JP3320946B2 - Test equipment for signal receivers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a signal generating device and the information processing apparatus, an information display device or al used is disposed on the transmission path between the signal receiving apparatus and a signal reproducing apparatus for an electric / optical converter, etc.
It is, relates to signal receiving apparatus for testing devices to be transmitted to the conversion settings to signal receiving apparatus and a signal reproducing apparatus a required reference potential reference potential of the signal from the signal generator, particularly a signal receiving apparatus and a signal reproducing apparatus The present invention relates to a test device for a signal receiving device , which can convert and set a reference potential of a signal input to a device to various potentials, and is useful for confirming operation of the device.

[0002]

2. Description of the Related Art Usually, a signal generating device and a signal receiving device or a signal reproducing device are set so that the reference potential of a signal in each device is the same , and a system is assembled. Generally , the reference potential of the signal generator is set to the ground level, and the reference potential of the signal receiver is set to the ground level correspondingly. However, depending on the signal generator, the reference potential of the transmission signal may be reduced when assembling the system.
Specific particular level to the signal generator, the rare, there are also cases so that to set the reference potential such as a dozen V. Moreover, the variable potential range of the reference potential is at most extremely small as about 1 to 2 V.

[0003] Therefore, a problem that is assumed when the signal receiving apparatus is used in combination with signal generating device of a different reference potential, whether i.e. the need to interface matching the signal receiving apparatus, an interface matching If not taken signal generator by Ri signal receiving apparatus to a reference potential <br/> set in the on properties, whether from undergoing any influence on the reliability and the like, and tested under the same conditions as production conditions it kept the Ru need der.

[0004] However, so far, whether the signal generator
Since al the signal output required you can enter by converting set to the reference potential to the signal receiving apparatus apparatus in the transmission line in a reference potential such tinged Do <br/>, the signal of the reference potential Tsu various different to check the operation of the signal receiving apparatus when the inputted lowest <br/> optimal circuit design lines Ukoto it is difficult to the signal receiving apparatus.

[0005]

SUMMARY OF THE INVENTION Output from a signal generator
The case of operating the system while keeping different et a reference potential of the signal inputted to the reference potential and a signal receiving apparatus of a signal is by the interface mismatch between the signal generator and the signal receiving apparatus, the signal receiving It is difficult to accurately reproduce signals on the device
Properly composed addition, the results that exceed the power capacity of the input interface circuit CC an excessive current flows in in the signal receiving apparatus, the characteristic variations or burning accidents due to overheating of the circuit components raw Ji <br/> Rutoitta contingencies There was a danger of a situation.

[0006] Accordingly, it is an object of the present invention is to provide a signal receiving apparatus for testing device capable of converting set the reference potential of the signal inputted to the signal receiving apparatus to the required reference voltage, the signal reception apparatus there is the optimum design to be so as to obtain a row.

[0007]

SUMMARY OF THE INVENTION The present invention provides a signal generator.
S and a signal used in the transmission path between the signal receiving device T
A No. receiving apparatus for testing devices, input impedance matching circuit for matching the waveform of the signal S1 from the signal generator S 2
A signal correction circuit 3 for amplifying the matched signal S3 to a required level; and a reference for converting and setting a reference potential of the signal S4 amplified by the signal correction circuit 3 to a required reference potential.
A reference potential setting circuit 6 including potential setting adjusting means VR1 and VR2, a buffer circuit 7 for amplifying the power of the signal S5 set to the required reference potential, and a waveform of a signal S6 from the buffer circuit 7 Output impedance matching circuit to match
8 and a power supply circuit 9 for supplying a power supply voltage Vcc, Vee to each of the circuits 2, 3 , 6 , 7 are integrally housed in a case C.
The reference potential setting adjusting means VR1 and VR2 are
A test device for a signal receiving device, which is disposed on a C-plane .

[0008]

[Action] The test apparatus for a signal receiving apparatus according to the present invention includes a power supply circuit.
9 and the reference potential setting adjusting means VR1 and VR2.
The signal generator S and the signal receiver are provided on the surface of the case C.
Can be placed independently on the transmission path between
Without modifying the raw device S or the signal receiving device T,
The reference potential of the signal S1 output from the generator S
Can be set and transmitted to the signal receiving device T.
You. In addition, the signal correction circuit 3 having a signal amplitude adjustment function
The characteristics and quality of the input signal S1 and output signal S2 are exactly the same
Since it can be set, it can respond to the input signal S1 of various reference potentials.
In addition to confirming the operating state of the signal receiving device T
Current flowing through the input interface of the signal receiving device T
Since the measured values can be measured, the characteristics of circuit components may fluctuate,
From the signal generator S so that troubles can be prevented beforehand.
Signal receiving device T adapted to the reference potential of output signal S1
The optimal design of the signal receiver and improve the quality of the signal receiver.
Can be made.

