JPH09298495A - Signal multiplexer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a peak factor of a multiplex signal in a multiplexer for an amplitude modulation frequency hopping signal and an amplitude modulation quadrature frequency division multiplex(OFDM) signal multiplexer. SOLUTION: In the signal multiplexer, a phase means 21i is provided to each path between an amplitude modulator 2i and a means 8 for forming power, and a phase shift of a phase shift means 21i is controlled in response to an oscillated frequency of a frequency synthesizer 4i so as to reduce a peak factor by a phase control means 22. A frequency hopping control means 7 gives oscillation frequency data to each frequency synthesizer 4i to the phase control means 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal multiplexer for multiplexing frequency hopping signals and an orthogonal frequency division multiplexing (OFDM) signal generator, and more particularly to reduction of the peak factor of the multiplexed signal.

[0002]

2. Description of the Related Art FIG. 10 is a diagram showing a conventional example of an amplitude modulation frequency hopping signal multiplexer. In this conventional device, n (n is an integer of 2 or more) input terminals 1i (i =
1, 2, ..., N), n number of amplitude modulators 2i, reference frequency oscillating means 6, frequency hopping control means 7, power synthesizing means 8 and output terminal 9. n input terminals 1i
Amplitude modulators 2 corresponding to the signals input to the
An amplitude modulation signal is output from i. n amplitude modulators 2
The output signal of i is linearly combined by the power combining means 8 and output to the output terminal 9.

The amplitude modulator 2i comprises a mixer 3i, a frequency synthesizer 4i and a band pass filter (BPF) 5i. The same reference frequency signal is supplied from the reference frequency oscillating means 6 to the n frequency synthesizers 4i. It
The oscillation frequency of the n frequency synthesizers 4i is
By the frequency hopping control means 7, a predetermined time interval T
, A predetermined plurality of frequencies (f1, f2, ..., f
Among n), it is randomly switched to any frequency. Normally, the oscillation frequency of the frequency synthesizer 4i is
The same frequency is used at the same time by the n amplitude modulators 2i to follow a hopping sequence that does not cause collision.
The oscillation frequency can be switched by switching the frequency division ratio of the variable frequency divider that constitutes the frequency synthesizer 4i. The power combining means 8 is composed of a transformer circuit, a hybrid circuit, or the like.

The apparatus shown in FIG. 11 is an orthogonal frequency division multiplex (O
It is a figure which shows the prior art example of the signal multiplexing apparatus used by the FDM) system. In this conventional device, the input terminal 11i (i =
1, 2, ..., N), an inverse discrete Fourier transform unit 13, a frequency transform unit 14, and an output terminal 18. The amplitude data Ci is input from the input terminal 11i to the data input terminal 12i of the inverse discrete Fourier transform means 13, and the time signal obtained by the inverse discrete Fourier transform is output. The time signal output from the inverse discrete Fourier transform means 13 is a signal in which n amplitude modulation waves are frequency division multiplexed, and the frequency difference between the carrier frequencies of the amplitude modulation waves is the input data Ci.
When the time length (symbol period) of Ts is Ts, it is the reciprocal of Ts (1 / Ts). Carrier frequency fk = (k = 1,
, N) is represented by fk = k / Ts.

This OFDM signal is characterized in that the carrier frequencies fk are orthogonal to each other and no mutual interference occurs between the carriers. Generally, the input data Ci is complex number data, but when considering the amplitude modulation OFDM method, the amplitude data of the frequency spectrum of the amplitude modulation wave may be given to the real number part of the input data Ci and the imaginary number part may be zero. Inverse discrete Fourier transform means 13 having a component of carrier frequency fk
The output signal of 1 is frequency-converted into a desired frequency band by the frequency conversion means 14, and the OFDM signal is output from the output terminal 18. The frequency conversion means 14 comprises a mixer 15, a local oscillator 16 and a band pass filter (BPF) 17. The inverse discrete Fourier transform means 13 has, for example, a fast Fourier transform (FFT) processor 13a, a parallel / serial converter (P / S) 13b, and a basic circuit shown in FIG.
It is composed of a D / A converter (DAC) 13c and a low-pass filter (LPF) 13d.

