JPH0243883A - Measuring instrument for television relay broadcast equipment - Google Patents

Abstract

PURPOSE:To obtain a small sized and inexpensive television relay broadcast equipment measuring instrument by generating a reception signal including 3 frequency components of a desired reception channel frequency based on an RF signal of a local oscillating frequency and three IF signals so as to eliminate undesired spurious components. CONSTITUTION:A reception station oscillator 6 in order to decide a desired reception channel frequency fCH outputs a local oscillation frequency signal f0 corresponding to the RF signal. A double balanced mixer 16 mixes the signal of the local oscillation frequency f0 amplified by a broad band amplifier 13 with a video signal V from an IF signal generator 14, a color signal S and an audio signal A and gives a reception signal B' at a prescribed level to an input filter 1 of a television relay broadcast equipment via a variable attenuator 12. Since the input filter 1 eliminates the undesired frequency component, the reception signal given to the receiver 2 has only the desired reception channel frequency fCH. Thus, the inexpensive television relay broadcast equipment measuring instrument with simple constitution is obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a measuring device that generates a received signal for testing a television relay broadcaster, and in particular to an inexpensive television relay broadcaster measuring device with a simplified configuration. It is related to.

[Prior Art] FIG. 5 is a block diagram showing a conventional television relay broadcaster measuring device.

In the figure, (1) is the input filter into which the received signal B for measurement is input, (2) is the receiver connected to the input filter (1), and (3) is the transmitter connected to the receiver (2). vessel,
(4) is a power amplifier connected to the transmitter (3); (5)
is the output filter connected to the power amplifier (4), (6)
is a receiving local oscillator connected to the receiver (2), and (7) is a transmitting local oscillator connected to the transmitter (3), and these (1) to (7) constitute a television relay broadcaster. There is.

(8) to (10) are RF signal generators that generate RF multiplied signals of UHF or VHF, and each RF multiplied signal frequency is video frequency fv, color frequency rs, and audio frequency fA within the desired reception channel frequency fCH. corresponds to each. (11) represents each RF signal generator (8) to (10)
(12) is a combiner (12) that combines RF multiplied signals from
This is a variable attenuator for inputting the signal from 11) to the input filter (1) as a received signal B at a predetermined level.

Next, the operation of the conventional television relay broadcaster measuring device shown in FIG. 5 will be described with reference to the characteristic diagram in FIG. 6.

Generally, in order to measure and test a television relay broadcaster, each 6th I2
It is necessary to input a received signal B having a video frequency fV, a color frequency fS, and an audio frequency fA having relative levels such as 1.

Therefore, each frequency rv, rs and f required for the measurement test
Three RF signal generators (8) to (10) set to A
are prepared, and the RF signal generators (8) to (10) are synthesized by an RF multiplier signal synthesizer (11), and a received signal B of a specified level is generated by a variable attenuator (12). .

A received signal B consisting of a received channel frequency fc) is input to a receiver (2) via an input filter (1), and is used for characteristic test measurement and adjustment of a television relay broadcaster.

However, the TV relay broadcasting machine is installed on top of the mountain.
Carrying a measuring device including three large-scale RF signal generators (8) to (10) requires a lot of labor and is not economical.

[Problems to be Solved by the Invention] As described above, the conventional television relay broadcaster measurement device uses three RF signal generators (8) to (10) to generate the received signal B that serves as a reference. , each RF multiplied signal receiving channel frequency is set to fcH, so there is a problem that the configuration cannot be simplified and cost reduction cannot be realized.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a television relay broadcaster measuring device that has a simple configuration and is inexpensive.

(Means for Solving the Problems) A television relay broadcaster measuring device according to the present invention includes an RF signal generating means for generating an RF multiplied signal of a local oscillation frequency, and r(
A wideband amplifier that amplifies the F signal over a wideband, a video signal,
I generates an IF multiplied signal consisting of a color signal and an audio signal
This system includes an F signal generator and a DBM that generates a reception signal including a desired reception channel frequency based on three IF signals that are amplified RF multiplied signals of the local oscillation frequency.

[Operation] In the present invention, a received signal containing three frequency components of a desired receiving channel frequency is generated based on an RF multiplied signal of a local oscillation frequency and three IF multiplied signals, and an input filter in a television relay broadcaster is generated. removes unnecessary spurious components from the received signal and inputs it to the receiver.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure is a block diagram showing one embodiment of the present invention.
) to (7) and (12) are the same as described above.

(13) is a wideband amplifier connected to the receiving local oscillator (6), which amplifies the local oscillation frequency fO for determining the receiving channel frequency fcH over a wide band.

