JPS6336618A - Multi-band tuner - Google Patents

Abstract

PURPOSE:To reduce number of components of the circuit and to contrive to attain miniaturization by using the circuit being a part of the titled tuner in common for VHF and UHF bands. CONSTITUTION:At the reception of the VHF band, a signal coming to a terminal 2 is subject to filtering of VHF band signal only by an input filter 16, the result is selected and tuned by a VHF single tuning circuit 17, amplified (19), a prescribed selectivity characteristic is given by a VHF double tuning circuit 20, given to a mixer circuit 23 and an IF output signal is outputted to a terminal 14. At the reception of UHF band, the signal incoming to the terminal 1 is fed to a UHF single tuning circuit 18, where the signal is tuned and amplified to a prescribed level, the result is a UHF double tuning circuit 21, where a prescribed selectivity characteristic is given, the result is fed to the mixer circuit 23 and outputted to the terminal 14 as the IF signal. Since the varactor element is used in common for the UHF, VHF bands in the input tuning circuits 17, 18, inter-stage tuning circuits 20, 21 and an oscillator 22 in this way, number of components is reduced and the tuner itself is miniaturized.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention relates to a multi-band tuner, and in particular to a multi-band tuner in which variable capacitance elements and transistors used in a tuning circuit and an amplification/oscillation circuit are shared in different bands. Regarding band tuner.

<Summary of the Invention> The present invention is a superheterodyne multi-band tuner that reduces the number of parts and reduces the size by δ4 by sharing a common part of the tuner circuit for the VHF band and the UL band. It's a good thing.

<Prior Art> FIG. 7 does not show a block diagram of a conventional superheterodyne tuner that receives the V1 band and UHF band. 1 and 2 indicate input terminals for the UIIF and \111F bands. 3
is an input tuning circuit, 4 is an RF amplification circuit (high frequency amplification circuit)
, 5 is a double-tuned circuit, 6 is an oscillator, and Y is a mixer circuit.
These circuits receive the υIIF band.

8 is an input filter circuit, 9 is an input tuning circuit, 10 is R
F amplification circuit, 11 double tuning circuit, 12 oscillator and 13
are mixer circuits that receive the VHF band.

14 is a 1F signal output terminal from the mixer circuit 13.

15 is a 1.17J converter circuit (simply referred to as a 1.V to 7J converter circuit) for the VHF band and VHF band.

When receiving a V liver band signal, the signal from the double tuning circuit 11 is mixed with the oscillator 12 (Tatsu frequency is mixed in the mixer circuit 13, the output is 58.75), and the IF multiplied signal of IH2 is sent from the terminal 14. Output.

On the other hand, when receiving the IJHF band, double tuning circuit 57'l
) and the oscillation frequency signal from the oscillator 6 are mixed in the mixer circuit 7, and the mixed output is an IF multiplied signal of 58.75 Hz). After the signal is set to 1, it is output to the terminal 14. The u-■ switching circuit 15 is turned on so as to supply the IF multiplied signal from the UIIF mixer 7 to the VHF mixer 13 only during reception.

<Problems to be Solved by the Invention> This conventional multi-band tuner uses separate dedicated circuits for the VHF band and IJHF band receiving circuits, so there is a problem that the number of circuit components is large. There is a problem that this leads to an increase in cost.

Another problem is that the tuner cannot be miniaturized.

The present invention aims to solve the various problems mentioned above.

<Means and operations for solving the problems> The multi-band tuner according to the present invention has a configuration in which a part of the circuit of the tuner is shared between the VHF band and the VHF band.

By sharing the circuit in this way, it was possible to reduce the number of circuit parts and downsize the circuit.

<Embodiment> FIG. 1 shows a circuit block diagram of a multi-band tuner according to an embodiment of the present invention. Components that are the same as those in FIG. 7 are given the same reference numerals, and their explanations will be omitted.

16 is an input filter, 17 is a V1 single-tuned circuit, 18 is a UIIF single-tuned circuit, and 19 is a VHF/F common (hereinafter simply referred to as U/V common) RF amplification circuit (high frequency amplification circuit).
, 20 is Vt (F double tuning circuit, 21 is double F demotuning circuit,
Reference numeral 22 denotes a U-v shared oscillator, and 23 represents a U-V shared mixer circuit, respectively.

