MXPA98003320A - High frequency electronic device - Google Patents

Abstract

In the present invention, a high frequency electronic device is described: the high frequency electronic device has a modulation part having an oscillator, and a tuner part having a high frequency unit for selecting a television signal which is to be received and produced therefrom, a mixer to effect frequency conversion on the selected television signal produced from the high frequency unit, and a local oscillator to send a local oscillation signal to the mixer; a high frequency unit has a tuner circuit between stages to send the selected television signal to the mixer, a low pass filter is electrically connected between the inter-stage tuner circuit and the mixer, so that a low-pass filter interrupting frequency is adjusted to a level higher than the maximum frequency of the television signal received by the unit high frequency, due to the above construction, the interference signals developed by an oscillation signal produced from the modulation part, and an oscillation signal produced from the tuner part for when the modulation part and the tuner part are activities simultaneously, they can be controlled at a low level to improve the quality of an image

Description

HIGH FREQUENCY ELECTRONIC DEVICE BACKGROUND OF THE INVENTION FIELD OF LR INVENTION This invention relates to a high-frequency electronic device, characterized in that a modulation part and a tuner part are configured within a single-channel housing.

DESCRIPTION OF THE RELATED TECHNIQUE A high-frequency electronic device having a modulation pad and a tuner provided within an individual me + ai housing has been used in a recent video recorder (hereinafter referred to as "VTR"). Figure 4 is a block diagram describing this type of high frequency electronic device of the prior art. In Figure 4, a high frequency electronic device 41 comprises a modulation part 44 and a tuner part 45 mounted on a printed circuit board 43 maintained within an individual metal housing 42. The modulation part 44 includes a distributor 46, a mixer 47, a modulator 48, a PLL 49 circuit, etc. On the other hand, the tuner part 45 includes a high frequency VHF 50 unit, a VHF 51 mixer, a local VHF oscillator. 52, a UHF 53 high frequency unit, a UHF mixer 54, a local UHF oscillator 55, an intermediate frequency amplifier 56, etc. In addition, an input terminal 57 and an output terminal 58 In addition, the modulating part 44 and the sintering part 45 are protected from each other by a protective plate 59 electrically connected to the metal housing 42. A television signal sent to the entry terminal 57 is sent to a television receiver not illustrated from the output terminal 58 through the distributor 46 and the mixer 47. Moreover, the television signal distributed by the distributor 46 is sent to the high frequency unit of VHF 50 and the UHF high frequency unit 53 of the tuner part 45. In addition, the PLL circuit 49 of the modulation part 44 is provided with a voltage controlled oscillator (referred to as forward "VCO") to produce a carrier signal not illustrated. The carrier signal produced from the VCO is modulated by the modulator 48 based on a video signal or its like reproduced by a VTR not illustrated. The modulated signal is sent to the television receiver not illustrated through the mixer 47 and the output terminal 58 as a television signal. In addition, the frequency of the carrier signal produced from the VCO is controlled by the PLL circuit 49 to match the frequency of a predetermined video carrier signal received by the television receiver. However, the present frequency is normally adjusted to the frequency of a channel not used for a transmission in the area where the VTR is used. On the other hand, the VHF high frequency unit 50 of the tuner part 45 selects a television signal on a desired channel from television signals in a VHF band. Similarly, the UHF high frequency unit 53 of the tuner part 45 selects a television signal on a desired channel from television signals in a UHF band. Although not shown in the drawing, each of the high frequency units of VHF 50 and the high frequency unit of UHF 53 has an input tuning circuit formed by a tuned individual circuit, a high frequency amplifier, a tuner circuit in re stages formed by a tuned double circuit, etc. The television signals in the selected channels are sent from their inter-stage tuner circuits to the VHF mixer 51 and the UHF mixer 54, respectively. Then, the television signals are mixed with local oscillation signals produced from the local VHF oscillator 52 and the local UHF oscillator., so that the combined signal is converted into frequency in an intermediate frequency signal, after which it is sent to a subsequent stage circuit not illustrated through the intermediate frequency amplifier 56. However, in the electronic device of high frequency of the prior art, a supply voltage is always applied to the modulation part 44 and the tuner part 45 without considering the VTR is set to record or play when the electronic high frequency device is able to be integrated in the VTR. Therefore, a harmonic of an oscillation signal (carrier wave) produced from the VCO of the PLL circuit 49 in the modulation part 44 easily jumps in the high frequency unit of VHF 50 or the high frequency unit of UHF 53 of the tuner part 45. The displaced harmonica is sent to the VHF mixer 51 and the UHF mixer 54 through the high frequency unit of VHF 50 or the high frequency unit of UHF 53. The harmonic is mixed with a harmonic of a local oscillation signal produced from the local VHF oscillator 52 or the local UHF oscillator 55 by the VHF mixer 51 or the UHF mixer 54. As a result, a problem arises because an interference signal is produced of a frequency extremely close to that of the intermediate frequency signal. The example described above confronting the problem will be explained for cases where the high frequency electronic device of the prior art is used in a VTR whose output channel is set to a channel 32 (i.e., a carrier signal produced from the VCO in the modulation part 44 is adjusted to the channel frequency 32) and which is placed below European specifications such as German specifications, and a channel 26 is registered by the VTR. In this case, the channel 26 used in the European television system corresponds to a band of UHF. The UHF oscillator-local 55 of the tuner part 45 in the high frequency electronic device 41 produces a local oscillation signal of 550.15flHz. On the other hand, since the output channel of the VTR is set to channel 32, the VCO of the PLL circuit 49 in the modulation part 44 oscillates at 559.25MHz. Although the two oscillation signals are sent to the UHF 54 mixer, their harmonics are also sent to it. In addition, the frequency corresponding to the difference between a fourth harmonic (2237MHz) of an oscillation signal produced from the VCO and a fourth harmonic (2200.6MHz) of an oscillation signal produced from the local oscillator of UHF 55 results in 36.4 MHz. This frequency (36.4MHz) is between an intermediate frequency of video (38.9MHz) and an intermediate frequency of conversation or voice (33.4MHz) used in a television system placed under European specifications, resulting in an interference signal against the normal receiver channel 26. As a result, the quality of an image for the recorded television signal deteriorates. The interference signals based on the relationships described above will occur in accordance with many combinations, such as where the VTR output channel is set to channel 63 when the receiver channel corresponds to channel 26, where the VTR output channel is adjusts to a channel 44 or 54 when the receiver channel corresponds to a channel 38, where the output channel of the VTR is set to a channel 22 or 52 when the receiving channel corresponds to a channel 46, etc.