[0009]

【Example】 Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS.
This will be described in detail. FIG. 1 shows a test apparatus for a signal receiving apparatus according to the present invention.
FIG. 2 is an explanatory diagram showing a circuit configuration of a main part of FIG.
FIG. 2 is a block diagram illustrating a configuration of a test device for a signal receiving device.
In the embodiment, the input signal is an R, G, B video composite signal.
The signal level is 1.0 Vp-p and the reference potential of the input signal is
Of the pedestal level at the ground level
I will tell. Note that the present invention is limited to this embodiment.
There is no.

[0010] In the figure, reference numeral 1 denotes a test device for a signal receiving device.
SW1 and SW2 are toggle switches.
Switch from the signal generator S to the main part
The signal S1 input to the path 1 is directly transmitted to the signal receiving device T.
Or switching to transmit via main circuit 1
it can. Then, for example, a 75Ω coaxial cable is
The signal S1 input via the transmission line of the
Ω input impedance matching resistor R1
Impedance matching circuit 2 prevents the return loss of signal S1
Matching is performed to minimize shape distortion. Note that the signal S1 is R,
When using multiple transmission lines consisting of G and B,
The main circuit 1 may be provided corresponding to the transmission path.

[0011] Matched by input impedance matching circuit 2
The output signal S3 is composed of the operational amplifier IC1, resistor R2, and trimmer.
A signal correction circuit composed of a variable resistor VR3 consisting of a resistor, etc.
3 and an input signal S1 from a main circuit 1 described later.
The signal level of the output signal S2 is equal in characteristics and quality.
The signal level is corrected and amplified as described above. What
The signal level of the signal 3 at the input terminal of the signal correction circuit 3
The bell is 1.0 Vp-p, and the reference potential is the pedestal level of the image.
Bell is at ground level. Specifically, for example, after
75Ω coaxial cable at the output end of buffer circuit 7
Terminate at 75Ω for impedance matching with line
Need to be done. This In the case of, the output signal S2 is 1.0Vp-p
Signal level at the output end
2.0 Vp-p. Therefore, at the output terminal of the signal correction circuit 3,
Signal level becomes 2.0Vp-p.
Amplifies the signal level 1.0Vp-p at the input terminal twice
Need to be The amplification factor of the operational amplifier IC1 is
It is set by the anti-R2 and the variable resistor VR3.
In order to set the bell to 2.0Vp-p, in the embodiment, R2 is set to 1K
Ω and VR3 are selected as 2KΩ.

[0012] The signal amplified and output by the signal correction circuit 3
S4 is composed of capacitors C1 and C2 and
An AC coupling circuit 4 for AC coupling with the buffer amplifier IC2;
Variable resistors VR1 and VR2 consisting of resistors R3 and R4 and trimmer resistors
The reference potential setting circuit 6 composed of the bias circuit 5
Then, it is converted and set to a desired reference potential. In addition, parallel connection
And the capacitance of the capacitors C1 and C2 constituting the AC coupling circuit 4.
As a value, the composite signal is several tens of Hz of the vertical synchronization signal.
Up to tens of MHz of the dot clock of the video signal
Capacitor C2 is 0.1
μF, capacitor C1 is 330μF to pass low band signals
Has been selected. The output is amplified by the operational amplifier IC1.
The input signal S4 has its DC level cut by the AC coupling circuit 4.
The average value of the composite signal is set to the ground level.
The signal is input to the bias circuit 5 as a signal.
Is superimposed with a DC component. Also, the bias circuit 5
Converts the reference potential of the signal S1 to a desired reference potential
Select the resistance value of resistors R3 and R4 and variable resistors VR1 and VR2.
Alternatively, the reference potential of the signal can be selected. In the example,
Select resistors R3 and R4 as 6.8KΩ and variable resistors VR1 and VR2 as 10KΩ
And the reference potential of the signal S1 is set within a range of + 6V to -6V.
Conversion setting is possible, and the AC connection circuit 4 and the bias circuit 5
A reference potential is converted at the output terminal of the reference potential setting circuit 6.
The specified signal S5 is output.

