JPS6066528A - Tuner with double converter system - Google Patents

Abstract

PURPOSE:To improve the capability of elimination of disturbing waves in case of reception of wide-band television signals and make a device small-sized and high- capacity, by providing a mixer, which raises the output of an input circuit part to the first intermediate frequency with the first oscillation signal of the first local oscillator, and a mixer which raises the output of the first intermediate frequency circuit part to the second intermediate frequency with the second oscillation signal of the second local oscillator. CONSTITUTION:An input signal is inputted from input terminals 12 and 13 and is selected by a changeover switch part 11 and is sent to an input circuit part 14. The input signal is subjected to a prescribed processing in this circuit part 14 and is mixed with the oscillation signal of the first local oscillator 15 by the first mixer 17 and is raised to the first intermediate frequency. Meanwhile, a fixed frequency dividing circuit 16 constitutes a part of a PLL frequency synthesizer by a part of the output of the first local oscillator 15. The output signal of the mixer 17 raised to the first intermediate frequency has only the band of a desired channel amplified and selected in the first intermediate frequency circuit part 18 and is raised to the second intermediate frequency with the second local oscillator 19 by a mixer 20. This signal is selected and amplified by the second intermediate frequency circuit part 21 to obtain a signal having a prescribed intermediate frequency from an output terminal 22.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a double converter tuner for receiving broadband television signals such as 0ATV.

The configuration of the conventional tuner and its problems will now be explained with reference to the drawings. FIG. 1 shows a conventional tuner with a reduced number of connections.

In Fig. 1, 1 +d input ^11^; a manual filter that performs the F wave of the input signal applied via child 2, 3 an amplifier that amplifies the output of input filter 1, 4 (I:i
ζ jagged 60:j, ζ jagged 4 which generates the first intermediate frequency by the oscillation frequency of the first local oscillator 5 and the output of the amplifier 3
A filter 7 generates a band F wave from the output of the ζ-giza, 7 generates a second intermediate frequency by the oscillation of the second local oscillator 8 and the output of the filter 6, and 9 amplifies the output of the ζ-giza 7. Output 4: Output 10Vc This is an amplifier that sends out that signal.

In the above configuration, the input signal inputted through the input filter 1M element 2 is converted to θl by the input filter 1 (
The 'Ig signal is amplified by amplifier 3.

Next, at the ζ zigzag 4, the output of the amplifier 3 and the first local oscillator 5
The first intermediate frequency is mixed with the output of the filter 6 and sent to the filter 6.

After applying the F wave in a predetermined band, the output of the Mikitsu-7-(UJ Noil Taro) and the output of the second local oscillator 8 are mixed and sent to the amplifier 9 for amplification.

Note that as the first intermediate frequency, the THF band, for example, 400
M fiz to 600 Ml1zi are used, and the filter 14 is often a helical coil type or hollow coaxial type filter.

By the way, in the double converter method, the uneasy signal (spurious) generated by the input signal and two local excavations is
The lower the first intermediate frequency is, the sooner it occurs, and it is conceivable to improve the performance of the filter 6 for the intermediate frequency F as a countermeasure to remove it.

However, improving the performance of the filter 6 would lead to an increase in the size of the device. In addition, the input filter 3, etc., has a disadvantage in that it is not a system that selects only a specific band, and measures against interference waves at the input are weak.

This has become an important performance as a steel sheet, and more improvements have been made on J-cloth. In order to solve the problem of 1η point, a small and high-performance double controller is used to reduce unwanted radiation and eliminate interference waves J11 when receiving wideband television signals. The purpose is to provide a bark method that is easy to use.

Structure of the Invention The present invention is directed to the first;
Side 1 is performed, and after the first band control, the VC
I-1: an input circuit 3+1 which amplifies the input information signal which has been fully subjected to dynamic gain control, and further performs second band control;
) 1. 7F converts the output of the large input path section, and the third "A" amplifies the output of the ζ jagged means.
A first intermediate frequency circuit section that performs lf control and amplification, and a second intermediate frequency circuit section that converts the output of the first intermediate frequency circuit section into a second intermediate frequency. , the output of the second ζ jagged means? -Jl,
tg purpose.

DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
invent.

FIG. 2 shows block connections of a double converter tuner according to an embodiment of the present invention.