BRIEF DESCRIPTION OF THE INVENTION Considering the above problems, it is therefore an object of this invention to provide a high frequency electronic device, wherein interference signals developed by an oscillation signal produced from a modulation part, and an oscillation signal produced from a part of tuner for when the modulation part and the tuner part are activated simultaneously, can be controlled at a low level, to improve the quality of an image. In accordance with an aspect of this invention, to achieve the above objective, a high frequency electronic device is provided, comprising: a metal housing; a printed circuit board maintained within the metal housing; a modulation part formed on the printed circuit board and having an oscillator; and a tuner part including a high frequency portion formed on the printed circuit board, for selecting a television signal to be received from television signals, and producing the selected television signal, a mixer for - frequency conversion in the selected television signal produced from the high frequency portion, and a local oscillator to supply a local oscillation signal to the mixer, wherein the high frequency portion has a tuner circuit between stages to send the signal of television selected to the mixer, and wherein a low pass filter is connected between the interstage tuner circuit and the mixer, such that an interrupting frequency thereof is adjusted so that it is greater than the maximum frequency of the signal television received by the high frequency portion. Preferably, in the high frequency electronic device of the present invention, the high frequency portion includes a high frequency UHF unit for selecting a television signal in a UHF band to be received from television signals. In the UHV band, and producing the selected television signal, the mixer includes a UHF mixer to effect frequency conversion on the selected television signal produced from the UHF high frequency unit, the local oscillator includes a local oscillator. UHF to supply a local oscillation signal to the UHF mixer, the UHF high frequency unit includes a UHF inter-stage tuner circuit to send the selected television signal in the UHF band to the UHF mixer, and the pass filter low is electrically connected between at least the tuner circuit between UHF stages and the UHF mixer. Preferably, in the high frequency electronic device of the present invention, the low pass filter comprises a L-type low pass filter formed by an inductor element and a capacitor element electrically connected between one end of the inductor element and ground. Preferably, in the high frequency electronic device of the present invention, the low pass filter comprises a low-pass filter derived from type M formed by an inductor element and a capacitor electrically connected in parallel to each other, and a capacitor-connected element electrically between one of the ends of the inductor element connected mutually in parallel and to the capacitor and ground. Preferably, in the high frequency electronic device of the present invention, the capacitor element is formed by a dispersed capacitance formed between two conductive patterns provided on the printed circuit board.