Reference numeral (14) denotes an IF (intermediate frequency) signal generator of a predetermined frequency, which generates three IF multiplied signals corresponding to the video signal (2), color signal S, and audio signal A, respectively.

(15) is a broadband amplifier (13) and an IF signal generator (1
4) DBM (double balanced mixer) connected to
The video signal V and the color signal S, which include the IF multiplied signal, are
and based on the audio signal A and the local oscillation frequency rO,
A signal containing a video frequency "V, a color frequency fs, and an audio frequency rA within the desired reception frequency fC)l is generated.

Next, while referring to the characteristic diagrams in FIGS. 2 and 3,
The operation of the embodiment of the present invention shown in the figure will be explained.

The receive local oscillator (6) sets the desired receive channel frequency f
In order to determine cH, a signal with a local oscillation frequency [0] corresponding to the RF multiplied signal is output. This signal is amplified by a wideband amplifier (13) and input to D B M (15). On the other hand, the IF signal generator (14) has three IF
Signals VS and A are generated and input to DBM (15).

D B M (15) is the amplified local oscillation frequency f
o signal and the video signal from the IF signal generator (14) ■
, the color signal S, and the audio signal A are mixed to generate a signal whose relative levels have a frequency distribution as shown in FIG. This signal becomes a received signal B' at a predetermined level via a variable attenuator (12), and is input to an input filter (1) of a television relay broadcaster.

As shown in FIG. 2, in addition to the desired reception channel frequency fCH, the reception signal B' has a local oscillation frequency ro and a spurious frequency component element A symmetrical to the reception channel frequency fCH, centering on the local oscillation frequency f. ', fS' and rv'.

However, since the input filter (1) removes unnecessary frequency components, the received signal input to the receiver (2) only has the desired reception channel frequency rCH as shown in FIG.

In this way, the RF signal generators (8) to (1) shown in FIG.
0) without using the desired receive channel frequency rcH
The received signal can be input to the receiver (2). Further, there is no need to set the RF multiplied signal frequency to three frequencies corresponding to the video frequency, color frequency, and audio frequency.

In the above embodiment, the receiving local oscillator (6) is used as an RF signal generating means for generating an RF multiplied signal of the local oscillation frequency fo.
The output signal of this receiving local oscillator (6) was branched using
Two RF signal generators (18) may be used. In this case as well, the received signal B' with the frequency distribution shown in FIG. 2 is generated, but by passing it through the input filter <2), The received signal with only the receiving channel frequency fCH is sent to the receiver (
2).

In addition, in the case of Fig. 4, the RF signal generator used <18)
Since there is only one unit, the size of the entire measuring device is not increased.

[Effects of the Invention] As described above, according to the present invention, the RF of the local oscillation frequency
RF signal generation means for generating a doubled signal, a wideband amplifier for amplifying the RF doubled signal over a wide band, an IF signal generator for generating an IF signal consisting of a video signal, a color signal and an audio signal, and three amplified RF doubled signals. Based on the IF multiplied signal,
D to generate a received signal containing the desired receive channel frequency.
BM, unnecessary spurious components are removed from the received signal and input to the receiver via the input filter in the TV relay broadcaster, so multiple RF signal generators tuned to three frequencies can be used. This eliminates the need to use a TV relay broadcaster measurement device that is small and inexpensive.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a characteristic diagram without showing the frequency distribution of the received signal in FIG. 1, and FIG.
The figure is a characteristic diagram showing the frequency distribution of the received signal input to the receiver in Fig. 1, Fig. 4 is a block diagram showing another embodiment of the present invention, and Fig. 5 is a conventional TV relay broadcasting machine measurement. FIG. 6 is a block diagram showing the apparatus, and a characteristic diagram showing the frequency distribution of the received signal in FIG. (1)...Input filter (2)...Receiver (6
)...Reception local oscillator (13)...Wideband amplifier (14)...IF signal generator (15)...DBM
(18)...RF signal generator fcH...Reception channel frequency r,...Local oscillation frequency ■...Video signal S...Color signal A...
- Audio signal B'... Received signal direction. In the figure, the same reference numerals indicate the same or corresponding parts. flood map

Claims (1)

[Claims] An input filter, a receiver into which a received signal is input through the input filter, and a receiving local oscillator that generates an RF signal at a local oscillation frequency for setting a receiving channel frequency of the receiver. RF signal generating means for generating the RF signal; and RF signal generating means for generating the RF signal.
a wideband amplifier that amplifies a signal over a wideband; an IF signal generator that generates an IF signal consisting of a video signal, a color signal, and an audio signal; and based on the amplified RF signal and the IF signal,
a DB that generates a received signal including the received channel frequency;
A television relay broadcaster measuring device comprising: M.