JPH0261575A - Pulse amplitude detector - Google Patents

Abstract

PURPOSE:To inhibit effect of a jamming pulse by reproducing an envelope using a filter output to make the output as one input of an amplitude comparator. CONSTITUTION:When a train of pair pulse A comprising first and second pulses is inputted at an input terminal 1, a half amplitude detector 2 generates a pulse B indicating generation time of pulses. Then, a pulse couple decoder 4 outputs a decode pulse C indicating a hourly coincidence between a pulse A given a fixed time delay and a non-delay pulse B. An extraction/holding circuit of a video amplitude detector 3 extracts an amplitude data of an input pulse A and holds the amplitude data up to the falling of the subsequent pulse to output a signal D. Then, an amplitude comparator 5 extracts an amplitude of the pulse A synchronizing the pulse C to output a signal E and compares signals D and E to output the smaller one as amplitude display pulse F. An amplitude comparator 6 compares the output F with an output of an envelope reproducer 8 to detect a signal with a smaller amplitude. This enables the elimination of effect of a jamming pulse equal to a pulse interval of the pair pulse.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pulse amplitude detection device, particularly to a pulse amplitude detection device for detecting the envelope of a paired (bare) pulse train used in a TACAN device or the like.

[Prior Art] A TACAN device is an aircraft navigation device that communicates between an aircraft and a fixed ground station, and provides the aircraft with information on the direction and distance of the ground station. The transmission signal of the ground fixed station is transmitted at regular intervals (1
Two pulses (first pulse and second pulse) placed at 2 μs)
This is a train of paired pulses where I iff is a pulse). The interval between these paired pulses is not constant, and on average is approximately 30
0 μS (repetition frequency 3600H2). A ground fixed station uses a transmitting antenna with a heart-shaped directional pattern at a constant speed (1
5RPS). It also sends out an azimuth reference signal at a specific angle of the antenna. Thus, the number of aircraft-mounted receivers is 15.
The azimuth of the aircraft is detected by receiving a pulse amplitude modulated wave modulated by a Hz sine wave and an azimuth reference signal. Note that 135 Hz modulation for accurate direction measurement is superimposed on 15 Hz. Therefore, the on-board receiver needs to detect the envelope of the pulse modulated wave.

Since the duty factor in the paired pulse train is extremely low, the envelope cannot be detected by simply adding the detected video pulses to a smoothing circuit in the on-board receiver. Therefore, the on-board receiver detects the amplitude of at least one of the two pulses constituting the video pulse and holds it until the next pulse pair is received to perform envelope detection.

As a pulse amplitude detection device in a conventional TACAN device, a pulse containing a pair of pulses consisting of a first pulse and a second pulse delayed by a certain period of time from the first pulse is input,
The circuit for detecting the amplitude of the pair of pulses includes a decoding circuit that generates a decoding pulse representing a logical product of the input pulse given a time delay equal to the predetermined time and a non-delayed input pulse; an extraction and holding circuit that extracts and holds the amplitude data until the falling edge of the next input pulse; a circuit that extracts the amplitude of the input pulse synchronized with the decode pulse; an output voltage of the extraction and holding circuit; There is a paired pulse amplitude detection circuit that includes a circuit that compares the output voltage with the amplitude extraction circuit and outputs a voltage corresponding to a smaller voltage (for example, Japanese Patent Publication No. 51-2
Publication No. 3158).

[Problems to be Solved by the Invention] The above-mentioned conventional pulse amplitude detection device does not detect interference pulses superimposed on the first and second pulses of a paired pulse, or 1 from 2nd pulse
If received after 2μs or 12μs before the first pulse
If the interference pulse is received superimposed on the first pulse, the amplitude of the interference pulse becomes the output of the amplitude detector as it is, and the influence of the interference pulse is unavoidable.

In the case of the TACAN device, the output of the envelope detector is filter-linked by 15 Hz and 135 Hz filters for orientation measurements. The present invention enables a pulse amplitude detection device that is less susceptible to interference pulses by regenerating the envelope using this filter output and using this output as another input of the amplitude comparator.

A circuit that extracts the amplitude of a pulse, a circuit that compares the output voltage of the extraction and holding circuit with the output voltage of this amplitude extraction circuit and outputs a voltage corresponding to a smaller voltage, and a circuit that outputs a voltage corresponding to this output voltage and the output of the envelope detection circuit. The circuit includes a circuit that compares a signal obtained by filtering the envelope component from a signal with a signal consisting of a signal whose average level is detected and outputs a voltage corresponding to a smaller voltage, and a circuit that forms an envelope of this output pulse. There is.

[Means for Solving the Problems] The pulse amplitude device of the present invention inputs pulses including a pair of pulses consisting of a first pulse and a second pulse delayed by a certain period of time from the first pulse, and calculates the amplitude of the pair of pulses. a decoder circuit for generating a decoding pulse representing a temporal coincidence time of the input pulse given a time delay equal to the predetermined time and a non-delayed input pulse; and a decoder circuit for detecting amplitude data of the input pulse. The present invention will now be described with reference to the drawings.The present invention will now be described with reference to the drawings.