C1 is a variable capacitor for tuning of the U-V common tuning circuits 17 and 18. C2 and C3 are the variable capacitors of the double-tuned circuits 20 and 21 (1/V common).We will explain when receiving the VHF band.The signal that enters terminal 2 is passed through the input filter, allowing only the VHF band signal to pass. , is selectively tuned to the frequency of a desired station by the VHF tuning circuit 17, amplified to a predetermined level by the RF amplification circuit 19, given a predetermined selectivity characteristic by the double tuning circuit 20, and supplied to the mixer circuit 23. Here, the frequency is converted with the frequency from the oscillator 22, and the frequency-converted IF output signal is output to the terminal 14.

Next, reception of the UHF signal will be explained. The signal that enters the terminal 1 is supplied to a single tuning circuit 18, selectively tuned to the frequency of a desired station, and then supplied to an RF double tuning circuit 21 via an RF amplification circuit 19 to obtain a predetermined selectivity characteristic. is given and supplied to the subsequent circuit.

The frequency is converted by the mixer circuit 23 in the same manner as described above, and the signal is outputted to the terminal 14 as a 1F signal.

In this way, the input tuning circuit 17.18 The interstage tuning circuit 20°2
1 and oscillator 22 (details of which will be described later), the variable capacitance ω element is shared by U and ①, so the number of parts can be reduced.
Furthermore, the tuner itself can be made smaller.

FIG. 2 shows a modification of the circuit block diagram of FIG. 1. 1st
Components that are the same as those in the figures are designated by the same reference numerals, and their explanations will be omitted.

The difference from FIG. 1 is that the VII is installed before the RF amplifier 19.
F and F double tuning circuits 24 and 25 are arranged, and RF
VHF and IJHF single tuning circuit 2 after one amplifier
This is the point where numbers 6 and 27 are placed.

Next, a specific circuit diagram of FIG. 1 is shown in FIG. 3.

The input filter 16 is composed of a low-pass filter (LPF) and a bypass filter (HPF), which are composed of coils Li, L2, and a capacitor C7, and passes the frequency of the \rllF band, and is connected to the next input single-tuned circuit 17.18. supplied to

Variable capacitance diode Dv1 and coil, VI at ~L6
It constitutes a single tuning circuit 17 for the IF band. In addition, IJ with inductor (common) wire line 8 and variable capacitance diode DV1
It constitutes a single-tuned circuit for the HF band.

Vl (Explain the operation when receiving F band.V11F
When receiving the VliF band, the switching diode D2 is necessarily off (non-conducting), and the inductance of the inductor (resonant line) L8 is negligibly small for the VliF band. First of all, the low band of the VHF band (1 to 3 inches
During reception (channel), no voltage is supplied from the terminal \Ill, the switching diode D1 is off, the tuning circuit is formed by coils 3 to L6 and the variable capacitance diode DV1, and the tuning frequency is supplied from the terminal VT. The desired channel frequency can be varied using the tuning voltage. On the other hand, during high band reception (channels 4 to 12), diode D1 is turned on (conducting state) by the switching voltage supplied from terminal VH, short-circuiting coils [4 and [5], and the tuning circuit is connected to coils L3. L6 and a variable capacitance diode DV1, and a desired channel (frequency) is tuned and selected by this capacitance diode DV1. These selected signals are supplied to the next stage RF amplification circuit 19 via the coupling capacitor C14.

Furthermore, during low band reception, capacitor C9.

Low band image with C10 and coils Ls and Ls (
208-220 old,) constitutes an eliminator for removal,
At the time of high band reception, capacitors C9 and C1o and coils L4 and 1-6 constitute an eliminator for blocking high hand images.

Next, the single tuning circuit 18 and its operation in the UHF band will be explained. When receiving IJIIF band, diode D2
Voltage is supplied from terminal U to diode D2, which turns on and becomes an inductor.One end is grounded with low impedance, and the variable capacitance diode DV1 is connected to the other end, forming a 174-person-shaped coaxial resonator. . Inductor. is an inductor for adjustment. The UIIF signal input from terminal 1 is inductively coupled from the coil [7 to the inductor [8], and selectively tuned to the frequency of the desired ψ channel by varying the capacitance of the variable capacitance diode DV1, and the signal is passed through the capacitor C14 to the FETI~ It is supplied to transistor Q1.

Since the inductor and the inductor are directly grounded with low impedance by the diode D2, the Q of the tuning circuit can be increased, the tuning output level can be increased, and a drop in the output level can be prevented, especially in the high frequency range.

Note that C8 and C11 are required as capacitors that require DC cut.

