TV signal receiving tuner capable of outputting oscillation signal having wide frequency band by means of single local oscillator

A TV signal receiving tuner which is small in size and inexpensive due to a reduced number of local oscillators. In the TV signal receiving tuner, a local oscillation signal output from a local oscillator is directly applied to a first mixer through a first programmable divider to receive a UHF TV signal, the local oscillation signal output from the local oscillator is applied to the first mixer after its frequency is divided to 1/3 by the first programmable divider to receive a VHF high-band TV signal, and the local oscillation signal output from the local oscillator is applied to the first mixer after its frequency is divided to 1/5 by the first programmable divider to receive a VHF low-band TV signal.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a TV signal receiving tuner and, more specifically, to a TV signal receiving tuner which can be reduced in size and cost.

2. Description of the Related Art

TV signals are divided into UHF (806 to 470 MHz in the U.S.), VHF high-band (216 to 174 MHz in the U.S.) and VHF low-band (88 to 54 MHz in the U.S.) signals when they are received.

As shown inFIG. 3, a tuner comprises an input terminal32connected to an antenna31, a UHF mono-tuning circuit33, a UHF high-frequency amplifier34, a UHF multi-tuning circuit35, a UHF mixer36, a UHF local oscillator37, a UHF resonance circuit38, a VHF high-band mono-tuning circuit39, a VHF high-band high-frequency amplifier40, a VHF high-band multi-tuning circuit41, a VHF high-band mixer42, a VHF high-band local oscillator43, a VHF high-band resonance circuit44, a VHF low-band mono-tuning circuit45, a VHF low-band high-frequency amplifier46, a VHF low-band multi-tuning circuit47, a VHF low-band mixer48, a VHF low-band local oscillator49, a VHF low-band resonance circuit50, a filter51, an intermediate-frequency amplifier52, a PLL IC53, a quartz oscillator54, a local oscillator switch55and a tuner output terminal56.

To receive a UHF TV signal, a TV signal received by the antenna31is tuned by the UHF mono-tuning circuit33, amplified by the UHF high-frequency amplifier34, and tuned by the UHF multi-tuning circuit35. The tuning frequencies of the UHF mono-tuning circuit33and the UHF multi-tuning circuit35are changed by a tuning voltage Vt output from the PLL IC53and tuned at the frequency band of a channel to be received. Since the output impedance of the antenna31is low and the input impedances of the UHF high-frequency amplifier34and the UHF multi-tuning circuit35are high, impedance matching is carried out by the UHF mono-tuning circuit33.

The TV signal output from the UHF multi-tuning circuit35is applied to the UHF mixer36. One input terminal of the UHF mixer36is connected to the output terminal of the UHF multi-tuning circuit35and the other input terminal is connected to the UHF local oscillator37. The UHF local oscillator37is connected to the UHF resonance circuit38so that a local oscillation signal output from the UHF local oscillator37is changed by the tuning voltage Vt input from the PLL IC53into the UHF resonance circuit38. Since the UHF local oscillator37outputs a local oscillation signal which is 44 MHz higher than a TV signal to be received, a converted signal having an intermediate frequency of 44 MHz is output from the output terminal of the UHF mixer36.

The intermediate-frequency signal is applied to the filter51. The filter51is a band-pass filter having sharp characteristics and connected to the intermediate-frequency amplifier52. The intermediate-frequency signal amplified by the intermediate-frequency amplifier52is output from the output terminal56of the tuner.

When a VHF high-band TV signal is received, the TV signal received by the antenna31is applied to the filter51through the VHF high-band mono-tuning circuit39, VHF high-band high-frequency amplifier40, VHF high-band multi-tuning circuit41and VHF high-band mixer42. As the operations of the above circuits are the same as the UHF circuits, their descriptions are omitted. As the operation of the VHF high-band local oscillator43and the operation of the VHF high-band resonance circuit44are also the same as the UHF circuits, their descriptions are omitted.