[0006]

Focusing on the envelope power of the multiplexed signal and the OFDM signal obtained by linearly combining the output signals of a plurality of amplitude modulators output from the conventional signal multiplexer, the amplitude power of each amplitude modulator is Due to the condition of the phase depending on the oscillation frequency, it is easy for the modulated signals to have the same instantaneous phase. At the moment when the instantaneous phases of the modulated signals match, the voltages are in-phase combined, which can result in an envelope power peak value (PEP) that significantly exceeds the average power. That is, the peak factor (the ratio of PEP to average power) of the multiplexed signal is significantly increased.

An amplifier is provided at the output of the signal multiplexer,
If a multiplexed signal is to be amplified by the amplifier with low distortion, the required saturation output of the amplifier must be designed to be at least a peak factor times the average power of the multiplexed signal. Therefore, when a multiplexed signal having a large peak factor is generated as described above, it is difficult to downsize the amplifier and save power.

It is an object of the present invention to reduce the peak factor of a multiplexed signal in a signal multiplexing apparatus and an amplitude modulation OFDM signal multiplexing apparatus for multiplexing an amplitude modulation frequency hopping signal.

[0009]

According to the invention of claim 1, n (n is an integer of 2 or more) input terminals, and n amplitude modulators respectively connected to the n input terminals, Power combining means for combining the output signals of the n amplitude modulators and outputting the combined signal to the output terminal, and reference frequency oscillating means for supplying the same reference frequency signal to the local oscillators of each of the n amplitude modulators. And a frequency hopping control means for switching the oscillation frequency of each local oscillator to a predetermined value at a predetermined time interval, in a signal multiplexing device, a shift for changing the phase of each output signal of the n amplitude modulators. Phase means and phase control means for setting the amount of phase shift of the phase shift means to a predetermined value according to the oscillation frequencies of the local oscillators of the n amplitude modulators so that the peak factor of the combined signal becomes small.

According to a second aspect of the present invention, in the apparatus according to the first aspect, the phase shift means is provided in each path between the n amplitude modulators and the power combining means. According to the invention of claim 3, in the device of claim 1, the phase shift means is provided in each path between the reference frequency oscillation means and the n local oscillators. According to a fourth aspect of the invention, in the apparatus according to the first aspect, the phase control means changes the oscillation frequency of the local oscillator of the n amplitude modulators to the n amplitude modulators from the n input terminals. The amount of phase shift of the phase shift means is controlled according to the amplitude of the input signal.

According to the invention of claim 5, n (n is an integer of 2 or more) input terminals, n amplitude modulators having local oscillators having different oscillation frequencies, and n amplitude modulators are provided. Signal multiplexing including power combining means for synthesizing the output signals of 1) and outputting the synthesized signal to the output terminal, and reference frequency oscillating means for supplying the same reference frequency signal to the local oscillators respectively included in the n amplitude modulators. And a connecting means for connecting each of the n input terminals and one of the n amplitude modulators, and the input signal of each input terminal is frequency hopping modulated by the n amplitude modulators. As described above, the path switching control means for switching the connection path in the connection means at a predetermined time interval and the oscillation frequency of the local oscillators of the n amplitude modulators so that the peak factor of the combined signal becomes small. Providing a phase shifting means for changing the phase of the output signals of the amplitude modulator.

According to a sixth aspect of the present invention, in the apparatus according to the fifth aspect, the phase shift means is provided in each path between the n amplitude modulators and the power combining means. According to the invention of claim 7, in the device of claim 5, the phase shift means is provided in each path between the reference frequency oscillation means and the n local oscillators. According to the invention of claim 8, in the device of claim 5, a phase for controlling the amount of phase shift of the phase shift means in accordance with the amplitude of each signal input from the connection means to the n amplitude modulators. A control means is provided.

According to the invention of claim 9, n pieces of input terminals to which the amplitude data of n pieces (n is an integer of 2 or more) of the amplitude-modulated waves to be frequency-division-multiplexed are respectively input, and the n pieces of the input terminals Amplitude modulation OF composed of inverse discrete Fourier transform means having n data input terminals each connected to the input terminal
In a DM system signal multiplexer, the carrier frequency of the amplitude modulated wave is adjusted so as to reduce the peak factor of the multiplexed signal in each path between the n input terminals and the n data input terminals. A phase shifting means for shifting the phase is provided accordingly.

According to a tenth aspect of the present invention, in the signal multiplexing apparatus according to the ninth aspect, connection means is provided for connecting each of the n input terminals and any one of the n phase shift means. , Path switching control means for switching the connection path in the connection means at a predetermined time interval so that the input signal of each input terminal is frequency-hopping modulated by the inverse discrete Fourier transform means.

