JPH04175013A - Transmitter-receiver for satellite communication - Google Patents

Abstract

PURPOSE:To prevent adverse effect onto other station in advance by stopping the transmission of a signal data automatically till an oscillation output is made stable. CONSTITUTION:At application of power to a crystal oscillator 131, much more current flows than that in the steady-state to warm up an internal heater and power consumption is increased. When a level difference across a low resistance resistor 14 inserted between a power supply 5 and the crystal oscillator 131 is detected and it is large, a comparator 20 judges it that a heater current is unstable and the frequency is also unstable and turns off a switch 16. Thus, the output of a data signal subject to frequency conversion from a conversion section 12 to an amplifier 17 is blocked. When the level difference is smaller, the comparator 20 judges it that the heater current is made stable and the frequency is stable and turns on the switch 16. As a result, since the transmission of the data signal subject to frequency conversion is allowed, the transmission is implemented with a stable oscillation output and adverse effect onto other station is prevented in advance.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a satellite communication transmitting/receiving system that uses a highly stable crystal oscillator that is temperature-compensated by a heater as a local oscillator or a reference for the local oscillator. It is related to the device.

(Prior Art) Recently, various communication systems using communication satellites have been considered. For example, if a plurality of ground stations are connected to a communication satellite and a data signal is sent out from any ground station,
There is a satellite communication system in which this data signal is relayed by a communication satellite repeater and transmitted to other ground stations.

By the way, some ground stations used in such satellite communication systems have a configuration as shown in FIG. 3 as a transmitter/receiver for satellite communication.

In other words, in such a satellite communication transmitting/receiving device, when a data signal is input to the input terminal 1, this data signal is sent to the frequency converter 2, where it is converted to a local oscillator consisting of a crystal oscillator 31 and a frequency synthesizer 32. The frequency is converted according to the local oscillation output of the signal, and the signal is outputted from an output terminal 5 through an amplifier 4.

In this case, the transmitter/receiver for satellite communication that performs 5CPC communication is 45K in the 30GHz frequency band.
Channels are set at Hz intervals, and the frequency conversion section required for local oscillation is less than 1.5X10-'. To achieve such highly stable local oscillation, the crystal oscillator 31 is equipped with a heater (not shown). A highly stable crystal oscillator that is temperature compensated by The highly stable crystal oscillator 31 is connected to a power source 6, and when the power source 6 is turned on, it starts up while warming the internal heater and generates a predetermined oscillation output.

(Problem to be solved by the invention) However, such a highly stable crystal oscillator 31 is
When the internal heater is turned on, it starts up while warming the internal heater.
It takes time for the heater current to stabilize and the frequency to stabilize, and the rise characteristics of the output are as shown in FIG.

Therefore, the oscillation output will not be stable until a predetermined time has elapsed after the power is turned on, and if a transmission operation is performed in this state, the data signal will become unstable and may have a negative impact on other stations. There was an inconvenience.

The present invention has been made in view of the above circumstances, and is for use in satellite communications, which can automatically stop transmitting signal data until the oscillation output is stabilized, and can prevent adverse effects on other stations. The purpose is to provide a transmitting and receiving device.

[Structure of the Invention] (Means for Solving the Problems) The satellite communication transmitting/receiving device of the present invention uses a highly stable crystal oscillator that is temperature compensated by a heater as a local oscillator or a reference for the local oscillator. Therefore, when the crystal oscillator is powered on, more current flows than in normal operation to warm up the internal heater, which increases power consumption. Therefore, this change in power consumption is detected, and from this detection result, the power consumption of the crystal oscillator is determined. When it is detected that the crystal oscillator is large, the data signal transmission operation is stopped, and when it is detected that the power consumption of the crystal oscillator has stabilized, the data signal transmission operation is permitted.

(Function) As a result, according to the present invention, the power consumption is stabilized by focusing on the fact that when the power is turned on, the crystal oscillator warms the internal heater, so more current flows than in a steady state, and the power consumption increases. Since the data signal transmission operation can be stopped until the heater current stabilizes and the frequency becomes stable, the transmission operation can be started, making it possible to always achieve stable data signal transmission. .