The input tuning circuit explained above connects the coils L3 to L6 and inductor L8 of the VL band and F band in series, and the variable capacitance diode DV1, and connects the connection point of the coil and inductor L8 to ground when receiving UHF band. Since the configuration is to connect diode D2 for
V1 can be shared by U and \l, which has the advantage of reducing the number of parts and the space required for assembly.

Next, the RF amplification circuit 19 will be explained. The output from the input single-tuned circuit 17.18 is supplied to the first gate G1 of the FE transistor Q1, and the second gate G2 is connected to the terminal AG.
AGC voltage is supplied from C. R1 and R2 are bias resistors, and D3 is a switching diode.

When receiving the vll [band, diode D3 is off,
In addition, the impedance of the coil '10 becomes small for the frequency band assigned to vl, but the bias resistors R1 and R2
has a high resistance, the impedance seen from the first gate G1 is high, and therefore the VHF signal is not attenuated and is
~ It is amplified by the transistor Q1 and is supplied from the drain D to the next-stage double-tuned circuit 20.21.

On the other hand, when receiving UHF band, connect terminal U only when receiving UIIF band.
Voltage is supplied from the diode D3, which turns on the diode D3. The F signal input in this state is amplified by Q1 and supplied to the double tuning circuit 20.21. When receiving U11E, the gain of transistor Q1 is small in the low range, and to correct this, impedance matching coil '10 is connected.

The input capacity of the first goo 1 to G1 is about 2PF. UH
When receiving F band, diode D3 turns on and coil '1
0 is grounded via capacitor C15, so the 61 power point of transistor Q is the input capacitance (2PF
) and the coil '10 form a parallel resonant circuit, the resonant frequency of which is set to 300)1117.

This increases the gain in the low F band, making the transistor gain uniform over the entire band.
Next, the double tuning circuits 20 and 21 will be explained. Coil, 1 to [15 and condenser"j C24, C26, C2
A parallel resonant circuit of 7Vt1) band is formed, an inductor is used, and the other is a coaxial resonator (resonant line). The capacitive diodes for variable tuning frequency of U・■ are Dv2 and Dv3.
is also used. C16, C17, C28 are grounding capacitors, 018 is a DC cut capacitor, C
Reference numeral 19 indicates coupling capacitors in the UHF band.

In such a circuit configuration, the circuit operation during VHF band reception will first be explained. During low band reception of the VHF band, the voltage from terminal V[ is diode 01
4. Resistor R3, coil '11. '12. '15 to the drain D of the transistor Q1. At this time, diode D8. D9 is off. Note that the voltage supplied to terminal 8 is always applied when receiving a signal. The diode 011 is also turned on by the power from the terminal Vt.

Diodes 01o and D13 are turned off. In this state, the primary side tuning circuit of the double tuning circuit is connected to the coil [
11, [12, [15, capacitor 026, and a variable capacitance diode DV2 connected in parallel to these.

In addition, the secondary side tuning circuit of the double tuning circuit has coils 13 to 13.
L15, capacitors C27 and C24, and a variable capacitance diode DV3 connected in parallel to these.

Incidentally, the inductance of the inductor connected in series with the variable capacitance diode DV3 is small and can be ignored with respect to the v range.

The tuning of this double-tuned circuit is performed by the variable capacitance diode DV2. This is done by varying the capacity of DV3.

Next, the high band reception of the VHF band will be explained. The voltage supplied from terminal VH is connected to diode D6 and resistor R.
4. It is supplied to D of the transistor Q1 via the diode Oat coil [11. At the same time diode 09,01
1 is on, and diodes 010 and '13 are off.

The primary side tuning circuit of the double tuning circuit is composed of a parallel circuit of a coil [11 and a variable capacitance diode Dv2. The secondary side tuning circuit is composed of a coil [13] and a variable capacitance diode DV3 connected in parallel to a capacitor C24.

These double-tuned circuits are constructed using variable capacitance diodes D as described above.
'V2. DV3 tunes to the desired channel frequency.

The output from the double-tuned circuit in the VIIF band is supplied to the mixer circuit 23 via an inductor [21] and a matching coil [22].

Next, the circuit operation when receiving the U11F band will be explained.

The voltage applied to the terminal U causes the diodes D7 to D1 to
0,013 is turned on and a voltage is supplied to the drain D of transistor Q1. On the other hand, diode D11 is turned off. The primary side tuning circuit is formed by a parallel circuit of an inductor [17] and a variable capacitance diode Dv2.

