JPS5813014A - Tuning circuit - Google Patents

Abstract

PURPOSE:To freely adjust the electrostatic value of a varactor diode and its variable magnification, to improve tuning characteristics, and to obtain an effect to tracking adjustment, by optionally varying the voltage characteristics of a power source for applying a voltage to the varactor diode. CONSTITUTION:A variable inductance 1 and a varactor diode 2 are connected in parallel, and the diode 2 is supplied with the output of a power source circuit 8, composed of variable voltage circuits 5 and 6 and a variable resistor 7 after the adjustment of a variable adjusting circuit 9. The circuits 5 and 6 couple with the variable inductance 1 to vary the tuning frequency of a tuning circuit. When the movable contact of a variable resistor R7 is moved toward the side of the circuit 5 or 6, the upper limit and lower limit of the capacity value of the diode 2 are adjusted easily, its variable magnification is set easily, and tracking adjustment is facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present application relates to a tuning circuit that selects a tuning frequency by varying L and C, and in particular uses a variable capacitance diode as C, and allows the voltage characteristics of the power supply applied to the variable capacitance diode to be arbitrarily adjusted. The purpose of this invention is to provide a tuning circuit which enables free adjustment of the capacitance value and its variable multiplier, has excellent tuning characteristics, and is effective for tracking adjustment.

Generally, the main reason why L variable tuners made of variable inductance elements η) are widely used in car radios and the like is that they have extremely good strong input characteristics, and they can withstand external vibrations, large changes in temperature and humidity, or Effects of dust etc.
Therefore, this is advantageous compared to a C variable tuner in that the reception characteristics do not change or the operation becomes unstable, and products can be easily made uniform. However, the problem with variable inductance tuners is that it is extremely difficult to precisely adjust the tracking between the tuned circuits, and the gain decreases at higher frequencies, while the gain decreases at lower frequencies. Since this becomes abnormally high, the operation of the receiver becomes unstable, and it is impossible to improve the performance of the receiver by increasing the number of tuning circuits.

That is, as is well known, the variable inductance tuner is equipped with a variable inductance element for each tuning circuit of the glue antenna circuit, RF circuit, and O8C circuit, and each variable inductance element is manually operated by the same sliding member. This method achieves tuning by varying the L of each tuning circuit, but due to errors in side effects, the frequency characteristic curves of each variable inductance element differ, and conventionally this method The difference in the frequency' characteristic curve can be adjusted by adjusting the position of the origin of the high-frequency magnetism 9a relative to the coil body.
Alternatively, mutual tracking adjustment between the tuning circuits has been performed by exchanging high frequency magnetic cores with different μ. However, in the former case, even if the position of the protruding and retracting base point is adjusted, the frequency characteristic curve of the variable inductance element only shifts in parallel. Even if the characteristic curve is tuned to a certain point, the frequency curve will not match for the frequencies before and after that point.Therefore, even if the position of the protrusion and retraction base point of the high frequency magnetic core with respect to the coil body is adjusted, the frequency characteristic curve between the tuned circuits will not match. are only close to each other, and the variable stroke of the variable inductance element is determined by the mechanical sliding stroke of the sliding member in the tuner. The upper and lower limit positions of the tuning frequency obtained when the position is adjusted change over time, so it is extremely difficult to perform accurate tracking adjustment only by adjusting the position of the protrusion/retraction base of the magnetic core with respect to the coil body.

In the latter case, the work of measuring and classifying the μ characteristics of the high frequency core into numerous ranks and exchanging them is extremely troublesome and greatly lacks workability. Furthermore, the variable inductance tuner has the disadvantage that the gain decreases at higher frequencies, making it impossible to obtain a stable and uniform gain over the entire tuning frequency band.

