JPH04169882A - Apparatus for detecting pair-pulse amplitude - Google Patents

Abstract

PURPOSE:To detect correctly the amplitude of a pair of pulses against equal interfering pulses by controlling a detecting range of amplitude-indicating pulses using two regeneration envelopes to set up the maximum and minimum permissible limits on use formed for envelopes to be regenerated. CONSTITUTION:An amplitude comparator 8 compares an amplitude-indicating pulse F with the first output G receiving from an envelope regenerator 7 and outputs only the pulse of lower amplitude than it of the output G. The output G is formed by the regenerator 7 in the same way as the second output J. The regenerator 7 receives the envelope output which an envelope detector 6 outputs, and regenerates to output the two envelope outputs of the output G which is the envelope to indicate the maximum permissible value on use corresponding to the mean level and the output J which is the envelope to indicate the minimum permissible value on use. An amplitude comparator 9 compares the output G with the output J and outputs only an output H of smaller amplitude of the output J. The envelope detector 6 transmits the obtained envelope output to an output terminal and the regenerator 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a paired pulse amplitude detection device, particularly a pair used in a TACAN device [Prior Art] The Takan device, which is operated in the United States, is an aircraft navigation device that supports aircraft navigation by communicating with the aircraft and a fixed ground station, and provides direction and distance information to the aircraft using signals transmitted from the ground station. A transmission signal from a terrestrial fixed station consists of a plurality of pairs of pulses, each consisting of two pulses (a first pulse and a second pulse) arranged at regular intervals (12 μs). The interval between paired pulses is not constant, and on average is approximately 300 μs (repetition frequency: 3.80 μs).
0Hz).

The terrestrial fixed station rotates a transmitting antenna with a heart-shaped directional pattern at a constant speed (15 RPS). Also.

Send out an azimuth reference at a specific angle of the antenna. thus,
A receiver mounted on an aircraft receives a pulse amplitude modulated wave whose amplitude is modulated with a 15 Hz sine wave and an azimuth reference signal, and detects the azimuth of the aircraft. In addition.

A 135 Hz amplitude modulation for orientation measurement is superimposed on 15 Hz. The onboard receiver detects the envelope of the pulse modulated wave thus formed to detect the orientation.

Since the duty factor in the above-mentioned paired pulse train is extremely low, envelope detection cannot be performed in a dual receiver by simply adding the detected paired video pulses to a smoothing circuit.

Therefore, the single-machine receiver detects the amplitude of one of the two pulses constituting the video pulse and holds it until the ninth pulse pair is received to perform envelope detection.

As a paired pulse amplitude detection device in a conventional Takan device, a pulse including a paired pulse consisting of a first pulse and a second pulse delayed by a certain period of time from the first pulse is input,
A decoding circuit generates a decoding pulse representing the logical product of an input pulse given a time delay equal to the above-mentioned fixed time and a non-delayed input pulse, and a decoding circuit that extracts amplitude data of the input pulse and calculates the amplitude data of the input pulse until the falling edge of the next input pulse. The extraction and holding circuit that holds the extracted amplitude data, the amplitude extraction circuit that extracts the amplitude of the input pulse synchronized with the decoded pulse mentioned above, and the output voltage of the extraction and holding circuit and the output voltage of the amplitude extraction circuit are compared. There is a paired pulse amplitude detection circuit including a circuit that outputs only a signal having a small voltage (for example, Japanese Patent Publication No. 51-23158).

[Problem to be solved by the invention]

The above-mentioned conventional pulse amplitude detection circuit detects noise or gt interference pulses when the first and second pulses of a pair of pulses are received in a weighted manner, or when the pulse amplitude is superimposed on the second pulse and the second pulse is received.
If the pulse is received 12 μs after the first pulse, or if it is received 12 μs before the first pulse and superimposed on the first pulse, the amplitude of the interfering pulse becomes the output of the amplitude detector, and the influence of the interfering pulse is unavoidable. There are drawbacks.

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the above-mentioned drawbacks and to provide a pulse amplitude detection device that is less susceptible to interference pulses and noise pulses.

[Means to solve the problem]

The device of the present invention is a Takan device that inputs a pulse train 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 pulse train that has a predetermined amplitude modulation. In the paired pulse amplitude detection device at the upper station, a decoded pulse is obtained by detecting the paired pulse by obtaining time coincidence between the input pulse given a time delay equal to the certain time and the input pulse not given the time delay. a decoder circuit for outputting, an extraction and holding circuit for extracting amplitude data of an input pulse and holding the amplitude data until the falling edge of the next input pulse, and an extraction and holding circuit for extracting the amplitude of the input pulse synchronized with the decoded pulse. An amplitude comparator that outputs a signal with a smaller amplitude compared to the output of (
and an envelope detector for detecting the envelope of the pulse train formed by the paired pulses based on the output of the amplitude comparator (1).