BRIEF DESCRIPTION OF THE DRAWINGS Even when the specification concludes with claims that particularly point out and claim differently the matter that is considered as the invention, it is thought that the invention, the objectives and characteristics of the invention, and other objectives, characteristics and advantages of the present will be understood better from the following description considered in connection with the accompanying drawings, in which: Figure 1 is a block diagram showing a high frequency electronic device of the present invention; Figure 2 is a circuit diagram illustrating a low pass filter used in the high frequency electronic device of the present invention; Figure 3 is a diagram describing a method for forming a low pass filter capacitor used in the high frequency electronic device of the present invention; and Figure 4 is a block diagram showing a conventional high frequency electronic device.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES Next, a high frequency electronic device of the present invention will be described in relation to FIGS. 1 to 3. First of all, FIG. 1 is a block diagram showing the high frequency electronic device of the present invention. The high frequency electronic device 1 comprises a modulation part 4 and a tuner part 5 mounted or installed on a printed circuit board 3 held within a single metal housing 2. Furthermore, the modulation part 4 includes a distributor 6. , a mixer 7, a modulator 8, a PLL circuit 9, etc. The PLL circuit 9 has a voltage controlled oscillator (referred to as forward "VCO") 10 which functions as an oscillator to generate a carrier signal. On the other hand, the tuner part * 5 comprises a high frequency VHF unit 11 which functions as a high frequency section for selecting and producing a television signal located within a VHF band to be received from signals television in the VHF band, a VHF mixer 12 that functions as a mixer to convert the television signal in the VHF band produced from the high frequency VHF unit 11 into an intermediate frequency signal and produces the signal intermediate frequency, a local VHF oscillator 13 that functions as a local oscillator to supply a local oscillation signal to the VHF mixer 12, a high frequency unit of UHF 14 that functions as a high frequency section to select and produce a television signal located in a UHF band that will be received from television signals in the UHF band, a UHF 15 mixer that works as a mixer for frequency converting the television signal in the UHF band produced from the high frequency unit of UHF 14 into an intermediate frequency signal and producing the intermediate frequency signal, a local oscillator of UHF 16 that functions as a local oscillator for supplying a local oscillation signal to the UHF mixer 15, an intermediate frequency amplifier 17 for amplifying the intermediate frequency signal produced from the VHF mixer 12 or the UHF mixer 15, etc. In addition, the high frequency unit of VHF 11 and the high frequency unit of UHF 14 each have an input tuner circuit, a high frequency amplifier, a tuner circuit between stages, etc. In addition, a low pass filter 18 and a second low pass filter 19 are respectively provided between the high frequency unit of VHF 11 and the VHF mixer 12 and between the high frequency unit of UHF 14 and the mixer UHF 15. Now, the VHF high frequency unit 11 is configured in such a way that a VHF input tuning circuit 20, a VHF high frequency amplifier 21 and a VHF inter-stage tuner circuit 22 are sequentially connected to each other. each. In addition, the high frequency unit of UHF 14 is also constructed so that a tuner circuit * of UHF 23, a high frequency amplifier of UHF 24 and a tuner cell between UHF stages 25 are successively electrically connected between yes. The first low-pass filter 18 is electrically connected to the tuner-inter-VHF circuit 22 of the VHF high-frequency unit 11 and the VHF mixer 12, while the second pass-through filter ba 19 is electrically connected. to the UHF inter-step tuner circuit 25 of the UHF high-frequency unit 14 and the UHF mixer 15. The first low-pass filter 18 comprises a M-type derived filter, and has a first inductor 2b and a first capacitor 27 electrically connected in parallel to each other, and a second capacitor 28 operating as a capacitor element electrically connected between one of the ends of the first inductor element 26 connected in parallel and the first capacitor 27 and to ground. In the same way, the second low pass filter 19 also comprises a M-type derived filter, and includes a second inductor element 29 and a third capacitor JO electrically connected in parallel to each other, and a fourth capacitor 31 operating as a capacitor element electrically connected between one of the ends of the second inductor element 29 connected in parallel and the third capacitor 30 and ground. The first low pass filter 18 allows a television signal having the highest or maximum frequency (230 MHz in the European television system), of the television signals in the VHF band received by the high frequency unit. of VHF 11, pass through them and thus adjust an