Therefore, in the present application, the above-mentioned defects can be improved by varying L and C, which set the tuning frequency, in an interlocking relationship, and making it possible to adjust the capacitance value of C and its variable magnification. If I'm being honest about this, (1) is a variable inductance element, and a variable capacitance diode (2) is connected to it.
) are connected parallel to each other via a fixed capacitor. (4
) is a temperature-maintaining capacitor, (51 and (6: variable inductance element 11) are variable voltage circuits that are variable in conjunction with each other, and each has variable resistors - and - with different variable resistance characteristics. , this variable voltage circuit (51 and (6
) has a semi-fixed variable resistor technique and the previous variable resistance circuit (7)
This variable voltage circuit (51
and (61) and the variable resistance circuit (7) constitute a power supply circuit (8) for the variable capacitance diode (21). (9) constitutes the power supply circuit (8) for the variable capacitance diode (21) The previous variable capacitance diode (2
This variable adjustment circuit (9) is a variable adjustment circuit that adjusts the operating range of No. 1, and this variable adjustment circuit (9) includes a semi-fixed variable resistor R4m connected to a 10B power supply, a movable contact of this variable resistor R95L, and the variable resistor It consists of a semi-fixed variable resistor -R41b which is RIG-connected to the movable contact of 81, and this variable resistor 1fI
The movable contacts &b are connected to a variable capacitance diode (21). RIG is a protective resistor.

In the above, as the variable voltage circuit (5) and the flag 1 constituting the power supply circuit (8), for example,
As shown in Publication No. 064, there is an oscillator that oscillates at a constant frequency, a transformer that varies the output voltage by applying magnetism to a transformer coil to which this oscillation frequency is applied, and an output voltage of the transformer. Of course, it is also advisable to use a variable voltage circuit consisting of an am corner rectifier circuit.

If the first limit of the bandwidth of the tuning frequency is fmla and its upper limit is fm*x, then the resonant frequency f is expressed as
51 d/, tax wz
a * * m * a @2πJ door height 5] Blind i However, Ixin is the minimum value of variable inductance 'Lm*x is the maximum value of variable inductance Cm1 m is the minimum capacitance value of the variable capacitance diode Cmax is the maximum capacitance value of the variable capacitance diode 1, and the relationship between the variable magnification of L and C and the tuning frequency is expressed as . .

Now fmim is 51k) kHz, fm*x is 165
0KH2.

For example, all of this AM band, such as L variable O and 2
Therefore, if t is covered, the variable magnification of L is 10.47.

From the formula, assuming that the current variable magnification is set to, for example, 7, X, that is, frrmx, becomes 1349 KH2, which is the 1AM band width f) 1349KH2 to 16! $
Since there is a lack of selection of tuning frequencies in the range of 0KH2, an attempt is made to compensate for this shortfall in bandwidth with the variable magnification of C. From the formula, X, that is, the variable magnification of C, is determined to be approximately 1.
It becomes 5.

Therefore, the variable magnification of the variable capacitance diode in the tuning circuit is 1.
By setting it to 5, the variable magnification of L can cover the required band width at 7. This relationship is illustrated in Jl! It will look like Figure 2. That is, Fl is the tuning frequency characteristic curve obtained when the magnetic core protrusion and retraction stroke is, for example, 10 degrees in a variable inductance element in which a high frequency magnetic core protrudes and retracts from the coil body, and F2 is the protrusion and retraction stroke of the magnetic core. For example, 8■,
This shows the tuned station wave number characteristic curve when the insufficient band width is supplemented by the variable magnification of C.
It is understood that the required Q-band width can be obtained by electrifying the slope of characteristic-11AF1 by using only the variable multiplier and shortening the magnetic core's protrusion and retraction.

However, in general, when the variable magnification of L shows a value around 7 due to manufacturing errors, or when there is variation in the variable range of the variable capacitance diode used, as a correction in such a case, if When the variable inductance element is composed of a coil body and a high-frequency magnetic core that moves in and out of the coil body, and the base position of the high-frequency magnetic core in and out of the coil body can be adjusted, the coil of the high-frequency magnetic core By adjusting the appearance base position relative to the body,
As already mentioned above, the characteristic curve of the tuning frequency moves in parallel, so even when the base point position of the tuning frequency characteristic curve is truly 500KH2 or 520KH2, the mode of the characteristic curve does not change. It can be adjusted to 510 by 1 (Z#c).

