiment, one crystal oscillator is shared between the PLL tuning RF modulator 26 and the set-side microcomputer.

Therefore, as in the prior art, the PLL tuning RF
On the modulator side, there is no need to provide a crystal oscillator separately from the set microcomputer. Therefore, it is ensured that a large sacrifice in design freedom and an unreasonable pattern layout can be imposed due to the fact that a current size mainstream product in the market is separately provided on the PLL tuning RF modulator side as in the past. Can be avoided. Therefore, it is possible to provide a PLL tuning RF modulator that can reduce the mounting space, improve the design flexibility, and reduce the cost.

In the mixer 22, the input two signals (a high-frequency amplified composite channel signal and an up-converted RF signal) are combined (not converted) and then output as a television signal at an output terminal (TV). OU
T).

In the PLL control modulator circuit 23, although not shown, when a video signal is input, the input level is controlled via a video clamp and a white clip, and then converted to an AM modulation signal by a video modulator. It is converted and sent to the mixer. On the other hand, the audio signal is FM-modulated and converted to a voice carrier frequency, and then sent to the mixer. In this mixer, the modulated video signal and audio signal and the local oscillation frequency signal are combined (up-converted) and sent to the low-pass filter 25 via a buffer amplifier as a frequency signal of a desired channel.

Both the PLL tuning electronic tuner 16 and the PLL tuning RF modulator 26 according to the present embodiment perform the PLL control as shown in FIG.
That is, according to the operation of the PLL control, for example, the reference clock of 4 MHz is 1/1 from the local oscillation circuit (OSC) 32.
The signal is sent to the 分 frequency divider 34. In the 分 frequency divider 34, the reference clock is frequency-divided by １ ／ and then input to a programmable frequency divider (divider) 33. In the programmable frequency divider 33, the designated channel frequency is set based on the control data sent via the data interface 30. The output of the programmable frequency divider 33 is
The signal is sent to the phase comparator 36.

On the other hand, the reference signal (reference signal) of the crystal oscillator of the microcomputer on the set side is
7 to a frequency divider (divider) 35. In the frequency divider 35, the reference signal is frequency-divided at a predetermined frequency division ratio based on the control data transmitted via the data interface 30, and then transmitted to the phase comparator 36.

In the phase comparator 36, based on the control data sent via the data interface 30, the phase of the output of the programmable frequency divider 33 and
The phase of the output of the frequency divider 35 is compared.

The result of the phase comparison by the phase comparator 36 is used as a control voltage control signal as the active filter 31.
The reference signal on which the comparison result is reflected is sent to the 1/4 frequency divider 34 from the local oscillation circuit 32 via the local oscillation circuit 32.

As described above, the local oscillation frequency (Fout) is made to converge on the designated channel frequency. The designated channel frequency is controlled based on control data (indicated by SDA in FIG. 3) sent from the set microcomputer via the data interface 30. In the figure, SCL represents a system clock.

Here, the PLL tuning electronic tuner 16 and P
An example in which the present invention is applied to a so-called two-in-one (two-in-one) type tuner in which the LL tuning RF modulator 26 is integrated will be described below with reference to FIG.

A 2 in 1 type tuner 50 shown in FIG.
Is a PLL tuning electronic tuner 16 having the above configuration.
And the PLL tuning RF modulator 26 are integrally formed, and the PLL control IC 15 of the PLL tuning electronic tuner 16 is driven by the crystal oscillator of the set-side microcomputer. I have.

According to the above configuration, in the 2-in-1 type tuner 50, one crystal oscillator (the crystal oscillator of the set microcomputer) is shared between the PLL tuning electronic tuner 16 and the set microcomputer. Have been.

For this reason, it is not necessary to provide a crystal oscillator separately from the set-side microcomputer on the PLL tuning electronic tuner 16 side as in the related art. Therefore, it is ensured that a large sacrifice in design freedom and an unreasonable pattern layout due to the provision of a mainstream product of the current size in the market separately on the PLL tuning electronic tuner side as in the past can be forced. Can be avoided. Therefore, it is possible to provide a 2-in-1 type tuner 50 capable of reducing a mounting space, improving design flexibility, and reducing costs.

Here, the PLL tuning electronic tuner 16 and P
LL tuning RF modulator 26 and integrated 2in
Another example in which the present invention is applied to a one (two in one) type tuner will be described below with reference to FIG.

A 2-in-1 type tuner 51 shown in FIG.
Is a PLL tuning electronic tuner 16 having the above configuration.
And the PLL tuning RF modulator 26 are integrally formed, and the PLL tuning RF modulator 26
The PLL control IC in the PLL control modulator circuit 23 is driven by the crystal oscillator of the set-side microcomputer.