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the circuit configuration of the same embodiment. In the figure, 11 is an input terminal, and a data signal input to this input terminal 11 is sent to a frequency conversion section 12. A crystal oscillator 13 is connected to this frequency converter 12 . The crystal oscillator 13 generates a predetermined local oscillation output, and provides this local oscillation output to the frequency conversion section 12.

In this case, the crystal oscillator 13 is a highly stable crystal oscillator 13 which has an internal heater (not shown) and whose temperature is compensated by the internal heater.

A power supply 15 is connected to this crystal oscillator 13 via a resistor 14 having a small resistance value.

In this case, when the power supply 15 is turned on, the crystal oscillator 13 simultaneously supplies power to an oscillation circuit (not shown) and also supplies heater current to the internal heater.

The crystal oscillator 13 constitutes a local oscillator together with a frequency synthesizer 131, and the oscillation output here is provided to the frequency converter 12. The data signal frequency-converted by the frequency converter 12 is sent to the amplifier 17 via the switch 16 and output from the output terminal 18.

The switch 16 is capable of blocking the output of the data signal frequency-converted by the frequency converter 12, and its opening/closing operation is controlled by a comparison output of a comparator 20, which will be described later.

A differential amplifier 19 is connected to both ends of a resistor 14 connected between a crystal oscillator 13 and a power supply 15.

This differential amplifier 19 generates an output according to the difference in voltage appearing across the resistor 14.

In this case, when the power F115 is turned on, more current flows in the crystal oscillator 13 than in the normal state to warm up the internal heater, and the power consumption increases.As shown in FIG. It takes a certain amount of time for IX to stabilize. As a result, a predetermined potential does not appear on the crystal oscillator 13 side of the resistor 14 until the current consumption of the crystal oscillator 13 stabilizes, and a potential difference appears between both ends of the resistor 14 during this time.

Then, the differential output of the differential amplifier 19 is transmitted to the comparator 2.
0 to one input terminal. This comparator 20
A reference voltage 21 is applied to the other input terminal of the . Here, when the differential output of the differential amplifier 19 is larger than the reference voltage 21, the comparator 20 operates to open the switch 16 using the comparison output, and when the differential output is smaller than the reference voltage 21, the comparator 20 closes the switch 16 using the comparison output. I'm trying to get it to work.

Next, the operation of the embodiment configured as above will be explained.

Now, when the power supply 15 is turned on, the power supply 15 is immediately stabilized at a predetermined potential, whereas the crystal oscillator 13 takes a predetermined period of time from the time the power is turned on until the current consumption IX stabilizes, as shown in FIG. It takes. In other words, a large current consumption IX continues to flow for about 10 minutes after the power is turned on to warm up the internal heater. As a result, the potential of the resistor 14 on the crystal oscillator 13 side becomes high, and a large potential difference occurs between both ends of the resistor 14.

The potential difference between both ends of this resistor 14 is determined by the differential amplifier 19.
given to. Then, the differential amplifier 19 generates a differential output corresponding to the potential difference across the resistor 14 at this time, and this output is sent to one input terminal of the comparator 20.

A reference voltage 21 is applied to the other input terminal of the comparator 20.

Comparator 20 compares the differential output from one differential amplifier with reference voltage 21 . In this case, the differential amplifier 19
The differential output from the resistor 14 corresponds to the large potential difference across the resistor 14 and is larger than the reference voltage 21, so the comparator 20 generates a corresponding comparison force, and this comparison output opens the switch 16. be done.

As a result, the output side circuit of the frequency converter 12 is opened, and the output of the data signal frequency-converted by the frequency converter 12 to the amplifier 17 is blocked.

After that, a predetermined period of time has passed since the power was turned on, and the crystal oscillator 1
When the current consumption lx at 3 becomes stable, the resistance 14
The potential on the crystal oscillator 13 side gradually decreases, and the resistance 1
4 The potential difference between both ends also becomes smaller.

Then, the differential output of the differential amplifier 19 also changes to a smaller value in accordance with the potential difference across the resistor 14, and this output is compared with the reference voltage 21 by the comparator 20.

In this case, the differential output from the differential amplifier 19 is
It is small according to the potential difference between both ends, and is also small compared to the reference voltage 21, so from the comparator 20,
A comparison output corresponding to this is generated, and this comparison output in turn closes the switch 16.