In Fig. 2, 11 indicates the input signal to two input terminals 1.
2. A change-over switch unit that receives an input from 13 and selectively switches the input; 14 is an input circuit unit that performs processing to be described later on the output of the change-over switch unit 11; and 16 is a first pressure-controlled first local oscillator. It is.

16 is a fixed frequency dividing circuit that inputs a part of the output of the first local oscillator 15 and performs fixed frequency division;
It constitutes a part of the frequency 7-senseizer of the se.Lock-Loop) method. 17 is a mixer which inputs the first emission information of the first local oscillator 16 (b) and makes the output of the pedal part 14 a first intermediate frequency; A first intermediate frequency circuit unit selects and amplifies only the band of one channel, and 19 is a second oscillation information signal of the second local oscillator 20. Mixer to make 1 wave number,
Reference numeral 21 denotes a second intermediate frequency circuit section which selects and amplifies only one predetermined channel band from the second intermediate frequency output from the mixer 19, and outputs a power 1-[) to the output terminal 220. In the configuration, 1st input signal is input bell 12.1
The signal is sent to the J oscillation input circuit 14 selected by the selector switch 11 via the selector switch 3, where it is subjected to 9F constant processing, and the first mixer 23 outputs the first local oscillation signal ZK15.
is mixed with the oscillation signal of and raised to the first intermediate frequency.

On the other hand, - part 4C,1 of the output of the first local oscillator 16: I
The J-fixed frequency divider circuit 16 constitutes a part of a PLL type frequency/variable frequencyizer. Now, the output signal of the mixer 17 with the first intermediate frequency VC1 raised is amplified 2 in the band of one desired channel in the skin circuit section 18, and the second local oscillator is 4 Tatsu', :%1g
Therefore, the cost of the second intermediate cylinder cannot be reduced. and the second
It is selected and amplified by the intermediate wave number section 21, and a signal with a constant intermediate frequency of F1 is obtained from the output terminal 22.

Next, using Figures 3 to 7, each item shown in Figure 2 is
I) The function of configuration will be explained in more detail.

The changeover switch section 11 and the input circuit section 14 will be explained using FIG. As shown in FIG. 3, human-powered dry bones are applied to two input terminals 12 and 13i, and the input signal applied to input terminal 12 is based on a control signal 23 (J), and a part of it ( No. 13 is taken out as theta output 0 and switching circuit 1η11125
, one of the input signals is selected and sent to the filter 26. The filter 26 is basically a low-pass F wave filter 17 whose cutoff frequency can be varied so as to pass signals within the receiving band.

Apart from that, gain control is performed by the AGO circuit 2,
Next, a signal amplifier 28 amplifies the signal and a filter 29
For example, the first filter 29 is 54 to 1.
02MIIz, the second is 102MIIz ~ 252 or 28
2MIIZ+3rd is 262 or σ282M1lz~a56
It is divided into three bands up to MIIz.

Note that the filter 29 has a varactor dimate (4j-z shown in the figure), and from this diode) 1"1 change;
The first area is structured as follows. Then, the output of the filler 29 is sent to the mixer 17&ζ)7<jlj shown in FIG. 2IC.

Next, the first intermediate frequency circuit section 18 will be explained using FIG. 4. FIG. 4
;'j After that, the band pass filter 31 makes one change,
Select the L signal. Filter 31td (bandwidth 6MIIz, low tuning '11L body loss for miniaturization,
High permittivity dielectric material, e.g. dielectric A-ε, = 35
, 1. An 6 = 1 x 10 -4 is used to make the configuration compact. 0 Thereafter, the signal is again amplified via the amplifier 32 and applied to the mixer 20 shown in FIG.

Next, the second intermediate frequency circuit section 21 (C) will be explained using FIG.

The signal converted to the second intermediate frequency by the mixer 20 is intensified by IW11 and then passed through the band-pass filter 34 to remove interference from adjacent channels other than the desired band. The audio signal and video signal of Use a combination of interference filters, surface wave filters, etc.

Next, the first local oscillator 15 will be explained using VC FIG. In the first local oscillator 15, as shown in FIG.
The oscillation frequency is controlled by the voltage applied from the terminal 37 to the oscillation frequency. Then, it is amplified by two stages of buffer amplifiers 38 and 39, and divided into two by a distribution circuit 40, and most of the signals are sent out to drive the mixer 17 shown in FIG. 2, and the rest is by PLL system. The signal is sent to a fixed frequency divider circuit 16 shown in FIG. 2 as a signal source for configuring the entire frequency synthesizer.

Next, the second local oscillator 19 will be explained using FIG. 7.

The second local oscillator 19 is connected to the oscillator 41 as shown in FIG.
A varactor diode (not shown) is added to the AFC signal terminal 42 so that the receiver as a whole can be stabilized by AFG.

In addition, a mechanical tuning mechanism 43 is provided for fine adjustment of the oscillation frequency to facilitate frequency setting during mass production, and its output is connected to terminal 4.
4 to the mixer 20 shown in FIG. 2(C).

Next, FIG. 8 shows a specific circuit diagram of the block configuration shown in FIG. 2(C).

In FIG. 8, 11 is a changeover switch section, 12.1
3 is an input terminal, 14 is an input circuit section, 15 is a first local oscillator, 16 is a fixed frequency divider circuit, 17°20Vj, mixer, 1
8.21 are the 1st. The second intermediate frequency circuit section 19 is a first local oscillator, and each corresponds to the same diagram as shown in FIG.

First, input signals a and b are sent to changeover switch section 11 via input terminals 12 and 13, and part of input signal a from input terminal 12 is taken out from terminal 11a as a data signal. Switching of the switch in the changeover switch section 11 is performed by a switching signal applied to the terminal 11b.

Next, in the input circuit section 14, the above-mentioned input filter, AG
O section, amplifier and filter connect terminals 14a and 14b.
, 14c performs three band switching, for example, the receiving frequency is set to 64 MIIZ to 456 MIIz, and the gain is set to #4+10 dB without AGO. The mixer 17 performs processing using a diode mixer and one stage intermediate amplifier, and the first local oscillator 15
The received signal is raised to the first intermediate frequency of the 1.5 G11z band, for example.

On the other hand, the first oscillator 15Vi, frequency 1564~1956M
1lz l) J variable frequency, and is controlled by the control input of the unseizer applied to the terminal 15a,
The signal of the PLL configuration is connected to the terminal 16 of the fixed frequency divider circuit 16.
taken out from a. Now, the first one that was ejaculated by mixer 17
The intermediate frequency signal is tuned by the first intermediate frequency circuit section 18 only to a desired frequency band. The specific circuit of the first intermediate frequency circuit section 18 shown in FIG. 8 is shown in FIG.
Since there are two roofs around the corner and Xuyu-dong bow crystal furnace, the width of the area is 6 MIIz.
After that, the first intermediate frequency signal is input to and output from a mixer 19Vc, amplified, and converted into the second intermediate frequency band, for example, 415M+1Z band.

At this time, the second local oscillator 19 is a fixed oscillator with an AFC function, and the AFC i'i signal is applied to the terminal 19a.
For example, the oscillation frequency is set to 1454.25 Mllz. 3 After that, it passes through the second intermediate frequency circuit section 21,
The output is obtained from the y1m child 22. Note that channel selection is performed by a PLL type frequency synthesizer, and a PLL signal is taken out from a terminal 16b by a frequency dividing circuit 16V.

DC galvanic corrosion is applied to the disconnected terminal 15b! 1111, and is supplied with, for example, 16V DC.

According to the above configuration, the receiving frequency is 54 to 456 MIIZ.
So, the total profit and insurance is 33±2 dB, lll'i'i
High characteristics with an index of 1QdB or less, only in size 110x6
It can be realized with a small device of 0x20 order and a volume of 132 d or less. In addition, as for the interference characteristics, it is possible to obtain intermodulation characteristics of -60 dB or less using only a diode noncle balanced mixer. A specific embodiment of the receiver will be described below.

That is, the tuner shown in FIG. 2 is provided as a tuner section 46 in FIG. 9. First, as explained in FIG. 2, two input signals a and b are sent to the tuner section 45 via the input terminals 12 and 13. The output C passes through a television receiver set circuit i%46, and after predetermined processing, a video signal d can be obtained. Then, stabilization can be achieved by applying the AFG signal input unit 45V sent from the television receiver set circuit unit 46.

On the other hand, the receiving channel is selected by a 1d PLL synthesizer, and in response to an instruction from the input means 47 such as a keyboard or a channel selection button, the PLL circuit section 48 divides the frequency signal f from the tuner section 45 to obtain the reference frequency. , an error signal q is sent out to stabilize the voltage controlled oscillator of the tuner section 46 by applying a phase delay.

The effects of the invention include an input circuit section that amplifies the input signal that has been subjected to automatic U-QRI control after the first band control and further performs second band control; a first mixer means for converting the output of the input circuit section into a first intermediate frequency; and a first intermediate frequency circuit section for amplifying the output of the mixer means to perform third band control and further performing amplification. and a second mixer means for converting the output of the first intermediate frequency circuit section into a second intermediate frequency;
1J Amplifying the output of the second mixer means to perform the fourth band control, and by providing a second intermediate frequency circuit for further amplification, when receiving Prebi No. 11 of the wide area, Suppressing unarmored beams as much as possible, creating interference waves
It can be configured in a smaller size than Jilt, and its effects are great.

In particular, it has a doubling effect on all channel reception type tuners centered around C1i AT V ff.

[Brief explanation of the drawing]

Fig. 1 is a block wiring diagram of a conventional tuner, Fig. 2 is a block wiring diagram of a double controller <-evening type tuner according to an embodiment of the present invention, and Fig. 3 is a ψ switch section and input circuit of the same tuner. Figure 4 is a block wiring diagram of the tuner's first intermediate frequency circuit, and Figure 5 is a block wiring diagram of the tuner's first intermediate frequency circuit.
Figure 6 is a block wiring diagram of the second intermediate frequency circuit section of the tuner, Figure 6 is a block wiring diagram of the first local oscillator of the tuner, Figure 7 is a block wiring diagram of the second local oscillator of the tuner, FIG. 8 is a specific circuit diagram of the tuner, and FIG. 9 is a block diagram of a receiver using the tuner. 11-80. Changeover switch section, 14...Input circuit section, 15...First local oscillator, 16...
...Fixed frequency divider circuit, 17, 20...Mixer, 1
8...First intermediate frequency circuit section-19...
Second local oscillator, 21... second intermediate frequency circuit section. Name of representative JJJ person: Patent attorney Toshio Nakao and one other person Figure 4 Figure 6

Claims (1)

[Claims] (1) First band control is performed on the input signal, and the input signal subjected to automatic gain control after the first band control is amplified, and further a second band control is performed on the input signal. an input circuit section that performs control;
a first mixer means for converting the output of the input circuit section into an intermediate frequency; a first intermediate frequency circuit section for amplifying the output of the mixer means to perform third band control and further performing amplification; a second mixer means for converting the output of the first intermediate frequency circuit section into a second intermediate frequency; a second mixer means for amplifying the output of the second mixer means to perform fourth band control; A double converter tuner equipped with an intermediate frequency circuit section. (2) The input circuit section inputs two input signals, selects one of the signals, and performs the first band control. (3) The F-wave device (of the input circuit section that performs the second band control) 1st 54
M llz to 102 Mllz, 2nd to 102 MI
2. The dub/record inverter type tuner according to claim 1, wherein the characteristic is to divide the third band into three bands, from Iz to 252 Mllz and from 252 MIIZ to 456 MIIZ. (4) r of the input circuit jf111 that performs second band control
Wave 2:; the first is from 54 MIIz to 102 M1lz,
2nd from 102 MIIz to 262 Milz, 3rd f
The double converter type tuner according to claim 1, characterized in that the tuner is divided into three bands from 282 Mllz to 456 MIIZ. (6) The double converter type tuner according to claim 1, wherein the first mixer has a local oscillator and is provided with a barac diode for making the oscillation frequency variable. The double converter type tube according to claim 1, characterized in that the tube has a ζ zigzag shape and its intermediate frequency is from 1400M11z to 1600MIIZ. (a) P of the second intermediate frequency circuit section that performs the fourth band control
Be sure to use a bandpass filter! (The double converging force tuner according to claim 1, which is the key feature. A converter system according to claim 1, characterized in that it is used in combination.