interruption frequency thereof between 1000 MHz and 1500 MHz, for example, in order to attenuate a signal of a frequency greater than the maximum frequency. In addition, the second low-pass filter 19 allows a television signal having the maximum frequency (corresponding to 862 MHz in the European television system), of the television signals in the UHF band received by the television unit. High frequency of UHF 14, pass through the same and thus adjust an interruption frequency thereof between 1500 MHz and 2000 MHz, for example, in order to attenuate a signal having a frequency greater than the maximum frequency. Therefore, the VHF mixer 12 is blocked from the input of signals of frequency greater than about 1000 MHz to 1500 MHz, each corresponding to the interruption frequency. Alternatively, even when the signals are sent to the VHF mixer 12, they are controlled at a low level. Similarly, the UHF mixer 15 is blocked from the input of signals having frequencies above about 1500 MHz to 2000 MHz. Alternatively, even when the signals are sent to the mixer * of UHF 15, they are controlled at a low level. Incidentally, in accordance with the present invention, an input terminal 32 and an output terminal 33 are attached to the metal housing 2 of the high frequency electronic device 1. In addition, the modulation part 4 and the tuning part 5 are n protected from each other by a protective plate 34 electrically connected to the metal housing 2. A television signal input for the input terminal 32 is sent by the distributor 6 and the mixer 7 from the output terminal 33 to a television receiver not illustrated, where the television signal can be observed. On the other hand, the television signal distributed by the distributor 6 is going to be sent to the VHF high frequency unit 11 and the UHF high frequency unit 14 of the tuner part 5. In addition, an oscillation signal produced from the VCO 10 of the PLL circuit 9 of the modulation part 4 is set as a serial carrier. The carrier signal is modulated by the modulator 8 based on a video signal or its like * reproduced by a VTR not illustrated, with the high frequency electronic device 1 incorporated therein. Then, the modulated signal is sent to the television receiver not illustrated through the mixer 7 and the output terminal 33 as a television signal. Thus, the frequency of the carrier signal produced from the VCO 10 is coupled with the frequency of a predetermined video carrier signal corresponding to a channel determined by a television system, so that it can be received by the television receiver. Therefore, the VCO 10 is controlled in PLL by its coupling. The frequency of the carrier signal is generally adjusted to the frequency of a channel not used for a transmission in the area where the VTR is used. However, this frequency can be adjusted to the frequency of an arbitrary channel through the PLL 9 circuit. On the other hand, the high frequency unit of VHF 11 of the tuner part 5 selects a television signal on the desired channel from the television signals in the VHF band. In the same way, the UHF high frequency unit 14 selects a television signal on a desired channel from the television signals in the UHF band. The selected television signal in the VHF band is output from the VHF inter-step tuner circuit 22, after which it is sent to the VHF mixer 12 through the first low-pass filter 18. At the same time, the signal of Television in the UHF band selected by the high frequency unit of UHF 14 is produced from the tuner circuit between stages of UHF 25, deepues of which is sent to the UHF mixer 15 through the second pass filter ba or 19. As described above, the first low pass filter 18 has the frequency of interruption adjusted to the frequency (e.g., 1500MHz) greater than the maximum frequency of the television signal in the VHF band received by the high frequency unit of VHF 11. Therefore, the VHF mixer 12 is blocked from the harmonic input above 1500MHz from the VCO 10 of the PLL circuit 9 in the modulation part 4, or the level of the harmonic is control at a low level even when the harmonic is sent to the VHF mixer 12. Similarly, the second low pass filter 31 has the frequency of interruption adjusted to the frequency (eg, 2000MHz) greater than the maximum frequency of the television signal in the UHF band received by the high frequency unit of UHF 14. Therefore, the UHF mixer 15 is blocked from the harmonic input above 2000MHz from the VCO 10 of the PLL circuit 9 in the part of modulation 4, or the level of the harmonic is controlled at a low level even when the harmonic is sent to the UHF mixer 15. The television signal in the VHF band sent to the VHF mixer 12 is mixed with a signal of local oscillation produced from the local VHF oscillator 13 by the VHF mixer 12, so that the television signal is converted into frequency in an intermediate frequency signal. Thus, the intermediate frequency output is sent to an unillustrated circuit located in the subsequent stage through the intermediate frequency amplifier 17. From the same time, the television signal in the UHF band sent to the UHF mixer 15 is mixed with a local oscillation