As a result, the output side circuit of the frequency converter 12 is closed, and the data signal frequency-converted by the frequency converter 12 is
It passes through the amplifier 17 and is output from the output terminal 18.

Therefore, in this way, when the crystal oscillator 13 is powered on, more current flows to warm up the internal heater than during normal operation, which increases power consumption. Detects the potential difference between both ends of the low resistance 14, and if this potential difference is large, it determines that the heater current is still unstable and the frequency is unstable, and stops transmitting the data signal.After that, when the potential difference becomes smaller, Since the heater current is determined to be stable and the frequency is also stable, data signal transmission is permitted, so the transmission operation can be performed from a state where the oscillation output is stable, and a stable data signal can be transmitted. can be transmitted, and it is possible to prevent any adverse effects on other stations.

Note that the present invention is not limited to the above-mentioned embodiments, but can be implemented with appropriate modifications within the scope without changing the gist.

For example, in the embodiment described above, the switch 16 is inserted between the frequency converter 12 and the amplifier 17 to block the output of the frequency converter 12, but this switch 16 is inserted between the frequency converter 12 and the highly stable crystal oscillator. 13, the same effect as described above can be expected. Furthermore, although the switch 16 is used in the embodiment described above, an attenuator may be used instead. Furthermore, in the embodiment described above, the reduction in power consumption when the highly stable crystal oscillator 13 is powered on is detected by the potential difference across the low resistor 14 inserted between the power source 15 and the magnitude of this potential difference. However, this is not limited to this, and when the crystal oscillator is turned on, more current flows than during normal operation to warm up the internal heater, which increases power consumption. The magnitude of this power consumption is detected by other means, and when it is detected that the power consumption of the crystal oscillator is large from this detection result, the data signal transmission operation is stopped and the power consumption of the crystal oscillator is stabilized. The configuration may be such that when it is detected that the data signal has been transmitted, the data signal transmission operation is permitted.

[Effects of the Invention] The transmitting/receiving device for satellite communication of the present invention uses a highly stable crystal oscillator whose temperature is compensated by a heater as a local oscillator or a reference for the local oscillator, and when the power of the crystal oscillator is turned on, To warm up the internal heater, more current flows than during normal operation, increasing power consumption. Therefore, this change in power consumption is detected, and when it is detected from this detection result that the power consumption of the crystal oscillator is large, the data signal is When the transmission operation is stopped and it is detected that the power consumption of the crystal oscillator is stabilized, the transmission operation of the data signal is permitted.
Focusing on the fact that when the power is turned on, the crystal oscillator warms the internal heater, which causes more current to flow than in normal conditions, increasing power consumption, we have decided to stop the data signal transmission operation until this power consumption stabilizes. Therefore, it is possible to start the transmission operation only after the heater current in the crystal oscillator has stabilized and the frequency has stabilized, making it possible to always achieve stable data signal transmission and avoid adverse effects on other stations. Things like this can also be prevented.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram of an embodiment of the present invention, and FIG. 2 is a circuit diagram of an embodiment of the present invention.
A diagram showing how the current consumption of the highly stable crystal oscillator used in the same embodiment changes after power-on; FIG. 3 is a circuit configuration diagram showing an example of a conventional transmitter/receiver; and FIG. FIG. 2 is a diagram showing the rise characteristics of a highly stable crystal oscillator. 12... Frequency converter, 13... Crystal oscillator, 14
...Resistance, 15...Power supply, 16...Switch, 1
7... Amplifier, 19... Differential amplifier, 2o... Comparator, 21... Reference voltage. Applicant's agent Patent attorney Takehiko Suzue 1- Time report (minutes) @ 2 Figure

Claims (1)

[Scope of Claims] In a satellite communication transmitting/receiving device that uses a highly stable crystal oscillator whose temperature is compensated by a heater as a local oscillator or a reference for the local oscillator, a change in power consumption of the crystal oscillator as the power is turned on is detected. a detection means for detecting that the power consumption of the crystal oscillator is large; when the detection means detects that the power consumption of the crystal oscillator is large, the transmission operation of the data signal is stopped; and when it is detected that the power consumption of the crystal oscillator has become stable, the transmission operation of the data signal is stopped. 1. A transmitting/receiving device for satellite communication, comprising a control means for permitting permission.