The secondary side tuning circuit is formed by a parallel circuit of an inductor [18] and a variable capacitance diode DV3.

'19. '20 is an inductor for adjustment, and the primary side and the secondary side are connected through a connecting window 28. The output of the double-tuned circuit is taken out by the inductor [21 and electromagnetically coupled to the inductor [18] and supplied to the next stage mixer circuit 23.

The coupling between the drain O of the transistor Q1 and the primary side tuning circuit of the band is performed by the terminal N (approximately IPF) of the diode '11 which is turned off and the 2PF capacitor C19. Therefore, the coupling is combined. The sound d is approximately 3PF.If this can be achieved with only the capacitance between the terminals of the diode, it is better to omit the capacitor C11 since it reduces the number of parts.

In this way, the parallel circuits of drain D, DV2, and It is possible to prevent a decrease in output. The output curve of the tuned circuit using this circuit is shown in Figure 4 as a solid line 38.
Indicated by As you can see, within the tJHF(7) band (
470-770Htf7) Tare 7) Output level is equalized.

The coil switch 11, which has one end connected to 019 and the other end grounded in an alternating current manner, is used for peaking.

This is used both as a tuning coil when receiving VHF and as a peaking coil when receiving F.

As explained above, the double tuning circuits 20 and 21 are also used for the variable capacitance tie autos DV2 and DV3 in U-v tuning, which has the advantage of being able to reduce the number of parts.

Next, the transmitter circuit 22 will be explained. This oscillation circuit is a Colpitts type oscillation circuit, where 02 is a transistor for oscillation, and C29 and C3o are collectors of transistor Q2.
Capacitors C and C34 are connected between the emitters and capacitors connected between the base and the emitters, '23. '
2゜ and 25 are coils and inductors selectively connected between the base and collector, C3□ is a capacitor for AC grounding the collector, 26 is an adjustment inductor, [27 is for oscillation stabilization] Inductors Dv4 and DV5 represent variable capacitance diodes for variable oscillation frequency and AFC, respectively. 0 0 is a diode for switching [1/V] to which voltage is supplied from the Vi+ and VL terminals, Vl (turns on when receiving F band.D17 is turned on when receiving VHF band,
This is a diode for switching between low and high bands.

The oscillation operation in the VHF band will be explained. During low band oscillation, a voltage is applied from the V terminal to the diodes O and DG through the diode D4, turning them on. Then, between the collector and the emitter] +l'c29
A capacity of 030 is added to the capacity of . Further, the base-emitter capacitance is the series capacitance of capacitors C31 and 034. And a coil [23,'2. 'l is connected. Low-hand oscillation is performed with this circuit configuration, and the oscillation frequency is varied by applying the variable voltage from the V T OQ terminal to the variable capacitance diode D.
This is done by applying it to v4.

■The difference between the oscillation operation in the high band of the 11F band and the low band oscillation is that the diode D15°D16
The switching voltage supplied to the diode D5 is applied from the terminal VH to the diode D5.
, and the voltage that turns on the diode D1□ is supplied from the terminal VH. Since the coil 24 is short-circuited by the diode 01□, only the coils 1-23 are used for oscillation. Note that the inductance component of 25 is very small for the V1 belt and can be ignored.

Next, the oscillation operation in the UIIF band will be explained. There is no switching voltage supply to diodes D15-D17, so they are turned off. Then, the collector-emick orange becomes only C29, and the capacitance between the base and emitter is CC, which is the terminal ft(
(approximately IPF) or connected in series, and further diode D16
and C7o are connected in parallel, and their combined capacitance becomes a small capacitance of several P or less.

Also, the inductance component connected between the base and collector is the inductor [2, which is the inductance component connected between the base and collector. In this configuration, the output frequency is varied by varying the capacitance of the variable capacitance diode DV4.

Note that during oscillation in the UIIF band, the diode D16 in the coil is off, and the impedance is very large for the IJHF band, so there is no effect.

The U-v oscillation output is supplied to the next stage mixer circuit 23 via the coupling capacitor C36.

Note that the capacitor 038 is for DC cut. 1
~The power supply voltage to the transistor 02 is always supplied from the terminal 8.

As mentioned above, the oscillation circuit 22 includes a diode D15°D1.
By turning on and off 6, the collector of the current transistor
Switch emitter and base-emitter capacitor,
In addition, since the inductance between the collector and base is switched, U and V oscillations can be switched with a simple configuration.
It also has the advantage of being able to double as an oscillation element, reducing the number of parts and the space for assembling the parts.