FIG. 1 shows an envelope detection circuit having a pulse amplitude detection device according to the present invention, and FIG.
The signal symbols A, B, . . . in the figure correspond to the symbols in FIG. 1). A video pulse shown in FIG. 2A is applied to input terminal 1. Here, AI, A2...86 are paired pulses, and 1.・\X is a disturbance pulse. Pair pulse A1
pulse interval (first pulse A1-1 and second pulse A1-
2) is 12 nols, and the same is true for the other paired pulses. Also, the interval between paired pulses (for example, the time interval between pulses A1-1 and A2-1) is approximately 30
Although it is 0 μs, it is shortened for drawing purposes. Although the pulse waveforms constituting the paired pulses are crow waveforms, they are also shown as triangles for convenience of drawing. Jamming pulse AX-1
is superimposed on the second pulse A3-2 of the pair of pulses A5 and AX-2
The following describes the case where the pulse interval of the paired pulse is delayed by 12 μs from A3-2.

The anti-amplitude detector 2 receiving such a pulse train detects the time of the 50% point of the peak value at the leading edge of each pulse, and detects the time of the 50% point of the peak value at the leading edge of each pulse.
Generate pulse B in the figure. Since the manual amplitude point of a pulse is constant regardless of the amplitude of the pulse, this pulse B represents the generation time of each pulse. The video amplitude detector 3 is a circuit that extracts the amplitude data of the input pulse from the terminal 1 and holds the 1F width data until the falling edge of the next input pulse.゜6
~0.9), synthesize, and output the signal.

The pulse pair decoder 4 receives the output B of the hand amplitude detector, and generates a pair detection signal by ANDing a signal to which a time delay equal to the pulse interval (12 μs) of the pair pulse is given and the non-delayed signal B. . The decoder 3 further shapes this paired pulse detection signal into a pulse having a time width equal to the half width (3.degree. 5 .mu.s) of the paired pulse using a monostable multivibrator, and outputs it as a decode pulse C. It is inevitable that a decode pulse will also be generated in response to the interference pulse AX.

The amplitude comparator I includes an analog gate circuit 5a and a comparison circuit 5b.
It consists of. Analog gate circuit 5a passes video pulse A synchronized with decode pulse C to generate signal E. The signal E is the second pulse Al-2, A2-2...
In addition to the signals El, E2, etc., which are gated with the half-width of
It consists of a signal EX obtained by gating the interference pulse with the same time width. The comparison circuit 5b compares the amplitude of the video amplitude detector output and the signal E, and outputs the smaller one as the amplitude display pulse E. The amplitude comparator ■ is a circuit that compares the output F of the amplitude comparator ■ with the output of the envelope regenerator 8 and detects a signal with a small amplitude. This is an envelope detector consisting of a charge/discharge circuit consisting of a parallel circuit of a known capacitor and a switch circuit, and a differentiation circuit, and its output is as shown in FIG. 2I.

The envelope regenerator uses an envelope component filter circuit (TACAN
In the case of the device, it consists of a level averaging circuit for the outputs of 15 Hz and 135 Hz filters), an envelope detector output, and an analog adder circuit for these outputs, and outputs the waveform G shown in FIG.

[Effects of the Invention] As explained above, the present invention uses the circuit shown in FIG. A pulse envelope signal ■ can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an envelope detection circuit having a pulse amplitude detection device according to an embodiment of the present invention, and FIG. 2 is a signal waveform diagram of each part thereof. 1 ・ 2 ・ 3 ・ 4 ・ 5 ・ 6 ・ 7 ・ 8 φ 9 φ input terminal, hand amplitude detector, video amplitude detector, pulse pair decoder, amplitude detector ■, amplitude detector ■, envelope detector, Envelope regenerator, output end.

Claims (1)

[Claims] In a pulse amplitude detection device that inputs a pulse including a pulse pair consisting of a first pulse and a second pulse delayed by a certain period of time from the first pulse, and detects the amplitude of the paired pulse, a time delay equal to the certain period of time is applied. a decoder circuit that generates a decoding pulse representing a time coincidence time between the applied input pulse and a non-delayed input pulse; and a decoder circuit that extracts amplitude data of the input pulse and stores the amplitude data until the falling edge of the next input pulse. An extraction/holding circuit for holding, a circuit for extracting the amplitude of the input pulse synchronized with the decoded pulse, and a voltage corresponding to a smaller voltage by comparing the output voltage of the extraction/holding circuit with the output voltage of the amplitude extraction circuit. a circuit that compares this output voltage with a signal consisting of a signal obtained by filtering the envelope component from the output of the envelope detection circuit and a signal with an average level detected, and outputs a voltage corresponding to the smaller voltage; A pulse amplitude detection device comprising: a circuit for forming an envelope of the output pulse.