JPS6019393Y2 - Turret tuner - Google Patents

Description

[Detailed description of the invention] This invention is a turret type tuner that amplifies an intermediate frequency signal (hereinafter referred to as a UIF signal) when receiving an LJHF band chaff channel using a VHF tuner. The present invention relates to a turret tuner equipped with an input circuit that eliminates signal interference.

Traditionally, as a tuner that receives both the IJHF band chaff channel and the FHF medium channel, a method has been widely adopted in which the UIF signal output from the U+' tuner is amplified by the active element of the VHF tuner using a relay segment provided in the VHF tuner. ing.

This type of tuner, for example, has one relay segment for receiving U)(F band channels and 12 tuning segments for receiving VHFHF channels) arranged around the holder of the tuning axis. This is a so-called turret-type tuner that constitutes a rotatable drum-shaped turret body.

However, in the switching system at the input stage of this type of tuner, input signals of different reception bands are likely to be combined via stray capacitance, which may cause interfering waves to be caused by the LJIF signal when receiving the VHFHF middle channel.

That is, 1. U of fixed contact group to which UHFHF signal is supplied
IF input Kataka terminal VHFH where HF signal is input
Since the UH terminals are arranged close to each other in the input stage of the F terminal, they are in a predetermined relationship when receiving the VHFHF middle channel.
When the F signal jumps in, beat interference occurs.

For example, channels 12 of the VHF band in the U, S, and S channels have beat interference with their third harmonic and channel 54 of the IJHF band, and channel 9 of the Japan channel has its second high frequency and the beat interference of the U) IF band. There is beat interference with channel 30.

Therefore, it has been desired to propose a method for eliminating such beat disturbances.

Therefore, the present invention has been proposed in view of the above, and the U
An object of the present invention is to provide an improved structure of a signal input circuit that eliminates interference from the IF side.

That is, the present invention relates to a turret type tuner suitable for eliminating beat interference of UHF signals to a specific channel of the VHF band, and an object of the present invention is to provide an improved circuit arrangement of the VHF band tuning segment and the fixed side terminal that constitute the turret body. .

According to the present invention, the turret tuner has a UI disposed around a holding means including a metal holding plate fixed to a tuning shaft.
Consisting of a turret body having an F relay segment and a VHF tuning segment, and a wiring body of a fixed side tuner component to which one segment selected here is electrically coupled via a terminal of a fixed contact group. and form a tuner circuit for the desired channel.

A metal retaining plate supports the input stage of each segment and is electrically connected to ground.

In addition, a predetermined VHF channel tuning segment has a contact body attached to the input stage at a position that contacts the UIF input Kataka terminal among the fixed contacts, and this contact body is electrically connected to the grounded metal holding plate. Ru.

Therefore, when this predetermined channel tuning segment is selected, the UIF input Kataka terminal of the fixed contact group becomes grounded, and as a result, the LJHF input from the UHF tuner side
The signal is directly grounded to eliminate beat interference when receiving a given channel.

The input circuit of the present invention is extremely practical in that countermeasures can be taken only for specific channels where beat disturbance is likely to occur, for example, the Japanese channel 9 channel.

For example, traditional channel-specific tuning segments are
Normally, a contact body that comes into contact with the F-type Kataka terminal is not attached, but the input circuit of the present invention can be constructed by attaching a contact body and having a part of it come into elastic contact with a metal holding plate.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a side view of the turret-type tuner according to the present invention, with the shield cover removed, and FIG. 2 is an electrical wiring diagram of the tuner of FIG. 1.

This tuner consists of a chassis base 1 and a front plate 2.
The turret body 4 is configured to be rotatable so that a channel can be selected within the space between the turret body 4 and the back plate 3.

The turret body 4 includes three VHFHF-low channel tuning segments 5, one tJHF band chaff channel relay segment, six VHF band bi-channel tuning segments 7, installed on the tuning shaft 8 using a holding means. configured.

A fine tuning mechanism for finely tuning each local oscillation frequency of the VHF band channel tuning segments 5 and 7 is arranged in front of the front plate 2 of the tuning shaft 8, and a turret type VHF tuner with a preset fine tuning method is configured. .

The turret body 4 is rotated by the tuning shaft 8 to select a desired channel segment, and the selected segment is connected to the fixed side wiring body 10 formed inside the chassis base 1 on the stator bar 11. They are electrically coupled via fixed contact group terminals to form a tuner circuit for the desired channel.

The fixed side wiring body 10 has a circuit configuration shown in FIG. 2, and a local oscillation stage 12 including a tuning coil 13 is formed at the inside front of the chassis base 1.

At the center of the chassis base 1, a mixing plate 14 is connected to the tuning coil 1.
5, and an RF amplification stage 16 including a signal input circuit according to the present invention is arranged at the inner rear part.

The input signal of the tuner is the VHF input terminal 17 of the phono jack provided on the deck part of the chassis base 1 and the UHF input signal.
It is supplied from the IF input terminal 18, and reception switching between the VHF band and the U)IF band is performed by switching the input stage in each segment.

