JP3263919B2 - Satellite broadcast converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a converter for satellite broadcasting and , more particularly, to a satellite with improved isolation characteristics.
The present invention relates to a broadcast converter .

[0002]

2. Description of the Related Art FIG. 12 is a diagram showing an example of a conventional high frequency switching circuit. In this circuit, the output terminal 1 is
The output terminal 2 is connected to the input terminal 1 via the line C1 and to the input terminal 2 via the line C4.
It is connected to input terminal 1 via line C3 and to input terminal 2 via line C2. The output terminal 1 can select the input terminal 1 or the input terminal 2, and the output terminal 2 can select the input terminal 1 or the input terminal 2. The selection of the input terminals 1 and 2 of the output terminals 1 and 2 can be performed. The operation is independent.

FIG. 13 shows an example of a double-sided board used in the conventional example shown in FIG. The line C3 in FIG. 12 is, for example, the conductor 112 provided on one surface of the substrate S in FIG. 13, and the lines C1 and C4 in FIG. 12 are conductors provided on the other surface of the substrate S in FIG. 114 and 116.

A high frequency switch in an intermediate frequency band (1 GHz band) of a conventional satellite broadcast receiving system performs switching by turning on and off a diode.
FIG. 14 shows an example of a high-frequency switching circuit using a conventional diode. The input terminal is connected to the output terminal via a capacitor C and a series circuit of diodes D2, D3 and D4. Capacitor C1 and diode D
2 is grounded via a resistor R1, a voltage V2 is applied via a diode D1, and a voltage V1 is applied to an output terminal. Voltages V1 and V2
, The diodes D2, D3 and D4 are turned on and off to operate as switches.

A filter circuit for coupling a local oscillator and a main line of a low noise converter for satellite broadcast reception is required to have the following characteristics. (1) The load must be stable even in a frequency band other than the local frequency in order to prevent the local oscillator from oscillating at frequencies other than the desired frequency. (2) In order to reduce the signal loss of the main line, the load of the filter viewed from the main line is total reflection in a signal band (a band other than the local frequency).

As a circuit satisfying such characteristics, a filter circuit as shown in FIG. 15 has been widely used. This is because three resistor elements R2, R3 and R3 are provided on the local oscillator side, that is, on the terminal 1 side of the well-known edge-coupled microstrip line bandpass filter circuit.
4 is a circuit provided with a π-type attenuator 200. In this circuit, the load on the local oscillator side is made to look stable by the attenuator 200, and the return loss is twice the amount of attenuation.

[0007]

In the conventional high-frequency switching circuit using the double-sided board shown in FIG. 13, when the output terminal 1 selects the input terminal 2 and the output terminal 2 selects the input terminal 1, the lines C3 and Since C4 intersects, a coupling component between the lines C3 and C4 is generated, so that isolation characteristics are degraded.

In the high-frequency switching circuit shown in FIG. 14, since the isolation characteristics of a single diode are generally not so good, it is necessary to connect many diodes in series in order to improve the isolation characteristics. Therefore, while the circuit scale becomes large,
There has been a problem that losses due to diodes are also accumulated.

The disadvantages of the circuit of FIG. 15 are as follows. (1) In this circuit, if an attempt is made to increase the return loss, the attenuation simply increases. (2) The π-type attenuator usually used as the attenuator 200 requires three resistance elements. (3) The circuit becomes longer by the amount of the attenuator 200,
The degree of freedom of arrangement is small. (4) When no DC flows from the local oscillator,
There is no problem, but when direct current flows, resistance causes loss.

The present invention has been made in view of such circumstances, and a first object of the present invention is to provide a high-frequency circuit having good isolation characteristics.

A second object of the present invention is to enable a switch (ie, a switch) in a high-frequency circuit to be configured with a small circuit scale and low loss.

A third object of the present invention is to provide an edge-coupled microstrip line band-pass filter circuit in which the load seen from one terminal is stable over a wide band and the DC loss due to resistance is eliminated. It is in.