signal produced from the local UHF oscillator 16 by the UHF mixer 15, so that the television signal is converted into frequency into an intermediate frequency signal. Thus, the converted intermediate frequency output is sent to the rear stage circuit not illustrated through the intermediate frequency amplifier 17. An unillustrated video tuner, and its like, are provided in the subsequent step to the intermediate frequency amplifier 17. A video signal demodulated by the video demodulator is recorded. Since the first low pass filter 18 is provided between the VHF inter-step tuner circuit 22 of the VHF high frequency unit 11 and the VHF mixer 12, and the second low pass filter 19 is provided between the tuner circuit between UHF stages 25 of the high frequency unit of UHF 14 and the UHF mixer 15 in the high frequency electronic device of the present invention as described above, it is difficult for the harmonic of the oscillation signal produced from the VCO 10 of the PLL circuit 9 in the modulation part 4 is sent to the VHF mixer 12 and the UHF mixer 15, so that the interference signals generated in the VHF mixer 12 and the UHF mixer 15 can be controlled to a very low level. If a comparison is made between the harmonic produced from the local oscillator of VHF 13 and the harmonic produced from the local oscillator of UHF 16, which are mixed with the harmonic of the oscillation signal produced from the VCO 10, to produce the interferential signals, then the degree of the harmonic produced from the local oscillator of UHF 16 is low and, consequently, the harmonic produced from the local UHF 16 oscillator comes to have a high level (in general, the level of each harmonic becomes high, as the degree of them decreases). Therefore, the interference signal is produced sharply from the UHF mixer 15, rather than from the VHF mixer 12. Thus, the provision of the second pass filter at least between the tuner circuit between stages of UHF. 25 of the high frequency unit of UHF 14 and the UHF mixer 15, allows to effectively prevent the appearance of the interference signals. The circuit configurations of the first low pass filter 18 and the second low pass filter 19 are not limited to the circuit configuration of the low pass filter of the M type shown in Figure 1. They can use constant type K filters such as type T, type ir, etc., or a low-pass filter of type L 35 shown in Figure 2, which is configured in a middle section of the constant filter of type K. Since the low-pass filter 35 can being simply formed of two parts of an inductor element 36 and a capacitor 37 corresponding to a capacitor element connected to ground, does not represent an extra space for the printed circuit board 3 maintained inside the metal housing 2. The coupling can simply be obtained of the impedance of the tuner cell between stages of VHF 22 with that of the VHF mixer 12, and the coupling of the impedance of the tuner circuit between stages of UHF 25 with that of the mix UHF 15. If the first low pass filter 18 and the second pass filter ba or 19 are configured as the derivative type M low pass filter shown in Figure 1, then the harmonics produced from the VCO can be attenuated. , which exist on a scale up to the vicinity of the interruption frequency. Therefore, many interference signals produced in the VHF mixer 12 or the UHF mixer 15 can be suppressed. Since either of the second capacitor 28 of the first p &g filterWhen the second capacitor 31 of the second low pass filter 19 shown in Fig. 1 and the capacitor 37 shown in Fig. 2 are used as the capacitor element connected to ground, these capacitors 28, 31 and 3 7 to be replaced with a dispersed capacitance 40 created between two conductive patterns 38 and 39 provided on a printed circuit board 3, as shown in Fig. 3. The coil 36 of the low-pass filter 35 shown in Fig. 2, e.g. electrically connected to a conductor pattern 38, and the other conductor pattern 39 can be electrically connected to the metal housing 2. Thus, if the dispersed capacitance 40 is used using the connection board 3, then the capacitor 37 can be eliminated. As described above, the high frequency electronic device according to the present invention includes a modulation part having an oscillator and a tuner part having a high frequency unit, a mixer and a local oscillator. The high frequency unit has a tuner circuit between stages. In addition, a low pass filter is electrically connected between the interstage tuner circuit and the mixer to adjust an interrupting frequency thereof at a frequency greater than the maximum frequency of a television signal received by the high frequency unit. Therefore, it is difficult for a harmonic of an oscillation signal produced from the oscillator of the modulation part to be sent to the mixer, so that an interference signal produced in the mixer can be controlled at an extremely low level. In accordance with the high frequency electronic device of the present invention, since the low pass filter is electrically connected between at least one tuner circuit between UHF stages and a UHF mixer, interference signals can be effectively prevented from occurring.