According to the above configuration, one crystal oscillator (the crystal oscillator of the set microcomputer) is shared between the PLL tuning RF modulator 26 and the set microcomputer.

Therefore, as in the prior art, the PLL tuning RF
On the modulator 26 side, it is not necessary to provide a crystal oscillator separately from the set-side microcomputer. Therefore, it is ensured that a large sacrifice in design freedom and an unreasonable pattern layout due to the provision of a mainstream product of the current size in the market separately on the PLL tuning electronic tuner side as in the past can be forced. Can be avoided. Therefore, it is possible to provide a 2-in-1 type tuner 51 that can reduce the mounting space, improve the design flexibility, and reduce the cost.

Here, the PLL tuning electronic tuner 16 and P
2in integrated with LL tuning RF modulator 26
Still another example in which the present invention is applied to a one (two in one) type tuner will be described below with reference to FIG.

A 2-in-1 type tuner 52 shown in FIG.
Is a PLL tuning electronic tuner 16 having the above configuration.
And the PLL tuning RF modulator 26 are integrally formed. The PLL control IC 15 of the PLL tuning electronic tuner 16 and the P control in the PLL control modulator circuit 23 of the PLL tuning RF modulator 26 are integrated.
The LL control IC is driven by a crystal oscillator of the set-side microcomputer.

According to the above configuration, one crystal oscillator (the crystal oscillator of the set microcomputer) is shared between the PLL tuning electronic tuner 16, the PLL tuning RF modulator 26, and the set microcomputer. Have been.

Therefore, as in the prior art, the PLL tuning electronic tuner 16 and the PLL tuning RF modulator 26
On the side, it is not necessary to provide a crystal oscillator separately from the set-side microcomputer. Therefore, it is ensured that a large sacrifice in design freedom and an unreasonable pattern layout due to the provision of a mainstream product of the current size in the market separately on the PLL tuning electronic tuner side as in the past can be forced. Can be avoided. Therefore, it is possible to provide a 2-in-1 type tuner 52 capable of reducing the mounting space, improving the design flexibility, and reducing the cost as compared with the examples shown in FIGS. 4 and 5.

In the example shown in FIG. 6, the PLL control IC 15 of the PLL tuning electronic tuner 16 and the PLL control IC in the PLL control modulator circuit 23 of the PLL tuning RF modulator 26 are connected to the set side. Each of them is driven by a crystal oscillator of a microcomputer. At this time, the PLL tuning electronic tuner 1 is used.
6 and the PLL tuning RF modulator 26 need to be separately connected to the crystal oscillator of the set-side microcomputer.

However, according to the 2-in-1 type tuner 53 shown in FIG. 7, the PLL tuning electronic tuner 16 is connected to the terminal OSC1 connected to the PLL control IC 15.
And the PLL tuning RF modulator 26
Has a terminal OSC2 connected to the PLL control IC in the PLL control modulator circuit 23, so that the terminals OSC1 and OSC2 are connected, and one of these terminals is connected to the crystal oscillator of the set-side microcomputer. With the connection, the same operation and effect as in the example of FIG. 5 can be obtained.

As described above, in the example of FIG. 7, the interconnection with the microcomputer on the set side can be simplified as compared with the example of FIG. 6, and the terminals OSC1 and OSC2 connect the clock signals to other circuits, respectively. It can be used as a relay terminal to output to.

[0077]

According to the electronic tuner of the first aspect of the present invention,
As described above, a unique crystal oscillator is shared between the PLL tuning unit and the set-side microcomputer, and a local oscillation frequency signal is output based on the crystal oscillator.

Therefore, a single crystal oscillator is shared between the PLL tuning unit and the set microcomputer, and the local oscillation frequency signal is output based on the crystal oscillator. In order to design the tuner, it is possible to avoid using a small crystal oscillator which is conventionally required and is not a mainstream product in the market. In addition, by adopting a mainstream product of the current size in the market, it is possible to surely avoid a problem that an unreasonable pattern layout is forced at the expense of design flexibility. Therefore, according to the above-mentioned electronic tuner, there is an effect that an electronic tuner that can reduce the mounting space, improve the degree of freedom in design, and reduce the cost can be reliably provided.

In the RF modulator according to the second aspect of the present invention, as described above, only one crystal oscillator is shared between the PLL tuning unit and the set-side microcomputer, and the local oscillation frequency is determined based on the crystal oscillator. A signal is output.

Therefore, a single crystal oscillator is shared between the PLL tuning unit and the set-side microcomputer, and the local oscillation frequency signal is output based on the crystal oscillator. In order to design the modulator, it is possible to avoid using a small crystal oscillator that is conventionally required and is not mainstream in the market. In addition, by adopting a mainstream product of the current size in the market, it is possible to surely avoid a problem that an unreasonable pattern layout is forced at the expense of design flexibility. Therefore, according to the above-mentioned RF modulator, it is possible to reliably provide an RF modulator capable of reducing a mounting space, improving design flexibility, and reducing costs.