[0013]

SUMMARY OF THE INVENTION A satellite broadcast controller according to the present invention is provided.
The converter is an intermediate frequency signal obtained by converting a horizontally polarized broadcast signal.
The line end where the signal is input is the first input end, and the vertical polarization
Line end where the intermediate frequency signal converted from the broadcast signal is input
Is a second input terminal, and a line terminal connected to the first output unit
Is a first output terminal, and a line terminal connected to the second output unit
Is the second output terminal, and the first input terminal is connected to the first output terminal.
The following line is a first line, and a second input terminal and a second output terminal
The line connecting the force ends is a second line, and the first input terminal
A line connecting the second output terminal is a third line, and a second line
A line connecting the input terminal and the first output terminal is referred to as a fourth line.
And one of the stacked substrates having a ground layer as an intermediate layer
At least on the side of the substrate that is opposite the ground layer.
A third line is provided, and the third line is provided on the surface of the other substrate,
Place at least a fourth track on the side opposite the stratum,
Control in the middle of each of the first, second, third and fourth tracks
An IF amplifier IC that turns on and off when the control voltage changes
Characterized in that was.

[0014]

[0015]

[0016]

[0017]

In the satellite broadcasting converter of the present invention , water
An intermediate frequency signal obtained by converting a broadcast signal with a flat polarization is input.
Line end is the first input end, and the vertically polarized broadcast signal is
The line end to which the converted intermediate frequency signal is input is connected to the second input terminal.
And the line end connected to the first output section is the first end.
The output end is connected to the line end connected to the second output unit.
Connected between the first input terminal and the first output terminal.
The second line is a first line, and a second input terminal and a second output
The line connecting the ends is a second line, and the first input terminal
A line connecting the second output terminal is a third line, and a second line
A line connecting the input end of the first line to the first output line is a fourth line.
Of a stacked substrate having a ground layer as an intermediate layer.
At least on the surface of the other substrate, opposite the ground layer.
A third line is also arranged on the other substrate surface of the substrate.
And at least a fourth line is disposed on a surface opposite to the ground layer.
Each of the first, second, third and fourth lines.
IF amplifier IC that turns on and off by control voltage change during
Be placed . Therefore, the isolation characteristics between the two lines are improved, and the isolation characteristics between the terminals provided at both ends between the lines are also improved.

Further, the number of stages can be reduced as compared with a circuit using a conventional diode, and since the amplifier has a gain, the switch as a whole can have a gain instead of a loss, and furthermore, can be turned on and off. The disturbance of the frequency characteristics at the time is small, and the load on the input / output side can be configured stably.

[0019]

[0020]

FIG. 1 shows the configuration of an embodiment of a high-frequency circuit according to the present invention. The output terminal 1 is connected to the input terminal 1 via the line C1.
Is connected to the input terminal 2 via the line C4, and the output terminal 2 is connected to the input terminal 1 via the line C3.
And to the input terminal 2 via the line C2. The output terminal 1 can select the input terminal 1 or the input terminal 2, and the output terminal 2 can select the input terminal 1 or the input terminal 2. The selection of the input terminals 1 and 2 of the output terminals 1 and 2 can be performed. The operation is independent.
The configuration so far is the same as the conventional example.

A feature of the embodiment of the present invention shown in FIG. 1 is that a ground layer E is provided between two intersecting lines C3 and C4. FIG. 2 shows an example of the multilayer substrate used in the embodiment of FIG. An inner layer, that is, a ground layer E is provided between the substrate S1 and the substrate S2. The line C3 in FIG. 1 is, for example, the conductor 12 provided on one surface of the substrate S1 in FIG.
The lines C1 and C4 in FIG. 1 are the conductors 14 and 16 provided on one surface of the substrate S2 in FIG. That is,
One of the two intersecting lines C3 and C4 is the substrate S1
And the other of the two intersecting lines C3 and C4 is disposed on the surface of the substrate S2 opposite to the ground layer E. Therefore, the isolation characteristics between the lines C3 and C4 can be improved.

When the embodiment of FIGS. 1 and 2 is used for the IF switching circuit 10 of the CS converter as shown in FIG. 11, the isolation of 30 dB or more can be ensured.

The embodiments shown in FIGS. 1 and 2 can be used not only for a CS converter but also for a distribution switch and a tuner using a high-frequency switch, and also for an RF amplifier.

The present invention is not limited to a three-layer substrate,
For example, a high-frequency switch can be formed by increasing the number of ground layers by using a multilayer substrate such as four layers or five layers.

FIG. 3 shows the configuration of an embodiment of a high-frequency circuit using an amplifier as a switch according to the present invention. In this example, the amplifier 20 is configured by an IF amplifier IC. This embodiment is used as an intermediate frequency switch or switch in a satellite broadcast receiving system. The switching of the intermediate frequency is used when receiving vertically polarized waves and horizontally polarized waves in CS broadcasting, and when receiving CS broadcasting and BS broadcasting. And
In this embodiment, for example, the C and B signals can be received by a single converter so that both vertical and horizontal polarizations of the CS broadcast can be received.
It is built in the S converter as an IF (intermediate frequency) switch.

The amplifier 20 is turned on and off by changing the control voltage V1, and operates as a switch. When the amplifier 20 is on, the pass characteristic has a gain.
In this case, care must be taken that | S21 | of amplifier 20 is sufficiently small at the time of ON and OFF, and | S11 | and | at the time of ON and OFF.
S22 | does not fluctuate greatly, but the amplifier 20
Has a gain, the problem can be eliminated by adding an attenuation circuit before and after the amplifier 20.

If an IF amplifier IC is used as the amplifier 20, the isolation is good, the configuration is simple, there is no loss, and there is gain, and the load on the input / output side can be stabilized. In particular, the simplicity of the configuration has a great advantage when configuring a switch, that is, a switch having a large number of input / output terminals.

It is to be noted that a switch using an amplifier according to the embodiment of the present invention shown in FIG. 3 and a conventional switch using a diode as shown in FIG. 14 can be used in combination.

FIG. 4 is a diagram showing an embodiment of an edge-coupled microstrip line band-pass filter circuit according to the present invention. This example is a filter circuit for connecting a local oscillator of a converter for receiving satellite broadcasting and a main line. The filter circuit includes three microstrip lines 32, 34 and 36. The open end A connected to the terminal 1 via the microstrip line 32 is provided with a resistor R having the other end grounded, and a short-circuited end having a length of 1/4 of the wavelength of the pass band frequency. A line L is added. .

In the filter circuit shown in FIG. 4, as described above, a resistor R having the other end grounded is added to the open end A connected to the terminal 1 via the microstrip line. The visible load can be stabilized over a wide frequency band. Further, since a short line L having a length of 1/4 of the wavelength of the pass band frequency is added to the open end A, DC loss due to resistance can be eliminated.

FIG. 5 shows an example of the characteristics of the edge-coupled microstrip line bandpass filter circuit shown in FIG. As shown in FIG. 5, outside the pass band, both terminals 1 and 2 are almost totally reflected, and if a local oscillator is connected to terminal 1, oscillation is likely to occur even at frequencies other than the local frequency.

FIG. 7 shows an example of the characteristics when a resistor R having the other end grounded is added to the open end A connected to the terminal 1 of the edge-coupled microstrip line band-pass filter circuit as shown in FIG. Is shown. As shown in FIG. 8, the reflection on the terminal 1 side is small over a wide band,
The terminal 2 side is almost totally reflected except for a narrow pass band. That is, the load when the filter circuit is viewed from the terminal 1 is stable, and the passage loss increases slightly, but this is not a problematic level. By changing the constant of the resistor R, the optimum point for the passage loss and the return loss viewed from the terminal 1 can be obtained. The circuit shown in FIG. 8 is good in terms of high frequency, but when a bias is applied to the terminal 1, a current flows through the resistor R, causing a DC loss.