On the other hand, the output from the tuner is derived as an intermediate frequency output signal from the positive output terminal 19 of a phono jack attached to the chassis base.

Furthermore, for the operation of the tuner circuit, the RF amplification stage 16 has an A
An AQC signal is supplied from the GC terminal 20, and the local oscillation stage 1
2 is supplied with an AFT signal from an AFT terminal 21.

Further, in addition to supplying operating current for the tuner circuit from a power supply terminal 22, a UHF power supply terminal 23 is provided for driving a UHF tuner (not shown).

Reference numeral 24 is a test point of the tuner, which is used for adjustment and repair.

In the above-mentioned turret type tuner circuit arrangement, the input stage portion of the VHF and IJHF band reception signals according to the present invention includes a UIF input terminal 25, a trap terminal 26, an RF amplification element terminal 27, and a fixed contact group of the stator bar 11. It has a VHF input terminal 28, and the reception band of UHF or VHF band is switched through these terminals.

That is, depending on whether the input tuning coil 29 of the relay segment 6 is connected to the terminals 25 and 27 or the input tuning coil 30 of the tuning segment 5 or 7 is connected to the terminals 26, 27 and 28, the reception of the UHF'' channel and the VHF channel can be controlled. A band is selected.

Here, the additional contact body 31, which is a feature of the present invention, is VHFHF.
Provided in the high channel tuning segment 7 for a specific channel of the middle channel, for example, channel 9, and the UI
It is arranged at a position opposite to the F input terminal 25.

This contact body 31 is electrically grounded through a metal holding plate 32 provided at a position of the holding means constituting the turret body 4 to hold the input step portion of the segment.

That is, the holding means for the turret body 4 includes, as shown in FIG. 3 of the metal holding plate 32 mentioned above
It is formed of two metal retaining plates 32.
．． 34 are each in a grounded state.

In other words, the shielding metal holding plate 34 is always in contact with the ground terminal 35 of the stator bar 11 and is electrically grounded, whereas the metal holding plate 32 on the segment end side is connected to the metal tuning shaft 8. It is electrically connected to the shielding metal holding plate 34 through the shielding metal holding plate 34 to obtain a grounded state.

In the above configuration, the contact body 31 attached to a particular channel tuning segment 7 is grounded by bringing the extended portion of the contact body 31 into elastic contact with the metal holding plate 32, as shown in FIG.

Therefore, when this specific channel tuning segment 7 in the VHF band is selected, the UIF input terminal 25 of the stator bar 11 is grounded.

As a result, the UHF signal coming from the tJHF tuner (not shown) is directly grounded when receiving the aforementioned specific channel in the VHF band, and does not cause beat disturbance.

The present invention is extremely practical as it can be achieved by simply adding a grounded contact body 31 to the conventional tuner configuration.
Provides a structure for eliminating signal interference.

In the specific example of the present invention, a structure was described in which two metal holding plates were used as the holding means for the turret body, but similar grounding could be achieved by using only the metal holding plate for the interstage shield between the RF amplification stage and the mixing stage. Of course, it is possible to do so.

In this case, in addition to providing the contact body near the metal holding plate for the UIF human Kataka terminal mold and bringing the contact body into direct contact, a suitable body may be interposed.

Furthermore, if the metal holding plate at the end is omitted and the turret body is constructed with two holding plates, the tuner can be simplified and a small and inexpensive turret type tuner can be provided, which has great industrial value.

[Brief explanation of the drawing]

Fig. 1 is a side view of the turret-type tuner according to the present invention excluding the shield cover, Fig. 2 is an electric circuit diagram of the tuner shown in Fig. 1, and Fig. 3 is an exploded perspective view of the main part of the turret body shown in Fig. 1. , and FIG. 4 are sectional views of essential parts of the turret body of FIG. 1. 4...Turret body, 5,7...VH
Tuning segment for FHF transmission and reception...UHFHF
Segment for borrowing... Channel selection axis, 10...
...Fixed side wiring body, 16...Input RF amplification stage,
25...Kataka terminal 1 with UIF...
...Contact body (addition), 23.34...Metal holding plate.

Claims (1)

[Scope of utility model registration request] A relay segment for UHF band reception and a plurality of tuning segments for VHF band reception are attached to the periphery of a holding means fixed to the tuning shaft to form a rotatable turret body, and this turret body can be selected. In a tuner that connects one segment to a fixed side wiring body through a terminal of a fixed contact group to control a tuner circuit of a desired channel, the holding means is an electric conductor that supports an input RF amplification stage portion of each segment. The tuning segment of the predetermined channel is provided with a contact body at a position corresponding to the UIF input terminal of the fixed contact group in the manual RF amplification stage portion of the tuning segment of the predetermined channel. When electrically connected to the metal holding plate and receiving a predetermined channel of the VHF band, a UIF input terminal is installed.
A turret-type tuner characterized by eliminating interference caused by IF signals.