As described above, the electronic tuner according to the third aspect of the invention combines the frequency signal of the desired channel extracted from the composite channel signal with the first local oscillation frequency signal and outputs the combined signal as an intermediate frequency signal. A tuning electronic tuner, which is provided integrally with the PLL tuning electronic tuner, synthesizes a second local oscillation frequency signal and a signal obtained by modulating a video signal and an audio signal, and converts the synthesized signal into an RF signal of a desired channel; An RF modulator that combines the RF signal and the composite channel signal and outputs the combined signal as an output signal; and the first and second local oscillation frequency signals are generated based on channel data from a set-side microcomputer. PLL tuning electronic tuner, the RF modulator, and the set-side microcomputer The only crystal oscillator with the over motor is characterized in that it is shared.

Therefore, the first and second local oscillation frequency signals are generated based on channel data from the set microcomputer, and the PLL
Since only one crystal oscillator is shared between the tuning electronic tuner, the RF modulator, and the set microcomputer, the PLL tuning electronic tuner and the RF modulator are different from the set tuning as in the related art. It is not necessary to provide a crystal oscillator separately from the microcomputer. Therefore, it is ensured that a large sacrifice in design freedom and an unreasonable pattern layout due to the provision of a mainstream product of the current size in the market separately on the PLL tuning electronic tuner side as in the past can be forced. Can be avoided. Therefore, it is possible to provide an electronic tuner that can reduce the mounting space, improve the design flexibility, and reduce the cost.

As described above, the electronic tuner of the invention according to claim 4 synthesizes the frequency signal of the desired channel extracted from the composite channel signal and the first local oscillation frequency signal and outputs it as an intermediate frequency signal. A tuning electronic tuner, which is provided integrally with the PLL tuning electronic tuner, synthesizes a second local oscillation frequency signal and a signal obtained by modulating a video signal and an audio signal, and converts the synthesized signal into an RF signal of a desired channel; An RF modulator that combines the RF signal and the composite channel signal and outputs the combined signal as an output signal; and the first and second local oscillation frequency signals are generated based on channel data from a set-side microcomputer. The only crystal oscillator between the RF modulator and the set-side microcomputer is It is characterized in that it is closed.

Therefore, the first and second local oscillation frequency signals are generated based on the channel data from the set microcomputer, and only one signal is provided between the RF modulator and the set microcomputer. Since the crystal oscillator is shared, it is not necessary to provide a crystal oscillator separately from the set-side microcomputer in the RF modulator as in the related art. Therefore, it is ensured that a large sacrifice in design freedom and an unreasonable pattern layout due to the provision of a mainstream product of the current size in the market separately on the PLL tuning electronic tuner side as in the past can be forced. Can be avoided. Therefore, it is possible to provide a PLL tuning electronic tuner capable of reducing a mounting space, improving design flexibility, and reducing costs.

According to a fifth aspect of the present invention, there is provided a PLL for synthesizing a frequency signal of a desired channel extracted from a composite channel signal and a first local oscillation frequency signal, and outputting as an intermediate frequency signal. A tuning electronic tuner, which is provided integrally with the PLL tuning electronic tuner, synthesizes a second local oscillation frequency signal and a signal obtained by modulating a video signal and an audio signal, and converts the synthesized signal into an RF signal of a desired channel; An RF modulator that combines the RF signal and the composite channel signal and outputs the combined signal as an output signal; and the first and second local oscillation frequency signals are generated based on channel data from a set-side microcomputer. The only crystal oscillator between the PLL tuning electronic tuner and the microcomputer on the set side Child is characterized by being shared.

Therefore, the first and second local oscillation frequency signals are generated based on the channel data from the microcomputer on the set side, and the PLL
Since the only crystal oscillator is shared between the tuning electronic tuner and the set-side microcomputer, as in the related art, in the PLL tuning electronic tuner, the crystal oscillator is provided separately from the set-side microcomputer. It is not necessary to provide. Therefore, it is ensured that a large sacrifice in design freedom and an unreasonable pattern layout due to the provision of a mainstream product of the current size in the market separately on the PLL tuning electronic tuner side as in the past can be forced. Can be avoided. Therefore, reduction of mounting space,
There is an effect that it is possible to provide a PLL tuning electronic tuner that can improve the design flexibility and reduce the cost.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a PLL tuning electronic tuner according to the present invention.

FIG. 2 is a block diagram showing a configuration example of a PLL tuning RF modulator according to the present embodiment.