FIG. 5 shows a modification of the oscillation circuit 22. In FIG. The same parts in FIG. 5 are denoted by the same reference numerals (t b. The explanation thereof is omitted. The oscillation circuit in FIG. 5 is designated by the reference numeral 22'. The difference from the oscillation circuit in FIG. , and Vl(F
The oscillation output of the band is coiled and the coil 28 is electromagnetically coupled to 3.
(output terminal 29).

Also, the oscillation output of the UIIF band is connected to the inductor 1-25.
4-coupled inductor 29 (output terminal 30).

In this way, the method of extracting the oscillation output by U-V separate 74 coupling allows the mixer circuit 23 connected to the next stage of this oscillation circuit to have a 6C current while minimizing the effects of changes in impedance due to changes in temperature characteristics, etc. This has the advantage that the oscillation circuit 22' is less affected by this, and as a result, the oscillation frequency is stable.

Next, the Mikina circuit shown in FIG. 3 will be explained. This mixer circuit has a configuration in which transistors Q and Q4 are connected in cascade, and here double-tuned circuits 20 and 21
The signal from the oscillation circuit 22 is frequency-converted by the signal from the oscillation circuit 22, and is output from the terminal 14 as an I signal. This mi,
The filter circuit is used for both UV and UV.

FIG. 4 shows a specific circuit diagram of the circuit diagram shown in FIG. The parts that differ from the circuit diagram in FIG. 3 are the input filter circuit 16, input tuning circuits 17 and 18, and double tuning circuits 20 and 21, and these parts will be explained.

In the input filter circuit 31 of FIG. 4, the coil '30
and capacitor C40 (47PF), C42 (6
8PF) forms [P[(low-pass filter), and the sixth
It has LPF characteristics as shown in 34 in the figure. coil[
31 and a capacitor C43 (100 OPF) constitute a trap circuit, which has trap characteristics as shown by the dotted line 35 in FIG. Coil shield 32 and capacitor 046
C47 forms a low pass filter (LPF) and has characteristics as shown by 36 in FIG. The parallel circuit of the capacitor C49 and the coil [33 forms a pantoiminator, which prevents image frequencies from 280H11 to 335MH7 from passing through. Coil [34 and capacitor C5o constitute a trap circuit with a frequency of 58.75 MH2.

When receiving low band, π-type LPF (L3o, 'C
4o.

Since the diode 018 connected to the cold side of C42) via the capacitor C41 is turned on by the voltage supplied from the terminal v, the LPF consisting of CC and '3040.42 passes frequencies below approximately 120M82. During high-band reception, the voltage supply from terminals V[ to '' disappears, so diode 018 turns off, and a trap circuit consisting of C becomes a trap at the center frequency of 43.31100HH□, blocking frequency components in the low-band frequency band. are doing. Capacitor C39,4
5, C48 is a coupling capacitor. Furthermore, capacitor C4
1 (68PF) is the low band image frequency (208PF)
~220Htl□), and by connecting this capacitor, the image can be improved by 15 dB compared to the case where it is not connected.

In such an input filter circuit 31, 043. The trap circuit according to [31] can reliably block low-band frequency components, and can prevent cross-modulation or intermodulation interference due to high frequencies generated in the amplification element of the high-frequency amplification circuit 19.

Next, a double tuning circuit 32 is placed before the RF amplification circuit 19. An example in which a single tuning circuit 33 is disposed at the rear stage will be explained with reference to FIG. 4.

In the double tuning circuit 32, first, the low band reception of the VHF band will be explained. The primary side tuning circuit is coil '3
3. '34. It is composed of a variable capacitance diode Dv6 connected in parallel to '3□ and θ. Further, the secondary side tuning circuit is composed of coils [3, to [37] and a variable capacitance diode DV7 connected in parallel. In this case, no voltage is applied to terminals U and VH, so diodes 019 to
022 is off. Capacitors C51 and C55 are for DC cut, and capacitors 052 to 058 are for parallel resonance with the coil.

During high band reception in the VHF band, voltage is supplied from terminal VH, diodes D2o and D22 are turned on, and the primary side of the double-tuned circuit is connected to coil [33 and variable capacitance diode O].
V6. Secondary side is coil 3 and variable capacitance diode Dv
Each consists of 7. And the tuning output is the inductor [4
2 to the high frequency amplification circuit 19.

