JPS59228706A - Manufacture of high frequency transformer - Google Patents

Abstract

PURPOSE:To improve the balance of inductance and capacitance of a primary coil and a secondary coil by a method wherein a pair of wires are twisted together to make one line to form the primary coil and one wire is wound to the direction opposite to that of the primary coil to form the secondary coil. CONSTITUTION:A parallel wire W4, which is composed of a pair of wires W1 and W4 which are insulated and closely laid in parallel, is wound around a core center 14' without twisting. Two lead parts of the parallel wire 4, which are drawn out of a core 14, are separated into two wires. A lead part W1' of one wire W1 of one end and a lead part W2' of another wire W2 of another end are twisted in front of the core center 14' to form a one line center tap 17. After the core 14 is turned 180 deg. upside down, one wire W3 is wound around the core center 14' from the back end 14d of the core to the direction opposite to that of the parallel wire W4. As a result, the secondary coil 16 is formed by winding the wire W3 around the core center 14' to the direction opposite to that of the primary coil 15 so that the balance of inductance and capacitance of the primary coil 15 and the secondary coil 16 is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application This invention relates to a method for manufacturing a high frequency transformer used in a double balanced mixer circuit of a CATV (cable television) converter.

In the prior art, an up/down type CATV converter is used when CATV broadcasting is received by a Tsutomi television receiver. This method receives broadcast signals over a wide band and divides them into two
In this method, the frequency is converted twice through two frequency conversion circuits to convert the signal into a predetermined empty channel signal of the television receiver.
A conversion operation is performed to obtain an HF band output, and a subsequent conversion circuit lowers the frequency of the UHF output to obtain a predetermined channel output.

For example, an example of a converter circuit for CATV using the above method is shown in FIG. 1. (1) is an input circuit consisting of a low-pass filter provided to pass broadcast radio waves of 54 MH2 to 440 MH2 to which cable television broadcasting channels are assigned. , (2) is the input tuning voltage (T
668MHz ~ 105105O(7) depending on U)
A first local oscillation circuit that outputs oscillation, (3) a first amplifier that amplifies the oscillation output of the first local oscillation circuit, and (4) a first amplifier that amplifies the oscillation output of the first local oscillation circuit. )
(5) is a double balanced mixer circuit that mixes with the local oscillation output input from the amplifier to generate the first conversion output; (5) is a P circuit that divides the output of the amplifier (3) into 1/256 or 1/64
This is a prescaler for the LL circuit and is the first AFT control circuit.

(6) is the output 6 of the double balanced mixer circuit (4).
12.75M A first band pass filter that selectively passes the first conversion output of H7, (7) is a conversion amplifier that amplifies the output of the first band pass filter (6), (8
) is 612.75 MHz from the output of this amplifier (7).
a second section provided to selectively pass the converted output of the
(9) is a second local oscillation circuit for the CATV converter to convert to a predetermined channel of wireless television broadcasting, (10) is the output of the second band pass filter (8) and a double balance mixer circuit. A mixer circuit mixes the output of (4) and (11) a mixer circuit (
a third bandpass filter that selectively passes the converted IF small output to a predetermined channel outputted by (10);
2) is an IF output terminal that outputs the IF output of the third bandpass filter (11) to the outside, and (13) is an output circuit (1).
This is a second AFT control circuit that extracts the IF multiplied signal of 2), detects a deviation from a predetermined frequency, generates an AFT voltage, and sends it to the AFT circuit in the second local oscillation circuit (9).

By the way, in the double balance mixer circuit (4) in the above converter, one transformer T of a high frequency transformer for a double balance mixer is used on the output side of a bridge circuit consisting of four diodes D, D, . This transformer T has a primary coil and a secondary coil wound around a core, and what is required of this coil is that the coil be wound so that the inductance and capacity of the primary and primary sides are equally balanced. It is. The best coil winding form that satisfies this requirement is to wind both the primary and secondary coils completely symmetrically around the core, but this is idealistic and cannot be realized. Therefore, various measures have been taken to more fully satisfy the above requirements, and one effective one is, for example, one in which two twisted wires are wound around a core as a primary coil. However, it is difficult to twist two wires unevenly (twisting), and despite the complicated wire twisting work, it is not very effective at present, and improvements have been desired.