FIG. 9 shows an open end A connected to the terminal 1 of the edge-coupled microstrip line band-pass filter circuit via the microstrip line 32 as shown in FIG. 10, ie, as shown in FIG. An example of characteristics when a resistor R whose other end is grounded and a short line L having a quarter of the wavelength of the passband frequency are added is shown. As shown in FIG. 9, in the embodiment of FIG. 4, the DC loss can be prevented, and the return loss seen from the terminal 1 near the DC becomes worse, but a stable load can be obtained in a considerably wide band. This facilitates the design of an oscillator or an amplifier connected to the terminal 1, for example. Further, the condition on the terminal 2 side has not deteriorated.

According to the embodiment shown in FIG. 4, compared to the conventional filter circuit, only one resistor element is required, the size can be reduced, the degree of freedom of arrangement is high, and the DC loss can be reduced. A stable load can be obtained over a wide band. Thus, since the embodiment of FIG. 4 has a stable load, for example, as shown in FIG. 11, if it is used for BPFs (bandpass filters) 48 and 68 after the RF amplifier of the converter, The stability of the RF amplifier is improved.

In the embodiment of FIG. 4, the number of resonators in the filter circuit is one, but the number of resonators can be arbitrarily selected.

In the embodiment of FIG. 4, the short line L
Is connected to the open end, but the connection position can be shifted.

Further, the length of the short line L can be set to a length obtained by adding a length equal to 倍 of the wavelength of the pass band frequency to an integral multiple of 波長 wavelength.

Further, the terminal 2 side has the same configuration, and the return loss can be controlled (however, the loss increases).

FIG. 11 is a high-frequency block diagram showing one configuration example of the CS converter including the embodiment of the present invention shown in FIGS. 1, 3 and 4. The horizontal polarization input is supplied to the BPF 48 via the three-stage RF amplifiers 42, 43 and 44. The output of the BPF 48 is supplied to one input of the mixer 50. The other input of the mixer 50 is supplied with the output of the local oscillator 52 via, for example, the filter circuit 30 constituted by the embodiment of FIG.

The vertically polarized input is a three-stage RF amplifier 62,
It is supplied to the BPF 68 via 63 and 64. B
The output of PF 68 is supplied to one input of mixer 70. The other input of the mixer 70 is supplied with the output of the local oscillator 52 via, for example, the filter circuit 30 constituted by the embodiment of FIG.

The output of the mixer 50 is fed to an IF amplifier 54 and an IF switch 10 which can be implemented by the embodiment of FIGS. 1 and 2 or the embodiment of FIG.
The signal is supplied to the F amplifier 56. The output of the mixer 70 is IF
An amplifier 74 and an IF switch 10 (which can be configured by the embodiment of FIGS. 1 and 2 or the embodiment of FIG. 3) are provided to an IF amplifier 76. The output of the IF amplifier 56 becomes the output of the channel 1, and the output of the IF amplifier 76 becomes the output of the channel 2.

[0042]

According to the converter for satellite broadcasting of the present invention,
For example, an intermediate frequency signal converted from a horizontally polarized broadcast signal is input.
The line end to be input is used as the first input terminal, and the vertically polarized wave is transmitted.
The line end to which the converted intermediate frequency signal is
And the line end connected to the first output unit
And the line end connected to the second output unit is the second end.
And the first input terminal is connected to the first output terminal.
The line is a first line, and the second input terminal and the second output terminal are
The line to be connected is a second line, and the first input terminal and the second line
A line connecting the output terminal is a third line, and a second input terminal
A line connecting the first output terminal and the fourth line is a fourth line,
Of one of the stacked substrates having a ground layer as a layer
At least a third line on a surface opposite the ground layer
Route on the surface of the other substrate of the substrate,
Place at least a fourth track on the opposite side,
A change in the control voltage occurs in each of the third and fourth lines.
Because an IF amplifier IC that turns on and off by
The isolation characteristics between the two lines are improved, the isolation characteristics between the terminals provided at both ends of each line are improved, and the degree of freedom of the circuit configuration can be increased.

[0043] In addition, both to be able to reduce the circuit scale,
Loss can be eliminated, and the load on the input / output side can be configured stably.