Note that in the VHF band, the inductance components of inductors [4o to [42] can be ignored.

When receiving the UHF band, the voltage supplied to terminal U turns on diode D19,021, and 1 of the double-tuned circuit turns on.
The secondary side is composed of a parallel resonant circuit of an inductor '40 and a variable capacitance diode DV6, and the secondary side is composed of an inductor '41 and a variable capacitance diode DV7. The F band signal is input by coupling the coil 44 and the inductor 4°. Further, the output of the double-tuned circuit is supplied to the RF amplification circuit 19 by coupling between inductors [41 and [42].

The reason why the input tuning circuit is double-tuned in this way is that when receiving the VIIF signal, the band signal also enters the double-tuning circuit 24, but the selectivity characteristics of the double-tuning circuit are good, so U1 is recommended. This has the advantage that obi codes can be definitely eliminated.

Note that '43' is an adjustment inductor.

Next, the single tuning circuit 33 shown in FIG. 4 will be explained.

First, the low band reception of the VHF band will be explained. Since no voltage is applied to the terminal \rH-U and voltage is applied only to the terminal v, the diodes D23 to D25
Since is off, a single tuned circuit is formed by a parallel resonant circuit of the coils 45 to 47 and the variable capacitance diode DVa.

V[When receiving a single high band, voltage is applied only to terminal VH, so only diode D24 is turned on, and the end of coil 1-46 is grounded by capacitor C63, so the single tuned circuit LL and a variable capacitance diode DB8.

When receiving VHF low and high bands, inductor 4
9 is connected, but this inductance component is small and can be ignored for the VHF band. Capacitor 068 functions as a 1~racking adjustment. The tuning output is output via an inductor '49='5°.

Next, we will explain what happens when a band is received. Since voltage is applied only to terminal U, diodes 0 and 0 are turned on. Thereby, the single tuned circuit is formed by a parallel circuit of the inductor '49 and the variable capacitance diode Dv8. In this case, coil L
One end of 45 is grounded with capacitor C64 and acts as a peaking coil.The tuning output is inductively coupled to inductor 50 and output from it. 8 is for adjusting the resonance frequency.

<Effects of the Invention> According to the multi-band tuner according to the present invention described above, the number of tuners that receive each band of the V frequency band and the frequency band can be reduced in one of the common input tuning circuit, the interstage double tuning circuit, and the oscillation circuit. In addition to sharing the variable capacitance diode with U and V,
Since transistors are shared in at least one stage of the RE increasing middle oscillation stage and the mixer stage, the number of circuit components can be greatly reduced.

In addition, this allows the tuner itself to be significantly downsized, and in recent years there has been a strong demand for electronic components to be lighter, thinner, shorter, and smaller, and this has not only fully satisfied this demand, but also significantly reduced costs. It's something you can lean on.

[Brief explanation of drawings]

FIG. 1 is a circuit block diagram of a broadband reception tuner according to an embodiment of the present invention, FIG. 2 is a circuit block diagram of a modification of FIG. 1, and FIG. 3 is a specific example of the circuit block diagram of FIG. 1. 4 is a specific circuit diagram of the circuit block diagram of FIG. 2, FIG. 5 is a diagram showing a modification of the oscillation circuit section of the circuit diagram shown in FIG. 3, and FIG. FIG. 7 shows a filter characteristic diagram for explaining the input filter circuit shown in the figure, and FIG. 7 shows a circuit block diagram of a conventional broadband reception tuner. 16, 31...Input filter, 17.26...VH
F single-tuned circuit, 18.27...] single-tuned circuit for rivers,
19...RF amplification circuit (high frequency amplification circuit), 20.
24...VHF double tuning circuit, 21, 25...F for 1
Double tuned circuit, 22.22'... (Tatsunki, 23...
Mixer circuit, 29...VHF output, 30...UII
F output, 32...Double tuned circuit, 33...Single tuned circuit, C1-C69...Capacitor, R1-R6...Resistor, 01-Q4...Transistor, D1-D25...
・Diode, Dv1 to DV8...Variable capacitance diode.

Claims (1)

[Scope of Claims] In a multi-band tuner that receives a first band and a second band, at least one of an input tuning circuit, an interstage tuning circuit, and an oscillation circuit receives the first and second bands.
A variable capacitance element common to the first and second bands is used, and a transistor common to the first and second bands is used in at least one of the high frequency amplification circuit, the oscillation circuit, and the mixer circuit. A multi-band tuner featuring: