JPH0779473B2 - Receiver - Google Patents
ReceiverInfo
- Publication number
- JPH0779473B2 JPH0779473B2 JP17954488A JP17954488A JPH0779473B2 JP H0779473 B2 JPH0779473 B2 JP H0779473B2 JP 17954488 A JP17954488 A JP 17954488A JP 17954488 A JP17954488 A JP 17954488A JP H0779473 B2 JPH0779473 B2 JP H0779473B2
- Authority
- JP
- Japan
- Prior art keywords
- frequency
- band
- intermediate frequency
- signal
- uhf
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Landscapes
- Superheterodyne Receivers (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明はVHF・UHFテレビ放送帯及びBS−IF帯の信号を受
信する受信装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver for receiving signals in VHF / UHF television broadcasting band and BS-IF band.
従来の技術 近年、テレビ放送は地上波を用いたVHF・UHF放送のほか
にSHF帯を用いた衛星放送が行なわれており、CATV放送
ではVHF・UHFのほかに1GHz帯なども用いられ、チャンネ
ル数も年々増大している。また、変調方式についてもAM
変調のみならず、FM変調も用いられたりしており放送の
種類は多種多様になってきている。以下図面を参照しな
がら、上述した多種多様の放送を受信する受信方式の一
例について説明する。第３図は従来の受信方式のブロッ
ク図を示すものである。第３図において、301〜305、32
5,326は端子、306〜308は入力フィルタ、309〜311はバ
ンドパスフィルタ、312〜314は増幅器、315〜318はミキ
サ、319〜322は発振器、323はAM復調器324はFM復調器で
ある。VHF・UHF帯を用いたAMの地上放送信号あるいはVH
F・UHF帯を用いたCATV放送信号が端子301に加えられる
と第１の入力フィルタ312で帯域制限をうけ第１のミキ
サにおいて第１の発振器319の信号と混合され一定の第
１中間周波数に周波数変換され（ここで受信するチャン
ネルの周波数に応じて発振器319の端子325の端子電圧に
より周波数が変る）。増幅器313で増幅され第１のバン
ドパスフィルタ309で帯域制限されミキサ316で発振器32
0の信号と混合され第２の中間周波数に周波数変換され
第２のバンドパスフィルタ310で帯域制限されAM復調器3
23でAM復調されビデオ信号となり端子309に出力され
る。ケーブルで伝送されてきたBS−IF帯のFM信号あるい
は、SHF帯のFM衛星放送信号はパラボラアンテナでBS−I
F帯に変換され端子303に加えられ第３の入力フィルカタ
308で帯域制限され増幅器314で増幅されミキサ318で発
振器318の信号と混合され第３の中間周波数に周波数変
換され（ここで、受信チャンネルに応じて端子326の電
圧によりう発振器322の周波数が変る。）バンドパスフ
ィルタ311で帯域制限されFM復調器324でFM復調されビデ
オ信号となり端子305から出力される。VHF・UHF帯を用
いてケーブルで伝送されてきたFM信号は端子302に入力
され入力フィルタ307で帯域制限されミキサ317で発振器
321の信号と混合してBS−IF帯にアップコンバートして
端子303に入力して端子305からビデオ信号が取り出され
る。2. Description of the Related Art In recent years, in addition to VHF / UHF broadcasting using terrestrial waves, satellite broadcasting using the SHF band is being performed for television broadcasting, and in CATV broadcasting, 1 GHz band is also used in addition to VHF / UHF. The number is increasing year by year. Also, regarding the modulation method, AM
Not only modulation, but also FM modulation is used, and the types of broadcasting are becoming diverse. An example of a receiving system for receiving the above-mentioned various types of broadcasting will be described below with reference to the drawings. FIG. 3 shows a block diagram of a conventional receiving system. In FIG. 3, 301 to 305, 32
5,326 are terminals, 306 to 308 are input filters, 309 to 311 are bandpass filters, 312 to 314 are amplifiers, 315 to 318 are mixers, 319 to 322 are oscillators, 323 is an AM demodulator 324 and an FM demodulator. AM terrestrial broadcast signal using VHF / UHF band or VH
When a CATV broadcast signal using the F / UHF band is applied to the terminal 301, the band is limited by the first input filter 312 and mixed with the signal of the first oscillator 319 in the first mixer to have a constant first intermediate frequency. The frequency is converted (the frequency changes depending on the terminal voltage of the terminal 325 of the oscillator 319 according to the frequency of the channel received here). Amplified by amplifier 313, band-limited by first bandpass filter 309, oscillator 32 by mixer 316
The AM demodulator 3 is mixed with the signal of 0, frequency-converted to the second intermediate frequency, and band-limited by the second bandpass filter 310.
AM demodulation is performed at 23 and a video signal is output to the terminal 309. The BS-IF band FM signal or SHF band FM satellite broadcast signal transmitted by the cable is BS-I
Converted to F band and added to terminal 303
The band is limited by 308, amplified by the amplifier 314, mixed with the signal of the oscillator 318 by the mixer 318, and frequency-converted to the third intermediate frequency (where the frequency of the oscillator 322 is changed by the voltage of the terminal 326 depending on the receiving channel). The band is limited by the band pass filter 311 and FM demodulated by the FM demodulator 324 to become a video signal, which is output from the terminal 305. The FM signal transmitted by the cable using the VHF / UHF band is input to the terminal 302, the band is limited by the input filter 307, and the oscillator is generated by the mixer 317.
It is mixed with the signal of 321 and up-converted to the BS-IF band, input to the terminal 303, and the video signal is taken out from the terminal 305.
発明が解決しようとする課題 しかしながら上記のような構成では多種多様の信号を受
信するために回路がたいへん複雑になっていた。本発明
は上記課題に鑑み多種多様の信号を簡単な構成で妨害排
除能力の高い受信装置を提供するものである。However, in the above-mentioned configuration, the circuit is very complicated because it receives a wide variety of signals. SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a receiver that has a simple structure and has a high interference rejection capability for a wide variety of signals.
課題を解決するための手段 上記課題を解決するために本発明の受信装置は受信信号
をVHF・UHF帯の最高周波数の２倍以上でBS−IF帯の最低
周波数の２倍以下の第１の中間周波数に周波数変換する
第１のミキサと第１の中間周波数を第２の中間周波に変
換する第２のミキサを備えたものである。Means for Solving the Problems In order to solve the above-mentioned problems, the receiving device of the present invention has a first received signal whose frequency is at least twice the maximum frequency of the VHF / UHF band and at most twice the minimum frequency of the BS-IF band. It is provided with a first mixer for converting a frequency to an intermediate frequency and a second mixer for converting the first intermediate frequency to a second intermediate frequency.
作用 以上の構成により、VHF・UHF帯及びBS−IF帯の受信が簡
単で、しかも防害に強い受信装置が可能となる。Operation With the above configuration, it is possible to provide a receiving device that is easy to receive in the VHF / UHF band and the BS-IF band and that is highly resistant to damage.
実施例 以下本発明の一実施例の受信方式について、図面を参照
しながら説明する。第１図は本発明の実施例における受
信方式のブロック図を示すものである。第１図におい
て、101〜104は端子、105〜106は入力フィルタ、107〜1
08は増幅回路、109〜110はミキサ、111〜112は発振器、
113〜115はバンドパスフィルタ、116はAM復調器、117は
FM復調器、118は発振器111の周波数を受信周波数に応じ
て変える端子、119はAMかFMかにより発振器112の周波数
を変える端子である。101に加えられたVHF・UHF帯の信
号（AM波でもFM波でもよい）は、入力フィルタ105で帯
域制限されBS−IF信号（AM波でもFM波でもよい）は入力
フィルタ106で帯域制限され増幅器107で増幅され、ミキ
サ109で発振器111の信号と混合されて第１の中間周波数
に周波数変換され、増幅器108で増幅されバンドパスフ
ィルタ113で帯域制限されミキサ110で発振器112の信号
と混合され第２の中間周波数に変換される。ここで第２
の中間周波数は受信信号がFMかAMかで復調器に加えるべ
き周波数となる。もちろんFM復調とAM復調が同じ周波数
で可能であるならば単一の周波数でよい。第２図は本発
明の実施例における上記、第１の中間周波数と、チャネ
ル間相互変調妨害の関係を示すグラフである。周波数変
換を行うミキサ109ではミキサ109の２次の非線形性によ
りチャネル間相互変調妨害が第１の中間周波数に妨害を
与える。今、発振器の周波数が第１中間周波数と受信周
波数の和の場合、チャネル間相互変調妨害は次式で表わ
されることが知られている。Embodiment A receiving system according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a block diagram of a receiving system in an embodiment of the present invention. In FIG. 1, 101 to 104 are terminals, 105 to 106 are input filters, 107 to 1
08 is an amplifier circuit, 109 to 110 are mixers, 111 to 112 are oscillators,
113 to 115 are bandpass filters, 116 is an AM demodulator, and 117 is
An FM demodulator, 118 is a terminal for changing the frequency of the oscillator 111 according to the reception frequency, and 119 is a terminal for changing the frequency of the oscillator 112 depending on whether AM or FM. The VHF / UHF band signal (AM wave or FM wave) added to 101 is band-limited by the input filter 105, and the BS-IF signal (AM wave or FM wave) is band-limited by the input filter 106. The signal is amplified by the amplifier 107, mixed with the signal of the oscillator 111 by the mixer 109, frequency-converted to the first intermediate frequency, amplified by the amplifier 108, band-limited by the bandpass filter 113, and mixed with the signal of the oscillator 112 by the mixer 110. Converted to a second intermediate frequency. Second here
The intermediate frequency of is the frequency to be added to the demodulator when the received signal is FM or AM. Of course, if FM demodulation and AM demodulation are possible at the same frequency, a single frequency will do. FIG. 2 is a graph showing the relationship between the above-mentioned first intermediate frequency and inter-channel intermodulation interference in the embodiment of the present invention. In the mixer 109 that performs frequency conversion, inter-channel intermodulation interference causes interference at the first intermediate frequency due to the second-order nonlinearity of the mixer 109. It is now known that inter-channel intermodulation interference is represented by the following equation when the frequency of the oscillator is the sum of the first intermediate frequency and the reception frequency.
fu−fd＝2fi1 ……（１） fu＋fd＝fi1 ……（２） fu−fd＝fi1 ……（３） ここで、 fu:妨害信号 fd:受信信号 fi1:第１の中間周波数である。fu-fd = 2f i1 (1) fu + fd = f i1 (2) fu-fd = f i1 (3) where fu: interference signal fd: received signal f i1 : first intermediate frequency Is.
第２図において、VHF・UHF帯の放送帯を50MHzから890MH
z、BS−IF帯を950MHzから1450MHzとする。ここで上記
（１）〜（３）を示す直線が放送帯を示す放送帯域を通
った場合妨害が存在する。したがって妨害が存在しない
ためには、 fi1＞2900MHz ……（４） 1780MHz＜fi1＜1900MHz ……（５） （４）、（５）のどちらかの条件を満足してればよい。
しかしながら（４）の場合は2900MHz以上となり周波数
が高くデバイスの性能が十分ではない。したがって
（５）の1780MHzから1900MHzとした場合の方が性能面、
コスト面で有利である。このように第１の中間周波数を
1780MHzから1900MHzの間に選定することにより比較的低
い第１の中間周波数で相互変調妨害のない受信が可能で
ある。In Fig. 2, the VHF / UHF broadcasting band is changed from 50MHz to 890MH.
z, BS-IF band from 950MHz to 1450MHz. Here, when the straight line indicating (1) to (3) passes through the broadcast band indicating the broadcast band, there is interference. Therefore, in order for there to be no interference, it is sufficient that either of the conditions f i1 > 2900 MHz (4) 1780 MHz <f i1 <1900 MHz (5) (4) or (5) is satisfied.
However, in the case of (4), the frequency is higher than 2900MHz and the frequency is high and the device performance is not sufficient. Therefore, the performance is better when changing from 1780MHz to 1900MHz in (5),
It is advantageous in terms of cost. Thus the first intermediate frequency
By selecting between 1780MHz and 1900MHz, reception without intermodulation interference is possible at a relatively low first intermediate frequency.