When a VHF low-band TV signal is received, the TV signal received by the antenna31is applied to the filter51through the VHF low-band mono-tuning circuit45, VHF low-band high-frequency amplifier46, VHF low-band multi-tuning circuit47and VHF low-band mixer48. As the operations of the above circuits are the same as the UHF circuits, their descriptions are omitted. As the operation of the VHF low-band local oscillator49and the operation of the VHF low-band resonance circuit50are also the same as the UHF circuits, their descriptions are omitted.

The PLL IC53is a circuit for selecting a channel to be received. To receive a UHF band channel, a UHF band switch voltage Vu for selecting a UHF band channel is applied to the UHF high-frequency amplifier34and a tuning voltage Vt corresponding to the selected channel is applied to the UHF mono-tuning circuit33, the UHF multi-tuning circuit35and the UHF resonance circuit38. To receive a VHF high-band channel, a VHF high-band switch voltage Vhi for selecting a VHF high-band channel is applied to the VHF high-band high-frequency amplifier40and a tuning voltage Vt corresponding to the selected channel is applied to the VHF high-band mono-tuning circuit39, the VHF high-band multi-tuning circuit41and the VHF high-band resonance circuit44. To receive a VHF low-band channel, a VHF low-band switch voltage Vhi for selecting a VHF low-band channel is applied to the VHF low-band high-frequency amplifier46and a tuning voltage Vt corresponding to the selected channel is applied to the VHF low-band mono-tuning circuit45, the VHF low-band multi-tuning circuit47and the VHF low-band resonance circuit50. Further, a control voltage is applied to a local oscillator switch55in the PLL IC53.

SUMMARY OF THE INVENTION

To improve the accuracy of the frequency of the local oscillation signal output from the local oscillator, the ratio of the highest oscillation frequency to the lowest oscillation frequency of the local oscillation signal must be controlled to 3:1 or less, preferably 2:1 or less. Therefore, the abovementioned tuner requires three local oscillators and resonance circuits for UHF, VHF high-band and VHF low-band channels, whereby the tuner becomes bulky and costs dear. The present invention has been made in view of the above situation and an object of the present invention is to provide a small-sized and inexpensive tuner.

To solve the above problem, according to a first aspect of the present invention, there is provided a TV signal receiving tuner for receiving TV signals by dividing them into a plurality of frequency bands, comprising a local oscillator which oscillates at a frequency range corresponding to a TV signal having a predetermined frequency band, a first programmable divider which receives a local oscillation signal of the local oscillator and divides the local oscillation signal, and a first mixer which mixes the received TV signal and the output of the first programmable divider and frequency converts the received TV signal into an intermediate-frequency signal having a predetermined frequency, wherein the dividing rate of the first programmable divider is variable and set to 1 to receive the TV signal having a predetermined frequency band and to 1/2 or less to receive a TV signal having a frequency band lower than the predetermined frequency band.

According to a second aspect of the present invention, there is provided a TV signal receiving tuner for receiving TV signals by dividing them into a plurality of frequency bands, comprising a local oscillator which oscillates at a frequency range corresponding to a TV signal having a predetermined frequency band, a second programmable divider which receives a local oscillation signal of the local oscillator and divides the local oscillation signal, a second mixer which mixes the received TV signal and the local oscillation signal and frequency converts the received TV signal into an intermediate-frequency signal having a predetermined frequency, and a third mixer which mixes the received TV signal and the output of the second programmable divider and frequency converts the received TV signal into an intermediate-frequency signal having a predetermined frequency, wherein frequency conversion is carried out by the second mixer to receive the TV signal having a predetermined frequency band, and wherein frequency conversion is carried out by the third mixer to receive the TV signal having a frequency band lower than the above predetermined frequency band.

According to a third aspect of the present invention, there is provided a TV tuner wherein a dividing rate of the second programmable divider is variable and changed according to an area where it is used.