From the output of this envelope detector, a first output indicating the operationally acceptable maximum value of the envelope and a second output indicating the operationally acceptable minimum value are generated and output in accordance with the average level of the envelope. an envelope regenerator that outputs the first envelope regenerator;
an amplitude comparator (2) that compares the output of the first output with the output of the amplitude comparator (1) and outputs only the output having a smaller amplitude than the first output; and the output of the envelope regenerator. An amplitude comparator that compares the second output with the output of the amplitude comparator (2), outputs only the one having a larger amplitude than the second output, and supplies the output as an input to the envelope detector. (3).

Further, in the pulse amplitude detection device of the present invention, the output of the decoded pulse in the decoder circuit is as follows.

The configuration is such that the pulse is generated at the timing of the half width at the leading edge of the input pulse.

〔Example〕

Next, nine aspects of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention.

The embodiment shown in FIG. 1 takes the case of an airborne station of the Takan device as an example, and includes a decoder circuit 1 that decodes pulse pairs from input pulses including paired pulse trains received from an input terminal and outputs decoded pulses, and an input pulse train. an extraction and holding circuit 4 that extracts the amplitude data of and holds it until the falling edge of the next input pulse;
An amplitude comparator (1) 5 that extracts the amplitude of an input pulse synchronized with a decoded pulse, compares the outputs of the extraction and holding circuit 4, and outputs only those having a smaller amplitude; and an amplitude comparator (1)
an envelope detector 6 for detecting the envelope of the pulse train of the paired pulses based on the output of the pulse generator 5; an envelope regenerator 7 that generates and outputs a first output representing a first output and a second output representing an operationally acceptable minimum value; 1) an amplitude comparator (2) 8 which compares the output of the first output with the first output and outputs an output having a smaller amplitude than the first output;

The second output of the envelope regenerator 7 and the amplitude comparator (2
) 9, and outputs only the one having a larger amplitude than the second output, and supplies it as an input to the envelope detector 6. The middle decoder circuit 1, the extraction and holding circuit 4, and the amplitude comparator (
1) 5 is the same as the one installed in normal Takan device airborne stations.

Next, the operation of the two embodiments will be explained.

FIG. 2 is a diagram of signal waveforms at various parts of the embodiment shown in FIG.
The waveforms corresponding to the symbols A, B...K in the figure are shown, respectively. The operation of the embodiment shown in FIG. 1 will be explained below with reference to FIG. 2.

A video pulse shown in FIG. 2A is applied to the input terminal. Here, A11A21...A6 are normal paired pulses, INx is noise, and AX is an interference pulse. The pulse interval of the pair of pulses At (the time interval between the first pulse A1-1 and the second pulse Al-2) is normally 12 μs, and the same is true for the other pulse pairs. Also, the interval between paired pulses (for example, the time interval between pulses AI- and A2-1)
is approximately 300 μs, but it is shortened for illustration purposes. Although the pulse waveforms constituting the pair of pulses are Gaussian waveforms, they are shown as triangles for convenience of drawing. In FIG. 2, the noise pulse Nx is superimposed on the second pulse A3-2 of the paired pulse A5 at 12 μs before the paired pulse A3, and the interference pulse A x -s is superimposed on the second pulse A3-2 of the paired pulse A5. The following describes the case where the pulse interval is delayed by 12 μs.

The decoder circuit 1 consists of a hand amplitude detector 2 and a pulse pair decoder 3, and the hand amplitude detector 2 receives the input pulse train of video pulses shown in FIG. 2A at the 50% point of the peak value at the leading edge of each pulse. The pulse shown in FIG. 2B is generated by detecting the time of . Since the half-amplitude point of a pulse is constant regardless of the amplitude of the pulse, this pulse B represents the time at which each pulse occurs.

Extraction/holding circuit 4c for detecting the amplitude of input pulse A is a circuit that extracts the amplitude data of input pulse A and maintains the amplitude data until the fall of the primary input pulse. The signals are multiplied by a smaller coefficient (0.6 to 0.9) and combined to output a signal.

The pulse pair decoder 3 receives the output pulse B of the half-amplitude detector, and outputs a signal with a time delay equal to the pulse interval (12 μs) of the paired pulse, and a pulse B which is a non-delayed signal.
A signal is generated as a pair of pulse detection signals by performing a logical product with . The pulse pair decoder 3 further shapes this paired pulse detection signal into a pulse with a time width that is equal to the half width (3.5 μs) of the paired pulse using a monostable multivibrator.