発明の効果 以上のように本発明は、VHF・UHF帯の最高周波数以上で
とBS−IF帯の最低周波数の２倍の周波数以下の周波数に
第１の中間周波数を選ぶダブルスパーという構成により
VHF・UHF帯及びBS−IF帯の受信を簡単でしかも妨害に強
い受信装置が可能となった。EFFECTS OF THE INVENTION As described above, the present invention is configured by the double spur which selects the first intermediate frequency at a frequency higher than the highest frequency of the VHF / UHF band and lower than twice the lowest frequency of the BS-IF band.
A receiver that can easily receive VHF / UHF band and BS-IF band and is strong against interference has become possible.
【図面の簡単な説明】 第１図は本発明の第１の実施例における受信装置のブロ
ック図、第２図は第１図における第１の中間周波数の範
囲を表すグラフ、第３図は従来の受信装置のブロック図
である。 101……Ｖ・UHF信号、102……BS−IF信号、105,106……
入力フィルタ、114,115……BPF、116……AM復調器、117
……FM復調器。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a receiving apparatus according to a first embodiment of the present invention, FIG. 2 is a graph showing the range of the first intermediate frequency in FIG. 1, and FIG. 3 is a block diagram of the receiving device of FIG. 101 …… V ・ UHF signal, 102 …… BS-IF signal, 105,106 ……
Input filter, 114,115 …… BPF, 116 …… AM demodulator, 117
... FM demodulator.
Claims (3)
倍以上でBS−IF帯の最低受信周波数の２倍以下である第
１の中間周波数に上記VHF・UHFのTV放送帯及びBS−IF帯
の受信信号を周波数変換する第１のミキサ回路と上記第
１の中間周波数を第２の中間周波数に周波数変換する第
２のミキサ回路とを具備することを特徴とする受信装
置。1. A maximum reception frequency of 2 in the VHF / UHF TV broadcasting band.
The first mixer circuit for frequency-converting the received signals of the VHF / UHF TV broadcasting band and the BS-IF band to the first intermediate frequency which is more than twice and less than twice the minimum receiving frequency of the BS-IF band, and the above. A second mixer circuit for frequency-converting the first intermediate frequency into a second intermediate frequency.
放送帯の最高受信周波数の２倍以上でｎ＋１番目に周波
数の高い放送帯の最低受信周波数の２倍以下である第１
の中間周波数に上記２個以上の放送帯の受信信号を周波
数変換する第１のミキサ回路と上記、第１の中間周波数
を第２の中間周波数に周波数変換する第２のミキサ回路
とを具備することを特徴とする受信装置。2. A first reception frequency which is at least twice as high as a maximum reception frequency of a broadcast band having the nth highest frequency of two or more broadcast bands and is twice or less as high as a lowest reception frequency of a broadcast band having the (n + 1) th highest frequency band.
A first mixer circuit that frequency-converts the reception signals of the two or more broadcast bands to the intermediate frequency of 1 and a second mixer circuit that frequency-converts the first intermediate frequency to a second intermediate frequency. A receiving device characterized by the above.
より変えることを特徴とする請求項（１）または（２）
のいずれかに記載の受信装置。3. The method according to claim 1, wherein the second intermediate frequency is changed according to the modulation system of the received signal.
The receiving device according to any one of 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17954488A JPH0779473B2 (en) | 1988-07-19 | 1988-07-19 | Receiver |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17954488A JPH0779473B2 (en) | 1988-07-19 | 1988-07-19 | Receiver |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0229184A JPH0229184A (en) | 1990-01-31 |
| JPH0779473B2 true JPH0779473B2 (en) | 1995-08-23 |
Family
ID=16067604
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17954488A Expired - Lifetime JPH0779473B2 (en) | 1988-07-19 | 1988-07-19 | Receiver |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0779473B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2501370B2 (en) * | 1990-10-11 | 1996-05-29 | 三菱電機株式会社 | Television receiver |
| JP2007059154A (en) * | 2005-08-23 | 2007-03-08 | Fujitsu Ltd | Two-point contact type socket |
-
1988
- 1988-07-19 JP JP17954488A patent/JPH0779473B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0229184A (en) | 1990-01-31 |
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