According to a fourth aspect of the present invention, there is provided a TV tuner wherein a first tracking filter for selecting the TV signal having a predetermined frequency band and a second tracking filter for selecting the TV signal having a frequency band lower than the predetermined frequency band are arranged in parallel to each other, wherein a PLL IC for outputting a tuning voltage for changing the frequency of the local oscillation signal output from the local oscillator is provided, and wherein the tuning voltage is applied to the first tracking filter and the second tracking filter to tune a pass band of the first tracking filter or the second tracking filter to a frequency of the TV signal to be received.

According to a fifth aspect of the present invention, there is provided a TV tuner wherein the first tracking filter and the second tracking filter are a multi-tuning circuit.

According to a sixth aspect of the present invention, there is provided a TV tuner wherein a low-noise first preamplifier having an AGC function is provided after the first tracking filter, and wherein a low-noise second preamplifier having an AGC function is provided after the second tracking filter.

According to a seventh aspect of the present invention, there is provided a TV tuner wherein a first image trap circuit for attenuating an image frequency signal corresponding to a TV signal to be received is interposed between the first preamplifier and the second mixer, and wherein a second image trap circuit for attenuating an image frequency signal corresponding to a TV signal to be received is interposed between the second preamplifier and the third mixer.

According to an eighth aspect of the present invention, there is provided a TV tuner wherein the local oscillator outputs an oscillation signal having a frequency band of at least 847 to 505 MHz, and wherein the dividing rate of the first programmable divider can be changed to at least 1, 1/3 and 1/5.

According to a ninth aspect of the present invention, there is provided a TV tuner wherein the local oscillator outputs an oscillation signal having a frequency band of at least 803 to 473 MHz, and wherein the dividing rate of the first programmable divider can be changed to at least 1, 1/3 and 1/9.

According to a tenth aspect of the present invention, there is provided a TV tuner wherein the local oscillator outputs an oscillation signal having a frequency band of at least 824 to 530 MHz, and wherein the dividing rate of the first programmable divider can be changed to at least 1, 1/3 and 1/4.

According to an eleventh aspect of the present invention, there is provided a TV tuner wherein the local oscillator outputs an oscillation signal having a frequency band of at least 767 to 473 MHz, and wherein the dividing rate of the first programmable divider can be changed to at least 1, 1/3 and 1/6.

According to a twelfth aspect of the present invention, there is provided a TV tuner comprising a third programmable divider for receiving the oscillation signal of the local oscillator and dividing the oscillation signal and a fourth mixer for mixing the received TV signal and the output of the third programmable divider and frequency converting the received TV signal into an intermediate-frequency signal having a predetermined frequency, wherein the local oscillator outputs an oscillation signal having a frequency band of at least 847 to 505 MHz, wherein the dividing rate of the second programmable divider is 1/3, and wherein the dividing rate of the third programmable divider is 1/5.

According to a thirteenth aspect of the present invention, there is provided a TV tuner comprising a third programmable divider for receiving the oscillation signal of the local oscillator and dividing the oscillation signal and a fourth mixer for mixing the received TV signal and the output of the third programmable divider and frequency converting the received TV signal into an intermediate-frequency signal having a predetermined frequency, wherein the local oscillator outputs an oscillation signal having a frequency band of at least 803 to 473 MHz, wherein the dividing rate of the second programmable divider is 1/3, and wherein the dividing rate of the third programmable divider is 1/9.

According to a fourteenth aspect of the present invention, there is provided a TV tuner comprising a third programmable divider for receiving the oscillation signal of the local oscillator and dividing the oscillation signal and a fourth mixer for mixing the received TV signal and the output of the third programmable divider and frequency converting the received TV signal into an intermediate-frequency signal having a predetermined frequency, wherein the local oscillator outputs an oscillation signal having a frequency band of at least 824 to 530 MHz, wherein the dividing rate of the second programmable divider is 1/3, and wherein the dividing rate of the third programmable divider is 1/4.