Output as decode pulse C. In this case, the noise Nx
, it is unavoidable that a decode pulse is generated also for the interference pulse Ax.

The amplitude comparator (1) 5 consists of an analog gate circuit 5a and a comparison circuit 5b. The analog gate circuit 5a inputs an input pulse A synchronized with the decode pulse C and outputs a signal E.
occurs. The signal E is the second pulse AX-2r of the paired pulse.
It consists of a signal EX>E2g . . . which is obtained by gated A2-2 + . . . with its half-width, and a signal EX-1tE The comparison circuit 5b compares the amplitude of the signal output from the extraction/holding circuit 4 and the signal E, and outputs the smaller one as the amplitude display pulse F.

The amplitude comparator (2) 8 compares the amplitude display pulse F with the first output G received from the envelope regenerator 7, and outputs only the one having a lower amplitude than the first output G. The first output G, like the second output J, is generated by the envelope regenerator 7.

The envelope regenerator 7 includes a filter that receives an envelope output from an envelope detector 6 (described later) and outputs 15 Hz and 135 Hz components, and a level filter that outputs an average level of the envelope output indicated by a DC level. It has an averaging circuit and an analog addition circuit that adds the outputs of these filters and the average level, and a first output G that is an envelope indicating the maximum allowable value for operation corresponding to the average level in each of these circuits; Two envelope outputs of the second output J, which is an envelope indicating the minimum allowable value for operation, are reproduced and output. That is, the desired regular pulse pairs will be distributed between the first output G and the second output J. The amplitude comparator (2) 8 compares the amplitude display pulse F and the first output G, and outputs only the amplitude display pulse F having a smaller amplitude than the first output as an output H.

The amplitude comparator (3) 9 compares the output G and the second output J, and outputs only the output H having a smaller amplitude than the second output J. Thus, from the amplitude comparison circuit (3) 9, only a signal having an amplitude smaller than the first output G and larger than the second output J shown in FIG. 2 is supplied to the envelope detector 6. Become. Through such processing, even if there is an interfering pulse or the like that is equal to the desired paired pulse interval, the envelope detector 6 uses the output K representing the accurate amplitude of the paired pulse as an amplitude display pulse.
can be supplied to

The envelope detector 6 is an envelope detector composed of a charge/discharge circuit formed as a well-known parallel circuit of a capacitor and a switch circuit, and a differentiation circuit, and connects the envelope output obtained in this way to the output terminal. The signal is sent to the line regenerator 7.

In this way, accurate amplitude detection of the paired pulses can be achieved even if there are interfering pulses with equal spacing between the paired pulses.

〔Effect of the invention〕

As explained above, the present invention controls the detection range of the amplitude display pulse using two regenerated envelopes that are formed by regenerating the envelope and sets an operationally acceptable upper limit and an allowable lower limit. Even if there are interfering pulses with equal intervals, the amplitude of paired pulses can be detected accurately.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a signal waveform diagram of each part of the embodiment of FIG. 1... Decoder circuit 1, 2... Half amplitude detector, 3...
...Pulse pair decoder, 4...Extraction and holding circuit, 5...
・Amplitude detector (1), 6... Envelope detector, 7...
Envelope regenerator, 8...amplitude detector (2), 9...amplitude comparator (3).

Claims (1)

[Claims] 1. A Takan device that inputs a pulse train 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 pulse train that has a predetermined amplitude modulation. A decoded pulse in which the paired pulse amplitude detection device of the airborne station detects the paired pulse by obtaining time coincidence between the input pulse given a time delay equal to the predetermined time and the input pulse not given the time delay. a decoder circuit that outputs the amplitude data of the input pulse and holds the amplitude data until the falling edge of the next input pulse; An amplitude comparator (1) that outputs a signal having a smaller amplitude than the output of the circuit; and an envelope detection device that detects the envelope of the pulse train of the paired pulses based on the output of the amplitude comparator (1). a first output indicating an operationally acceptable maximum value of the envelope and a second output indicating an operationally acceptable minimum value corresponding to the average level of the envelope from the output of the envelope detector. an envelope regenerator that outputs a an amplitude comparator (2) that outputs only the amplitude
and the output of the amplitude comparator (2), and outputs only the output having a larger amplitude than the second output, and supplies the output as an input to the envelope detector.
) A paired pulse amplitude detection device characterized by comprising: 2. A paired pulse amplitude detection device, wherein the output of the decoded pulse in the decoder circuit is performed by a pulse generated at a timing of a half-width time position at the leading edge of the input pulse.