FIG. 3 is a diagram illustrating PLLs performed in the PLL tuning electronic tuner and the PLL tuning RF modulator, respectively.
It is a block diagram which shows control.

FIG. 4 is an explanatory diagram showing an example in which the present invention is applied to a so-called 2-in-1 type tuner in which a PLL tuning electronic tuner and a PLL tuning RF modulator are integrated.

FIG. 5 is an explanatory diagram showing another example in which the present invention is applied to a 2-in-1 type tuner in which a PLL tuning electronic tuner and a PLL tuning RF modulator are integrated.

FIG. 6 is an explanatory diagram showing still another example in which the present invention is applied to a 2-in-1 type tuner in which a PLL tuning electronic tuner and a PLL tuning RF modulator are integrated.

FIG. 7 is an explanatory diagram showing still another example in which the present invention is applied to a 2-in-1 type tuner in which a PLL tuning electronic tuner and a PLL tuning RF modulator are integrated.

FIG. 8 is a block diagram illustrating a configuration example of a conventional PLL tuning electronic tuner.

FIG. 9 is a block diagram showing a configuration example of a conventional PLL tuning RF modulator.

FIG. 10 is a block diagram showing PLL control performed in the conventional PLL tuning electronic tuner and the conventional PLL tuning RF modulator, respectively.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Low pass filter 2 Band pass filter 3 High frequency amplifier 4 Band pass filter 5 Mixer 6 Local oscillation circuit 7 Band pass filter 8 High frequency amplifier 9 Band pass filter 10 Mixer 11 Intermediate frequency amplifier 12 Local oscillation circuit 13 Band pass filter 16 PLL selection Station electronic tuner 22 Mixer 23 PLL control modulator circuit 26 PLL tuning RF modulator

Claims (5)

[Claims] 1. A PLL tuning unit for outputting a local oscillation frequency signal based on channel data from a set-side microcomputer, wherein a frequency signal of a desired channel extracted from a composite channel signal is combined with the local oscillation frequency signal. An electronic tuner that outputs an intermediate frequency signal, wherein only one crystal oscillator is shared between the PLL tuning unit and the set-side microcomputer, and the local oscillation frequency signal is generated based on the crystal oscillator. An electronic tuner characterized by being output. 2. A PL for synthesizing a local oscillation frequency signal generated based on channel data from a set-side microcomputer with a signal obtained by modulating a video signal and an audio signal, and converting the signal into an RF signal of a desired channel.
An RF modulator comprising an L tuning unit, combining the converted RF signal and the composite channel signal and outputting the combined signal as an output signal, wherein only a crystal oscillator is provided between the PLL tuning unit and the set-side microcomputer. Wherein the local oscillation frequency signal is output based on the crystal oscillator. 3. A PLL tuning electronic tuner that combines a frequency signal of a desired channel extracted from a composite channel signal and a first local oscillation frequency signal and outputs an intermediate frequency signal, and the PLL tuning electronic tuner integrated with the PLL tuning electronic tuner. , The second
An RF modulator that combines a local oscillation frequency signal with a signal obtained by modulating a video signal and an audio signal, converts the signal into an RF signal of a desired channel, combines the RF signal with a composite channel signal, and outputs the combined signal as an output signal; The first and second local oscillation frequency signals are generated based on channel data from the microcomputer on the set side, and the PLL tuning electronic tuner, the RF modulator,
And an electronic tuner wherein a single crystal oscillator is shared with the set-side microcomputer. 4. A PLL tuning electronic tuner for synthesizing a frequency signal of a desired channel extracted from a composite channel signal and a first local oscillation frequency signal and outputting as an intermediate frequency signal; , The second
An RF modulator that combines a local oscillation frequency signal with a signal obtained by modulating a video signal and an audio signal, converts the signal into an RF signal of a desired channel, combines the RF signal with a composite channel signal, and outputs the combined signal as an output signal; The first and second local oscillation frequency signals are generated based on channel data from a set-side microcomputer, and a single crystal oscillator is shared between the RF modulator and the set-side microcomputer. An electronic tuner characterized in that: 5. A PLL tuning electronic tuner that combines a frequency signal of a desired channel extracted from a composite channel signal and a first local oscillation frequency signal and outputs an intermediate frequency signal, and a PLL tuning electronic tuner integrated with the PLL tuning electronic tuner. , The second
An RF modulator that combines a local oscillation frequency signal with a signal obtained by modulating a video signal and an audio signal, converts the signal into an RF signal of a desired channel, combines the RF signal with a composite channel signal, and outputs the combined signal as an output signal; The first and second local oscillation frequency signals are generated based on channel data from the set-side microcomputer, and the only crystal oscillator between the PLL tuning electronic tuner and the set-side microcomputer is An electronic tuner characterized by being shared.