According to a fifteenth aspect of the present invention, there is provided a TV tuner comprising a third programmable divider for receiving the oscillation signal of the local oscillator and dividing the oscillation signal and a fourth mixer for mixing the received TV signal and the output of the third programmable divider and frequency converting the received TV signal into an intermediate-frequency signal having a predetermined frequency, wherein the local oscillator outputs an oscillation signal having a frequency band of at least 767 to 473 MHz, wherein the dividing rate of the second programmable divider is 1/3, and wherein the dividing rate of the third programmable divider is 1/6.

The other objects and advantages of the present invention will become obvious from the following description.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The tuner of the present invention will be described hereinbelow with reference to FIG.1and FIG.2. The tuner receives TV signals by dividing them into UHF (806 to 470 MHz in the U.S.), VHF high-band (216 to 174 MHz in the U.S.) and VHF low-band (88 to 54 MHz in the U.S.) signals.

The tuner shown inFIG. 1comprises an input terminal2connected to an antenna1, a first tracking filter3, a first high-frequency amplifier6, a second tracking filter4, a second high-frequency amplifier7, a third tracking filter5, a third high-frequency amplifier8, a first mixer9, a filter13, an intermediate-frequency amplifier14, an output terminal15of the tuner, a first programmable divider16, a local oscillator19, a PLL IC20, a quartz oscillator21and a resonance circuit22.

To receive a UHF TV signal, a band selection signal Vu for receiving UHF is output from the PLL IC20, a band selection signal Vhi for receiving VHF high-band and a band selection signal Vlo for receiving VHF low-band are not output, the first preamplifier6is activated and the second preamplifier7and the third preamplifier9are not activated. In this state, a TV signal received by the antenna1is tuned by the first tracking filter3and amplified by the first preamplifier6. The first tracking filter3is a multi-tuning circuit and its tuning frequency is changed by a tuning voltage Vt output from the PLL IC20and tuned to the frequency band of a channel to be received. Since the first preamplifier6is a low-noise amplifier having an AGC function, even when a signal applied to the first preamplifier6is at a low level, NF does not deteriorate. Therefore, even when the first tracking filter3having high input impedance is connected after the antenna1having low output impedance, the NF of the output of the first preamplifier6does not deteriorate.

To receive a VHF high-band TV signal, a band selection signal Vhi for receiving VHF high-band is output from the PLL IC20, a band selection signal Vu for receiving UHF and a band selection signal Vlo for receiving VHF low-band are not output, the second preamplifier7is activated, and the first preamplifier6and the third preamplifier8are not activated. In this state, a TV signal received by the antenna1is tuned by the second tracking filter4and amplified by the second preamplifier7. The second tracking filter4is a multi-tuning circuit and its tuning frequency is changed by a tuning voltage Vt output from the PLL IC20and tuned to the frequency band of a channel to be received. Since the second preamplifier7is a low-noise amplifier having an AGC function, even when the signal input into the second preamplifier7is at a low level, NF does not deteriorate. Therefore, even when the second tracking filter4having high input impedance is connected after the antenna1having low output impedance, NF of the output of the second preamplifier7does not deteriorate.

To receive a VHF low-band TV signal, a band selection signal Vlo for receiving VHF low-band is output from the PLL IC20, a band selection signal Vu for receiving UHF and a band selection signal Vhi for receiving VHF high-band are not output, the third amplifier8is activated, and the first preamplifier6and the second preamplifier7are not activated. In this state, a TV signal received by the antenna1is tuned by the third tracking filter5and amplified by the third preamplifier8. The third tracking filter5is a multi-tuning circuit and its tuning frequency is changed by a tuning voltage Vt output from the PLL IC20and tuned to the frequency band of a channel to be received. Since the third preamplifier8is a low-noise amplifier having an AGC function, even when the signal input into the third preamplifier8is at a low level, NF does not deteriorate, Therefore, even when the third tracking filter5having high input impedance is connected after the antenna1having low output impedance, NF of the output of the third preamplifier8does not deteriorate.

The TV signal output from the first preamplifier6, the second preamplifier7or the third preamplifier8is applied to the first mixer9. The first mixer9mixes the TV signal and a local oscillation signal having a frequency 44 MHz higher than the TV signal and outputs a 44 MHz intermediate-frequency signal.