C.9 Purpose of the Invention It is an object of the present invention to provide a high frequency transformer that meets the above-mentioned needs.

21 Structure of the Invention The present invention is characterized in that two parallel wires are integrated in the central part of a spectacle-shaped core without twisting (winding them, and separating both lead-out portions of the parallel wires led out in the same direction). Twisting the different wires one by one into a single line to form a primary coil, and twisting the primary coil into the center of the core where the secondary coil is wound upside down from the direction opposite to the primary coil. It is characterized by forming a secondary coil by winding one wire in the opposite direction.By winding the coil in this manner, the coil winding work becomes easy, and the secondary coil is The balance between the inductance and capacitance of the coil becomes better.

E. In the embodiments shown in FIGS. 2 to 4, (14) is a spectacle-shaped ferrite core, and (14a) and (14b) are cores (14).
Both sides of (14c) (14d) are the core (14
) shows the front and rear end surfaces. (15) and (16) are the core (1
The primary coil and the secondary coil are wound and attached to the central part (14') of the 4) from opposite directions, respectively.
5) is provided with a center tap (17) as shown in FIG. -The next coil (2) has a total of two wires W1,
From W2, a secondary coil (16) is formed from one wire W3 in the manner shown in FIGS. 6 to 10 below.

First, as shown in Fig. 6, a parallel wire W4, in which two wires W1 and W2 are insulated and integrated in parallel, is prepared, and this is wired from the front end face (1c) of the core to the center part (14'') of the core without twisting. They are wound in parallel, for example, two turns without slack, and both ends are led out toward the front end surface (14c) of the core.

Next, as shown in FIG. 7, both ends of the parallel wire W4 from the core (14) are separated into two wires. Then the 8th
As shown in the figure, one derived portion W' of one wire W1
Twist the lead-out portion W'2 of the other wire W2, which is different from the one described above, from the front of the central part of the core (14") and electrically connect with solder or the like to make one wire, and make a center tap (17). It is also possible to electrically insulate the remaining lead-out portions of each wire Wl and W2 and twist them together, but if this is done, the wire lead-out portions W'' that were twisted first
1. W"2 may become loose, which is not preferable.

Next, move the core (14) up and down 180 degrees as shown in Figure 9.
After inversion, one wire W3 is wound from the rear end surface (14d) of the core in the same direction as the winding direction of the parallel wire W4. In other words, as a result, the wire W3 is wound in the opposite direction to the parallel wire W4 around the central part of the core (14"), forming a secondary coil (16) and achieving a balance between inductance and capacitance with the primary film (15). Sexuality improves.

As described in detail in Section 8, according to the present invention, the work of winding the secondary coil is particularly facilitated by the use of parallel wires, and the inductance and capacitance between the secondary and secondary coils are well balanced. Coil winding work is now possible, and a high-frequency transformer for double-balanced mixers with stable characteristics and high performance can be provided.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram using a high frequency transformer for a double balance mixer, Figures 2 to 4 are front and left and right side views showing an embodiment of the present invention, and Figure 5 is the transformer shown in Figure 2. 6 to 10 are perspective views at each stage of the manufacturing process of the transformer shown in FIG. 2. (14) - core, (14') - central part of core, (15
) - 11 primary coil, (16) - secondary coil, Wl
, W2, W3, - wire, W4--parallel wire.

Claims (1)

[Claims] (1) The process of winding a parallel wire in which the two parallel conductors of the primary coil are insulated in the center of the spectacle-shaped core, and leading out both ends of the wire in the same direction, and keeping both leading parts of the parallel wire in an insulated state. and twisting each one of the different lead-out portions to each other, and winding one conductor of the secondary coil upside down in the center of the core from the opposite direction to the winding of the secondary coil. A method for manufacturing a high frequency transformer, including a step of winding insulated wire.