JPS5836747B2 - Multipulse detection device in Decca receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for extracting multipulses which are signals for lane identification in a receiver.

In hyperbolic radio navigation, currently known as Detsuka navigation, M
A lane identification signal called P method is transmitted.

In this system, one transmitting station transmits four types of phase-regulated signals during the lane identification signal period.

The receiver receives these signals and adds the main station signal, red station signal, green station signal, and purple station signal to obtain a lane identification signal known as a multipulse. When waves or the like are mixed in, the level of the peak value (lane identification signal) in the added signal a fluctuates, and signals with very close peak value levels are mixed in addition to the regular signals.

For this reason, the method of extracting the peak value by slicing the added signal at a constant level causes errors in lane identification.

The present invention provides a device that performs accurate lane identification by accurately extracting peak values a1, a2, a3 e a4, etc. having a constant period T from the added signals. This will be explained in detail below with reference to the drawings.

In the configuration diagram of FIG. 1 showing one embodiment, the resistance rl”=
r4>r3 t Q + r4>r2 is selected.

The input signal a passes through the capacitor C1, is regenerated as a DC current by the resistor r3, and is connected to the inverting input side (→) of the amplifier Amp via the resistor r4.

The amplifier Amp has high input impedance and low output impedance, and has an amplification degree of about 80 db.

Now, when a1 in Fig. 2 is input, it is inverted and amplified by the amplifier Amp, and the capacitor C2 is a
Charge to the peak value of 1 (inverted and amplified Qi voltage).

During the charging process, the gain of the amplifier AmP is initially 80d.
b, the human power a1 is amplified by 80 db and inverted to charge the capacitor C2 via the diode D1, but the forward resistance r of the diode D1 and the capacitor 02 are short to form an integrating circuit. It is fed back to the input via the resistor r1 after a delay of a certain time constant (forward resistance r x C2 of the diode D1).

This reduces the gain of amplifier Amp to 6db.

For this reason, the signal waveform at point C in Figure 1 is a pulse with a time width from the time when the input signal is amplified and appears at point C until the amplification decreases due to a short time constant determined by r-C2. A large amplitude signal Cll is obtained.

The portion of the signal a1 after this pulse width is amplified by 6 db, phase inverted, and charges the capacitor C2 to its peak value.

After being charged by the input signal a1, the voltage at point b is discharged with a long fixed time constant r2·C2, as shown in FIG. 2b.

Input signal a to the input side of amplifier Amp by input signal a
When the voltage obtained by amplifying and inverting ' by 6db becomes larger than the voltage at point b, that is, when the input signal a' exceeds the feedback voltage, the amplification degree of the time amplifier Amp of rXC2 becomes 80db.
As a result, a pulse output is generated at point C and the capacitor C2 is recharged.

If the output obtained by amplifying and inverting the input signal a' by 6 db is less than the voltage at point b, no output is generated at point C, and signal a is generated at point C.
The peak value portions a1, a2-, a3, a4, . . . are narrow amplitude pulse signals C1, , C21, C3, , C4, . . . determined by the time constant of r-C2. ...
This appears as a lane identification signal.

Furthermore, by changing the value of %r2, the peak value separation ability can be changed.

As described above, the present invention provides a signal a′ obtained by reproducing the added signal a obtained by adding the received signals of each station of the Detsuka navigation signal.
to the input side of an amplifier Amp with a high input impedance and a low output impedance, and a circuit that supplies the output of the amplifier Amp with a short time constant r- including a diode D1.
A circuit that charges an integrator circuit with a long time constant r2·C2 via the C2 circuit, and a circuit that supplies this charged voltage as a negative feedback voltage to the input side of the amplifier Amp via the resistor r1 are provided. At the peak point in the DC reproduction signal a' exceeding the voltage, a short time constant r-
This detection device is characterized by obtaining a lane identification signal with a pulse width determined by the time constant of the C2 circuit, and since detection, amplification, and pulse shaping can be performed with a single amplifier configuration, it is possible to obtain a lane identification signal with a pulse width determined by the time constant of the C2 circuit. It has the advantage that it has a simpler configuration than one that simply performs comparative detection, and has excellent detection ability even when there is little level difference.

Generally, when extracting a lane identification signal, what is the signal a in Figure 2?
Changes in the amplitudes (peak values) of a1*a2, . . . among them change in a temporally long period, and false signals such as a'1 and a'2 are generated due to the mixture of spatial waves.

The purpose of the present invention is to remove fraudulent signals due to the mixture of spatial waves, and does not have the ability to separate when the noise level due to static electricity etc. exceeds the level of input signal a. can be easily removed using a filter or the like, and does not impede the operation of the present invention.

[Brief explanation of the drawing]

The drawings show an embodiment, and FIG. 1 is a block diagram of the main part, and FIG. 2 is a signal waveform diagram.

Claims (1)

[Claims] 1 A device for detecting the peak point in the sum signal obtained by adding the received signals of each station of the Detsuka aviation signal as a lane identification signal, which uses a DC regenerated signal of the sum signal with a high input impedance. a circuit that supplies the input side of an amplifier with low output impedance; a circuit that charges the output of the amplifier to an integrator circuit with a long time constant via a short time constant circuit including a diode; and a circuit for supplying a negative feedback voltage to the input side, and a lane with a pulse width determined by the short time constant is provided to the output side of the amplifier at the peak point in the pre-induced DC reproduction signal exceeding the negative feedback voltage. A detection device characterized by obtaining an identification signal.