The intermediate-frequency signal is applied to the filter13. The filter13is a band-pass filter having sharp characteristics and connected to the intermediate-frequency amplifier14. The intermediate-frequency signal amplified by the intermediate-frequency amplifier14is output from the output terminal15of the tuner.

The local oscillation signal output from the local oscillator19is applied to the first mixer9after it is divided by the first programmable divider16. The frequency of the local oscillation signal is controlled by a tuning voltage Vt, a band selection signal Vhi for receiving VHF high-band and a band selection signal Vlo for receiving VHF low-band which are applied to the resonance circuit22. To receive a UHF channel, a band selection signal Vhi for receiving VHF high-band and a band selection signal Vlo for receiving VHF low-band are not applied to the resonance circuit22, switch diodes23aand23bare off, and the local oscillator19outputs a local oscillation signal having a frequency of 847 to 517 MHz. To receive a VHF high-band channel, a band selection signal Vhi for receiving VHF high-band is applied to the resonance circuit22, the switch diode23ais turned on to activate a capacitor24a, a band selection signal Vlo for receiving VHF low-band is not applied to turn off the switch diode23b, and the local oscillator19outputs a local oscillation signal having a frequency of 771 to 663 MHz. To receive a VHF low-band channel, a band selection signal Vlo for receiving VHF low-band is applied to the resonance circuit22, the switch diode23bis turned on to activate a capacitor24b, a band selection signal Vhi for receiving VHF high-band is not applied to turn off the switch diode23a, and the local oscillator19outputs a local oscillation signal having a frequency of 645 to 505 MHz.

The local oscillation signal output from the local oscillator19is output to the first programmable divider16and the PLL IC20. The PLL IC20compares the local oscillation signal output from the local oscillator19with a reference oscillation signal output from the quartz oscillator21and controls a tuning voltage Vt to adjust the frequency of the reference oscillation signal to a predetermined frequency. One of the band selection signals Vu, Vhi and Vlo is applied to the first programmable divider16from the PLL IC20. To receive a UHF channel TV signal, the band selection signal Vu for receiving UHF is applied to the first programmable divider16, the dividing rate of the first programmable divider16is set to 1, and the local oscillation signal applied to the first programmable divider16is directly output to the first mixer9. To receive a VHF high-band channel TV signal, the band selection signal Vhi for receiving VHF high-band is applied to the first programmable divider16, the dividing rate of the first programmable divider16is set to 1/3, and the local oscillation signal applied to the first programmable divider16is divided to generate a signal having a frequency 1/3 that of the local oscillation signal which is then output to the first mixer9. To receive a VHF low-band channel TV signal, the band selection signal Vlo for receiving VHF low-band is applied to the first programmable divider16, the dividing rate of the first programmable divider16is set to 1/5, and the local oscillation signal applied to the first programmable divider16is divided to generate a signal having a frequency 1/5 that of the local oscillation signal which is then output to the first mixer10.

In the above embodiment, the intermediate frequency is 44 MHz. When the intermediate frequency is 0 Hz, to receive a UHF channel, the local oscillator19is oscillated at 803 to 473 MHz, and the dividing rate of the first programmable divider16is set to 1. To receive a VHF high-band channel, the local oscillator19is oscillated at 639 to 531 MHz and the dividing rate of the first programmable divider16is set to 1/3. To receive a VHF low-band channel, the local oscillator19is oscillated at 765 to 513 MHz and the dividing rate of the first programmable divider16is set to 1/9.

When the TV tuner of the present invention is used in products to be marketed in Japan, as the UHF band is 770 to 470 MHz, the VHF high-band is 222 to 170 MHz and the VHF low-band is 108 to 90 MHz and the intermediate frequency is generally 57 MHz. Therefore, to receive a UHF channel, the local oscillator19is oscillated at 824 to 530 MHz and the dividing rate of the first programmable divider16is set to 1. To receive a VHF high-band channel, the local oscillator19is oscillated at 810 to 690 MHz and the dividing rate of the first programmable divider16is set to 1/3, To receive a VHF low-band channel, the local oscillator19is oscillated at 648 to 600 MHz and the dividing rate of the first programmable divider16is set to 1/4.