[0013] The output from the reference potential setting circuit 6
The signal S5 is the signal S1 Signals reduced during transmission
Buffer consisting of a buffer amplifier IC2 that amplifies the signal power
The signal power is amplified by the filter circuit 7 and output as a signal S6.
You. The signal S6 output from the buffer circuit 7 is
Resistance value is input impedance with resistance for impedance matching
An output impedance consisting of the same 75Ω resistor R5 as the matching resistor R1
The reference potential is passed through the inductance matching circuit 8 to the desired reference potential.
To receiver T as output signal S2 converted to
Is done. For buffer amplifier IC2,
If the reference potential of the output signal S2 is + 6V, the termination resistor R
Since the resistance value of 5 is 75Ω, the output terminal of the buffer circuit 7
Requires + 12V. That is, a load of 150Ω (termination resistor R5
75Ω and 75Ω on the load side) need to be driven by + 12V
Therefore, at least 80mA (12V / 150Ω) for buffer amplifier IC2
Current must flow. Therefore, when the load is 150Ω
Assuming that the buffer amplifier IC2 drives about ± 230mA
It is necessary to select a capable amplifier.

[0014] On the other hand, a test device for a signal receiving device is configured.
From a power supply circuit 9 that supplies driving power to each of the circuits 2, 3, 6, and 7
The output power supply voltages Vee and Vcc are
It must be at least twice the reference potential.

[0015] Test apparatus for a signal receiving device having such a configuration
Means that the main circuit 1 is housed integrally in the case C
The variable resistors VR1 and VR2 of the reference potential setting circuit 6 are
The test equipment for the signal receiver was connected to the
In addition to being able to reduce the impact, the reference potential can be easily set.

[0016]

【The invention's effect】 According to the present invention, a signal generator and a signal receiver are provided.
The test equipment for the signal receiving device is installed on the transmission line between the receiving devices,
Convert the reference potential of the signal by the signal generator to the desired potential
It can be easily set and transmitted to the signal receiving device.
Of signal receiving device for input signal of different reference potential
Status can be checked in advance, and the signal receiver can be turned on.
Measurement of the current flowing through the force interface is also possible.
You. As a result, traffic fluctuations in circuit component characteristics and burnout
Configure a signal receiving device to prevent
Optimal design of each circuit becomes possible. In addition, signal receivers
It is also possible to check whether a DC regeneration circuit or the like is necessary.
The quality of the receiving device can be greatly improved. Etc.
Practical effects are extremely large.

[Brief description of the drawings]

FIG. 1 is a main circuit diagram of a test apparatus for a signal receiving apparatus according to the present invention.
Out explanatory view showing the formation.

FIG. 2 1 shows a configuration of a test device for a signal receiving device of the present invention.
It is a block diagram.

[Explanation of symbols]

1 main circuit 2 input impedance matching circuit 3 signal correction circuit 4 AC coupling circuit 5 bias circuit 6 reference potential setting circuit 7 buffer circuit 8 output impedance matching circuit 9 power supply circuit S1, S2 , S3, S4, S5, S6 signal SW1, SW2 selector switch R1, R2, R3, R4, R5, resistor VR1, VR2 variable resistor C1, C2 capacitor IC1 operational amplifier IC2 buffer amplifier Vee, Vcc power supply voltage

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-159805 (JP, A) JP-A-5-175757 (JP, A) JP-A-61-248606 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H03G 1/00-3/18 H03F 1/42-1/56

Claims (1)

(57) [Claims] 1. A test apparatus for a signal receiving device which is arranged and used in a transmission path between a signal generating device S and a signal receiving device T.
I, an input impedance matching circuit 2 for matching the waveform of the signal S1 from the signal generator S, a signal correction circuit 3 for amplifying the signal S3 the matched to the required level, are amplified by the signal correction circuit 3 adjusting hand reference potential setting the reference potential of the signal S4 is converted set to a required reference potential was
A reference potential setting circuit 6 including stages VR1 and VR2; a buffer circuit 7 for amplifying the power of the signal S5 set to the required reference potential; and an output impedance for matching the waveform of the signal S6 from the buffer circuit 7 a matching circuit 8, the power supply voltage Vcc to the circuit 2, 3, 6, 7, a power supply circuit for supplying a Vee
And 9 are integrally accommodated in a case C, and the reference potential
A test apparatus for a signal receiving apparatus , wherein setting adjusting means VR1 and VR2 are disposed on the case C surface .