However, as shown in FIG. 3, for example, a saturation magnetic circuit consisting of a pair of magnetic conductive plates a and ζ and a coil a21 wound in the sandwiching direction is connected to two high-frequency magnetic cores αJ and the magnetized side! The magnet a9 held between the pair of magnetically conductive plates a41ζ is arranged close to each other so that the side edges of the pair of magnetically conductive plates aυ and a- face each other, and they are placed relative to each other along the opposing surfaces. The magnet ■ or the magnetic core a3 is moved so as to vary the dispersion of the magnetic flux passing through the saturation magnetic circuit, and at the final position where the facing surface is removed by moving η), the magnet ■ or the magnetic core a3
For example, the Japanese Patent Publication No. 51, comprising a short-circuiting piece a.
-32380 Variable inductance element shown in the current publication or Japanese Patent Publication No. 1849-3274, Japanese Patent Publication No. 51-32381
As shown in the above publication, in the case of a structure without an error adjustment mechanism such as the lζ variable inductance element, the base point position of the tuning frequency characteristic curve cannot be corrected.
This has the disadvantage that it is extremely difficult to perform tuning adjustment (matching between the tuning circuits).

Therefore, the present application proposes an Imaoka track with variable L and C, which has an error adjustment mechanism as described above and can be effectively applied even when variable inductance is performed using a non-variable inductance element. , In more detail, by using the fact that the I\I characteristic line of the applied voltage versus capacitance of the capacitance diode is quadratic-1, the capacitance value play obtained by the variable capacitance diode ( By adjusting the variable multiplier arbitrarily, the required band width of the tuning frequency III characteristic and its base position can be accommodated; Moreover, it provides a tuning circuit that is effective for tracking adjustment.

The effects of the present application will be described in detail below. First, to explain the power supply circuit (8), this time we will explain the variable inductance element (1) of the variable voltage circuit (5) and (6).
The voltage characteristic-line obtained in conjunction with is Es in Figure 4.

When it is assumed that the movable contact of the variable resistor R1 is located in the center position, the voltage characteristic -aIEII of the power supply circuit (8) indicates the characteristic in the middle of the voltage characteristic curve. , and in this state, variable resistor R7
When the movable contact is moved to the variable voltage circuit (5), the voltage characteristic curve E8 of the power supply circuit (8) approaches the voltage characteristic -4IEs, and the movable contact is moved to the variable voltage circuit (5).
When this movement is made, the voltage characteristic -@Va of the power supply circuit (8) approaches the voltage characteristic -@Es, and therefore the voltage characteristic 1M1IIIE8 of the power supply circuit (8) is changed to two variable voltage circuits (5) and 1M1IIIE8 by variable resistor R7. (8) The voltage characteristic can be arbitrarily varied between white lines M and M.

Next, the action lζ of the variable adjustment circuit (9) will be explained.
The current 10B power supply is 10V, and the power supply circuit (81O
It is assumed that the voltage characteristic 11F4 changes from Ov to tovt in conjunction with the variable inductance element (1), and the movable contact of one variable resistor 5R11b of the variable adjustment circuit r91 is adjusted to its center position E. In this state, if the movable contact of the other variable resistor Raa is set to the highest potential point A, the -ζ power supply circuit (when it is at the 81% highest potential tOV, the variable resistor II Rob
Since the potential across the terminal is IOV, IOV is applied to the variable capacitance diode (21), and then the calculation circuit (8)
When reaches the lowest potential ov, the potential difference across the variable resistor - becomes 10V, and 5V of that k is applied to the variable capacitance diode (2) (hereinafter referred to as the first example). When adjusting the movable contact of the variable resistor Rsa to the intermediate value C, when the power supply circuit (81) is at the highest potential of 1 ov, one end of the variable resistor R9b should be 5V and the other end should be 1°V. Therefore, the variable capacitance diode (2) is connected to the power supply circuit (with the intermediate potential of 7.5Vdjt).
8) reaches the lowest potential Ov, since one end of the variable resistor -b is 5V and its aIIilII is Ov, the variable capacitance diode (2) is applied to the intermediate potential 2.
5V is applied to each (hereinafter referred to as 2 examples), and in the circuit state described above, when adjusting the variable resistor R@aO movable contact to its lowest voltage position, the power supply circuit (81 is at the highest potential of 10V) When one end of variable resistor R4b is ov
Since the other voltage is 10V, the variable capacitance diode (2) has an intermediate potential of 5V, and the power supply circuit (8
) reaches the lowest potential Ov, both ends of the variable resistor - are Ov and Ov is applied to the variable capacitance diode (21 (hereinafter referred to as the third example)).