Further, when the intermediate frequency is set to 0 Hz in products to be marketed in Japan, to receive a UHF channel, the local oscillator19is oscillated at 767 to 473 MHz and the dividing rate of the first programmable divider is set to 1. To receive a VHF high-band channel, the local oscillator19is oscillated at 657 to 519 MHz and the dividing rate of the first programmable divider16is set to 1/3. To receive a VHF low-band channel, the local oscillator19is oscillated at 630 to 558 MHz and the dividing rate of the first programmable divider16is set to 1/6.

FIG. 2shows another embodiment of the tuner of the present invention. This tuner uses a plurality of mixers for different frequency bands to carry out frequency conversion. The same elements as inFIG. 1are given the same reference numerals and their descriptions are omitted.

A nation identification signal Vc is output from the, PLL IC20to a second programmable divider17and a third programmable divider18. In the case of products to be marketed in the U.S., when the tuner is powered on, the dividing rate of the second programmable divider17is set to 1/3 and the dividing rate of the third programmable divider18is set to 1/5.

To receive a UHF channel TV signal, the TV signal output from the first preamplifier6is applied to a second mixer10after an image frequency signal is attenuated by a first image trap26. The local oscillation signal is directly applied to the second mixer10from the local oscillator19so that the frequency of the TV signal is converted into an intermediate frequency of 44 MHz by the local oscillation signal.

To receive a VHF high-band channel TV signal, the TV signal output from the second preamplifier7is applied to a third mixer11after an image frequency signal is attenuated by a second image trap27. The local oscillation signal output from the local oscillator19is applied to the third mixer11after its frequency is divided to 1/3 by the second programmable divider17so that the frequency of the TV signal is converted into an intermediate frequency of 44 MHz by the local oscillation signal.

To receive a VHF low-band channel TV signal, the TV signal output from the third preamplifier8is applied to a fourth mixer12after an image frequency signal is attenuated by a third image trap28. The local oscillation signal output from the local oscillator19is applied to the fourth mixer12after its frequency is divided to 1/5 by the third programmable divider18so that the frequency of the TV signal is converted into an intermediate frequency of 44 MHz by the local oscillation signal.

To use this tuner in products to be marketed in Japan, a nation identification signal Vc output from the PLL IC20is converted into a code indicative of Japan and output to the second programmable divider17and the third programmable divider18, and the dividing rate of the second programmable divider17is set to 1/3 and the dividing rate of the third programmable divider18is set to 1/5 when the tuner is powered on.

To receive a UHF channel, a local oscillation signal having a frequency of 824 to 530 MHz is output from the local oscillator19. To receive a VHF high-band channel, the local oscillator19is oscillated at 810 to 690 MHz and the dividing rate of the second programmable divider17is set to 1/3. To receive a VHF low-band channel, the local oscillator19is oscillated at 648 to 600 MHz and the dividing rate of the third programmable divider18is set to 1/4.

In the above embodiment, the intermediate frequency is 44 MHz. When the intermediate frequency is 0 Hz, the dividing rate of the second programmable divider17is set to 1/3 and the dividing rate of the third programmable divider18is set to 1/9. To receive a UHF channel, the local oscillator19is oscillated at 803 to 473 MHz. To receive a VHF high-band channel, the local oscillator19is oscillated at 639 to 531 MHz. To receive a VHF low-band channel, the local oscillator19is oscillated at 765 to 513 MHz.

When this tuner is used in TVs to be marketed in Japan, the dividing rate of the second programmable divider17is set to 1/3 and the dividing rate of the third programmable divider18is set to 1/6. To receive a UHF channel, the local oscillator19is oscillated at 767 to 473 MHz. To receive a VHF high-band channel, the local oscillator19is oscillated at 657 to 519 MHz and to receive a VHF low-band channel, the local oscillator19is oscillated at 630 to 558 MHz.