In accordance also with the high frequency electronic device of the present invention, since the low pass filter comprises a L-type low pass filter formed by an inductor element and a capacitor element, it can be simply made of two parts and not thus represents an extra space for a printed circuit board. In addition, the coupling of the impedance between the interstage tuner circuit and the mixer can be obtained in a simple manner. Furthermore, in accordance with the electronic high-frequency device of the present invention, since the pass filter is formed by a low-pass filter derived from type M, the harmonics produced from the oscillator of the modulation part, which They exist on a scale up to the vicinity of a low pass filter interrupt frequency can be * attenuated, so that many interference signals produced in the mixer can be suppressed. Furthermore, in accordance with the high frequency electronic device of the present invention, since a capacitor element of a low-pass filter to ground is formed by a dispersed capacitance formed between two conductive patterns provided on a printed circuit board the capacitor arrives to be unnecessary, so that the parts can be reduced in number. Although the present invention has been described in relation to the illustrative embodiment, this description is not intended to be constructed in a limiting sense. Several z > z > Modifications of the illustrative mode will be apparent to those skilled in the art in relation to this description. Therefore, it is contemplated that the appended claims will cover any such modifications or modalities that are within the true scope of the invention.

Claims (10)

NOVELTY OF THE INVENTION CLAIMS

1. - A high frequency electronic device, comprising: a metal housing; a printed circuit board maintained within said metal housing; a modulation part formed on said printed circuit board and having an oscillator; and a tuner part, which includes: a high frequency portion formed on said printed circuit board, for selecting a television signal to be received from television signals, and producing the selected television signal; a mixer for effecting frequency conversion on the selected television signal produced from said high frequency portion; and a local oscillator for supplying a local oscillation signal to said mixer, wherein said high frequency portion has a tuner circuit for sending the selected television signal to said mixer, and wherein a low pass filter is connected between said circuit tuner and said mixer, so that an interruption frequency thereof is adjusted so that it is greater than the maximum frequency of the television signal received by said high frequency portion.

2. A high-frequency electronic device according to claim 1, characterized in that said high-frequency portion includes a high-frequency UHF unit for selecting a television signal to be received from television signals in the UHV band, and producing the selected television signal, said mixer includes a UHF mixer for effecting-frequency conversion on the selected television signal produced from said UHF high frequency unit, said local oscillator includes a local oscillator of UHF for supplying a local oscillation signal to said UHF mixer, said UHF high frequency unit includes a UHF tuner circuit for sending the selected television signal to said UHF mixer, and said low pass filter is electrically connected between said UHF tuner circuit and said UHF mixer.

3. A high-frequency electronic device according to claim 2, characterized in that said low-pass filter comprises a L-type low-pass filter formed by an inductor element and a capacitor element electrically connected between one end of said inductor element and to earth.

4. A high-frequency electronic device according to claim 3, characterized in that said capacitor element is formed by a capacitance disperea formed between doe patronee drivers provided on said printed circuit board.

5. - A high-frequency electronic device according to claim 2, characterized in that said low-pass filter comprises a low-pass filter derived from type M formed by an inductor element and a capacitor electrically connected in parallel to each other, and a capacitor element electrically connected between one of the ends of said inductor element connected mutually in parallel and to the capacitor and ground.

6. A high-frequency electronic device according to claim 5, characterized in that said capacitor element is formed by a dispersed capacitance formed between two conductive patterns provided on said printed circuit board.

7. A high-frequency electronic device according to claim 1, characterized in that said low-pass filter comprises a pass filter ba or derivative of type L formed by an inductor element and a capacitor element electrically connected between one end of said Inductor element and ground.

8. A high-frequency electronic device according to claim 7, characterized in that said capacitor element is formed by a dispersed capacitance formed between two conductive patterns provided on said printed circuit board.

9. A high-frequency electronic device according to claim 1, characterized in that said pass filter ba comprises a low-pass filter derived from type M formed by an inductor element and a capacitor electrically connected in parallel to each other, and a capacitor element electrically connected between one of the ends of said inductor element. connected to each other in parallel and to the capacitor and ground.

10. A high-frequency electronic device according to claim 9, characterized in that said capacitor element is formed by a dispersed capacitance formed between two conductive patterns provided on said printed circuit board.