That is, from the above-mentioned examples 1 to 3, when the variable resistor S- is adjusted by eliminating the variable resistor S-, the variable capacitance diode (
2) In the first example, the voltage applied to 10V to 5VI
C1 7.5V-L5V in the second example, 5v ~ in the third example
0■, the variable potential difference is constant at 5V, and Iζ
, the operating reference voltage for the variable capacitance diode (2) is lOV% at the upper limit? .

5v, 5v, M9 lower limit C gate is 5v, 2.5v, O
It is understood that each of these conditions is regulated by v.

Next, the movable contact of one variable resistor R11b of the variable adjustment circuit (91) is adjusted to the intermediate point C, and in this state, the movable contact of the other variable resistor R11b is adjusted to the lower position, the intermediate point E, and the upper position. A case will be considered in which the power supply circuit r81 is linked with the variable inductance element (1) and varied from tloV to Ov.First, the variable resistor R4I
When the movable contact b is located at the lower point 2 and the power supply circuit 1B) is at the highest potential of 10V in this state, the variable resistor 11R
The movable contact of eb is directly connected to the midpoint of variable resistor R9m!
Since this will result in a red ribbon, please use a variable capacitance diode (21
A voltage of 5V is applied to this! The voltage of sv remains constant regardless of voltage changes in the power supply circuit (8) (hereinafter referred to as the fourth example). In addition, when the voltage of the variable resistor &b is adjusted to the midpoint E, the power supply circuit (when the voltage of β1 is varied, the voltage is applied to the variable capacitance diode The voltage is changed to 7.5V-5V (1, and the movable contact of variable resistor R4b is adjusted to 1' at the upper point of that □,
In this state, the 'power supply' circuit (8,. tlEd, 1° is shown. v, cw change, d is a.

□ Directly connect the movable contact of variable resistor Re& to the movable contact of variable resistor R7! Since it is connected, the variable capacitance diode (21 [The applied voltage changes toy-ov equal to the variable voltage range of the power supply circuit (8), hereinafter referred to as the fifth example). That is, as is clear from the above-mentioned fourth example, fang 2 example, and fang 5 example, one variable resistor Rab of the variable adjustment circuit +61 is adjusted while keeping the other variable resistor Rk constant, and in this state, the power supply circuit ( When the voltage of the variable capacitance diode (21) is varied, the voltage applied to the variable capacitance diode (21) is constant at '5v in the fourth example, regardless of the variation, and in the second example, the voltage applied to the variable capacitance diode (21) is 7.5V.
Changes from v to 5v, 3! In p5 cases, it changes from 10v to Ov. In other words, it is understood that the operating range of the variable capacitance diode (2) can be adjusted by adjusting one of the variable resistors S to b of the variable adjustment circuit (91).
The connection between the variable capacitance diode (2) and the power supply circuit (8) helps to adjust the operating range of the variable capacitance diode (2) and the power supply circuit (8).When connecting the variable adjustment circuit (9), there are advantages as described below. has. That is, generally a variable capacitance diode (2)
Since the O capacitance characteristic is represented by a secondary line as shown in Fig. 5, the variable capacitance diode (
Even if the variable width applied to 21 is constant, va"'va
It is possible to make the capacitance value and variable magnification obtained at the time of death and the time of death true, and it is also possible to change the variable width and use, for example, the characteristics of vb, ..., vc. It has the advantage of being able to

The fourth cabinet connects two variable capacitance diodes (21, (2)' in parallel to the variable inductance element (1), and
Variable voltage circuit +5L (61 is common, this variable voltage circuit +5), (6tK respectively variable resistance circuit (71, (
Connect both ends of 71' and connect variable resistors (9) and (p)' between each variable resistor (71' and each variable capacitance diode (2) and (21'), respectively). Another embodiment is shown in which two variable quantity diodes Ll) and 4! are connected according to !0111m.
The C of the tuned circuit is determined by the composite capacitance of j', and
The setting of the combined capacitance value of the heron is done by selecting sets i and j of each variable adjustment circuit.
Since it is carried out in this manner, it has the advantage that more detailed electrostatic quantity values and their variable magnifications can be determined.