[0044]

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of a high-frequency circuit according to the present invention.

FIG. 2 is a perspective view showing an example of a multilayer substrate used in the embodiment of FIG.

FIG. 3 is a diagram showing a configuration of an embodiment of a high-frequency circuit using the amplifier of the present invention as a switch.

FIG. 4 is a diagram showing an embodiment of an edge-coupled microstrip line band-pass filter circuit of the present invention.

FIG. 5 is a diagram illustrating an example of characteristics of the edge-coupled microstrip line band-pass filter circuit shown in FIG. 6;

FIG. 6 is a diagram showing a configuration of an edge-coupled microstrip line bandpass filter circuit itself.

FIG. 7 is a diagram showing an example of characteristics when a resistor whose other end is grounded is added to an open end connected to a terminal 1 of the edge-coupled microstrip line band-pass filter circuit as shown in FIG. .

FIG. 8 is a diagram showing an example of an edge-coupled microstrip line band-pass filter circuit in which a resistor whose other end is grounded is added to an open end connected to a terminal 1;

FIG. 9: As shown in FIG. 10, a resistor whose other end is grounded is added to the open end connected to the terminal 1 of the edge-coupled microstrip line band-pass filter circuit, and 1 / １ ／ of the wavelength of the pass band frequency. FIG. 9 is a characteristic diagram illustrating an example of characteristics when a short line having a length of 4 is added.

FIG. 10 shows that an open end connected to a terminal 1 is added with a resistor whose other end is grounded,
FIG. 4 is a diagram showing an embodiment of an edge-coupled microstrip line bandpass filter circuit of the present invention to which a short line having a length of / 4 is added.

FIG. 11 is a high-frequency block diagram showing one configuration example of a CS converter including the embodiment of the present invention shown in FIGS. 1, 3, and 4;

FIG. 12 is a diagram illustrating an example of a conventional high-frequency switching circuit.

FIG. 13 is a perspective view showing an example of a double-sided board used in the conventional example of FIG.

FIG. 14 is a circuit diagram showing an example of a conventional switch using a diode.

FIG. 15 is a circuit diagram showing an example of a conventional filter circuit for coupling a local oscillator and a main line, that is, an example in which an attenuator is provided on the terminal 1 side (local oscillator side) of an edge-coupled microstrip line band-pass filter circuit. FIG.

[Explanation of symbols]

 Reference Signs List 10 IF switch 20 Amplifier 30 Filter circuit C3, C4 Line L Short circuit R Resistance S1, S2 Substrate

Continuation of the front page (56) References JP-A-4-261022 (JP, A) JP-A-4-373316 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01P 3 / 08 H01P 1/15 H01P 1/203

Claims (1)

(57) [Claims] 1. A method comprising a horizontally polarized wave and a vertically polarized wave.
Received a broadcast signal, and converted the horizontally polarized broadcast signal.
During the conversion of the intermediate frequency signal and the vertically polarized broadcast signal
For satellite broadcasting with two output sections for outputting inter-frequency signals
The converter receives the intermediate frequency signal obtained by converting the horizontally polarized broadcast signal.
The line end to be input is a first input terminal, the line end to which the intermediate frequency signal obtained by converting the vertically polarized broadcast signal is input is a second input terminal, and is connected to a first output unit. A line end is a first output end, a line end connected to a second output portion is a second output end, and a line connecting the first input end and the first output end is
A line connecting the second input terminal and the second output terminal as a first line.
A second line, which connects the first input terminal and the second output terminal,
A third line, a line connecting the second input terminal and the first output terminal;
A fourth line having a ground layer as an intermediate layer;
At least on the surface of the plate opposite the ground layer.
The third line is provided, and the third line is a surface of the other substrate which is opposite to the ground layer.
At least the fourth line is disposed on the pair of surfaces, and each of the first, second, third, and fourth lines is routed.
IF amplifier IC that turns on and off by control voltage change during
A satellite broadcast converter characterized by being arranged.