As described above, the TV receiving tuner of the present invention can output an oscillation signal having a wide frequency band by means of one local oscillator and can be made small in size and inexpensive by using one or a plurality of dividers.

Since the dividing rate of the programmable divider is variable and is changed according to the area where it is used in the TV receiving tuner of the present invention, the same tuner can be used in different areas which differ in TV receiving frequency.

Since a tuning voltage for changing the frequency of the local oscillation signal of the local oscillator is applied to the tracking filter to tune the pass band of the tracking filter to the frequency of the TV signal in the TV receiving tuner of the present invention, the pass band of the tracking filter changes according to the frequency of the local oscillation signal of the local oscillator.

Since the tracking filter is a multi-tuning circuit in the TV receiving tuner of the present invention, characteristics on the inlet side and characteristics on the outlet side can be designed separately, thereby making it easy to adjust input and output characteristics to circuits before and after the input and outlet sides. Since the attenuation of a signal having an unrequired frequency is large, cross modulation hardly occurs in the mixer.

Since a low-noise preamplifier having an AGC function is interposed between the tracking filter and the mixer in the TV receiving tuner of the present invention, a mono-tuning circuit is not necessary, thereby making it possible to reduce the size of the tuner.

Since a trap circuit for attenuating an image frequency is provided in the TV receiving tuner of the present invention, the noise of the received signal is reduced.

Since the local oscillator can be oscillated at 847 to 505 MHz and the dividing rate of the first programmable divider can be changed to 1, 1/3 or 1/5 in the TV receiving tuner of the present invention, the TV signal of the U.S. can be converted into an intermediate-frequency signal having a frequency of 44 MHz.

Since the local oscillator can be oscillated at 803 to 473 MHz and the dividing rate of the first programmable divider can be changed to 1, 1/3 or 1/9 in the TV receiving tuner of the present invention, the TV signal of the U.S. can be converted into an intermediate-frequency signal having a frequency of 0 Hz.

Since the local oscillator can be oscillated at 824 to 530 MHz and the dividing rate of the first programmable divider can be changed to 1, 1/3 or 1/4 in the TV receiving tuner of the present invention, the TV signal of Japan can be converted into an intermediate-frequency signal having a frequency of 57 MHz.

Since the local oscillator can be oscillated at 767 to 473 MHz and the dividing rate of the first programmable divider can be changed to 1, 1/3 or 1/6 in the TV receiving tuner of the present invention, the TV signal of Japan can be converted into an intermediate-frequency signal having a frequency of 0 Hz.

Since the local oscillator is oscillated at 847 to 505 MHz, the dividing rate of the second programmable divider is set to 1/3 and the dividing rate of the third programmable divider is set to 1/5 in the TV receiving tuner of the present invention, the TV signal of the U.S. can be converted into an intermediate-frequency signal having a frequency of 44 MHz.

Since the local oscillator is oscillated at 803 to 473 MHz, the dividing rate of the second programmable divider is set to 1/3 and the dividing rate of the third programmable divider is set to 1/9 in the TV receiving tuner of the present invention, the TV signal of the U.S. can be converted into an intermediate-frequency signal having a frequency of 0 Hz.

Since the local oscillator is oscillated at 824 to 530 MHz, the dividing rate of the second programmable divider is set to 1/3 and the dividing rate of the third programmable divider is set to 1/4 in the TV receiving tuner of the present invention, the TV signal of Japan can be converted into an intermediate-frequency signal having a frequency of 57 MHz.

Since the local oscillator is oscillated at 767 to 473 MHz, the dividing rate of the second programmable divider is set to 1/3 and the dividing rate of the third programmable divider is set to 1/6 in the TV receiving tuner of the present invention, the TV signal of Japan can be converted into an intermediate-frequency signal having a frequency of 0 Hz.