As described above, according to the present application, any range of the capacitance characteristic curve of the variable capacitance diode can be selected by adjusting the variable adjustment circuit, and the power supply applied to the variable capacitance diode via the variable adjustment circuit can be selected. Since the voltage characteristics of the circuit can also be changed arbitrarily, the upper and lower limit positions of the capacitance value of C that make up the tuned circuit can be adjusted and the variable magnification can be set extremely precisely. This is effective for correcting production errors or parasitic effects in elements such as variable capacitance diodes. Therefore, it is possible to provide a nine-tuned n-path with excellent tuning characteristics and strong input characteristics. When the tuning circuit is used to configure the channel selection device, it has the advantage that tracking adjustment can be performed at 4m1JI.

[Brief explanation of drawings]

The drawings show an embodiment of the present application, and FIG. 1 is a tuning circuit diagram, FIG. 2 is a diagram showing tuning frequency characteristics, FIG. 3 is a configuration diagram of a variable inductor element, and FIG. 4 is a voltage characteristic curve. FIG. 5 is a diagram showing the capacitance characteristics of a variable capacitance diode. FIG. 6 is a diagram showing another embodiment of the tuning circuit. In the figure, (1) is a variable inductance element, (2), (2
+' is a variable capacitance diode, +51 and +61 are variable voltage circuits, (7). (7)' is a variable resistance circuit, (8) is a power supply circuit, 191
, 191' is a variable adjustment circuit, Rs, R6, R7, R
;, R9m@Robe R;a and Rs'b are variable resistors. , Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] (1) A variable adjustment circuit that variably adjusts the operating range of the variable capacitance diode is connected between the variable capacitance diode connected in parallel to the variable inductance element and the power supply circuit,
The power supply circuit includes two variable voltage circuits that operate in conjunction with a variable inductance element and have different variable voltage characteristics, and a variable resistor that is bridge-connected between the two variable voltage circuits and has a movable contact connected to the variable adjustment circuit. 1. A tuning circuit comprising: a variable resistance circuit having a variable resistance circuit; (2) The variable adjustment circuit is Iζ bridge-connected between the first variable resistor and the variable resistor of the power supply circuit, and its movable contact is connected to the variable capacitance diode Il! A tuning circuit according to claim 1, comprising a second variable resistor and a first variable resistor connected to the B power source. (3) The two variable voltage circuits are each connected to the B power source. Claim i! The 1st term meeting for 1 year old is the tuned circuit described in 2nd term. (4) At least two variable capacitance diodes are connected in parallel to the variable inductance element, and a variable adjustment circuit is provided between each variable capacitance diode and the power supply circuit to variably adjust the operating range of the variable capacitance diode. Two variable voltage circuits with different variable voltage characteristics are connected to each other, and the front distribution power supply circuit is linked to the variable inductance element. Bridge connections are made between these two variable voltage circuits, and the movable contacts are connected to each of the variable inductance elements. A tuning circuit whose characteristic is that it consists of two variable resistance circuits each having a variable resistor connected to the circuit. (51 variable adjustment path consists of a first variable resistor and a second variable resistor that is bridge-connected between the variable resistor of the power supply circuit and whose movable contact is connected to the variable capacitance diode,
The first variable resistor is connected to the source B[9].
Tuned circuit described in section. (Claims 4 and 9 of the patent claim, in which the two variable voltage circuits each include a variable resistor connected to the B power supply, are the tuning circuits described in claim 5. (7) For the two variable capacitance diodes, Power supply circuit 2
A tuning circuit according to claim 4, claim 5, or claim 6, which comprises two variable voltage circuits in common.