According to an eleventh aspect of the present invention, in the signal multiplexing apparatus according to the ninth aspect, a phase for controlling the amount of phase shift of the phase shift means according to the amplitude data input to the n input terminals. Control means are provided.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a view showing an embodiment of the invention of claims 1 and 2, and the same members as those in FIG. 10 are designated by the same reference numerals. Further, also in other examples, the same members as those in FIGS. 10 and 11 are denoted by the same reference numerals. In this embodiment, the amplitude modulator 2i
(I = 1, 2, ..., N) and a phase control means 22 for controlling the amount of phase shift of each phase shift means 21i inserted in each path between the power combiner 8 and the power combiner 8. Other than that, it is the same as the embodiment of FIG.

The peak factor of a multitone signal obtained by combining a plurality of tone signals of different frequencies varies widely depending on the combination of the initial phases of the tones.
The peak factor can be reduced by setting the initial phase of each tone to a specific relationship determined according to the frequency of each tone (Narahashi, Nojima: " Suppression effect ", 1
990, Shinbun Gakuen Bunka B-388). The effect of reducing the peak factor by setting the initial phase when the number of multiplexes is changed is compared with the case where the initial phases are matched, as shown in FIG.
FIG. 14 shows an example of envelope waveforms when the number of multiplexes is 16. However, FIG. 13 shows the relationship when each tone has the same amplitude. Further, in FIG. 14, the vertical axis represents the amplitude of each tone, and the horizontal axis represents the normalized value with one cycle of the multitone signal as 1.

When the output signals of the amplitude modulator are combined as shown in FIG. 1, since each tone deviates from the equal amplitude condition,
The peak factor reduction effect deteriorates depending on the amplitude relationship. However, when the local oscillators of the respective amplitude modulators operate by the same reference frequency oscillating means, the phase relationship of the amplitude modulation signals output from the respective amplitude modulators 2i is preserved, so comparison is made when the initial phases match. Then, the peak factor of the multiplexed signal can be significantly reduced.

The amount of phase shift is the carrier frequency of each amplitude modulation signal,
That is, it is set according to the oscillation frequency of each frequency synthesizer 4i. The phase control means 22 receives the oscillation frequency data set in the frequency synthesizer 4i of each amplitude modulator 2i from the frequency hopping control means 7, and controls the phase shift amount of the phase shift means 21i based on the data.

The phase control means 22 includes, for example, a storage element that stores a frequency set value and a phase shift amount as a basic circuit. When a voltage control type element is used as the phase shift means 21i, a D / A converter and a low frequency band are further provided. A pass filter and the like are provided. The phase shifting means 21i can be composed of a circulator, a delay line, a varactor diode, or the like (see Miyauchi, Yamamoto: “Microwave circuit for communication”, pages 314-321, Institute of Electronics and Communication Engineers, 1981), and commercially available products are also used. It is possible.

In the above embodiment, the phase shifting means 21i is
If the phase of the output signal of the amplitude modulator 2i can be adjusted, the same effect can be obtained at any position. Phase shift means 21 is provided on each path between each amplitude modulator 2i and power combining means 8.
The case of inserting i is the invention of claim 2, and the case of inserting the phase shift means 21i in each path between the reference frequency oscillating means 6 and the frequency synthesizer 4i of each amplitude modulator 2i. It is an invention. The latter embodiment is shown in FIG.

FIG. 3 shows an embodiment of the invention of claim 4. As described above, the peak factor reduction effect of the multiplexed signal by the initial phase setting depends on the amplitude relationship of each amplitude modulation signal. The apparatus of FIG. 3 has a phase shift means 21i according to the oscillation frequencies of the n frequency synthesizers 4i provided in FIG.
In place of the phase control means 22 for adjusting the amount of phase shift of, the oscillation frequencies of the n frequency synthesizers 4i and the amplitudes of the signals input from the n input terminals to the n amplitude modulators 2i are set. Phase control means 22 'for controlling the amount of phase shift of the phase shift means 21i according to the value is provided, and other than that is the same as the embodiment of FIG. Compared with the case where the amount of phase shift is set only by the relationship of the oscillation frequency, the peak factor can be significantly reduced.

The phase control means 22 'includes the oscillation frequencies of the local oscillators of the n amplitude modulators and the input signals input to the n amplitude modulators 2i, that is, the amplitude modulation signals output from the amplitude modulators 2i. The phase shift amount is read from the storage element in accordance with the amplitude level of and the control signal for adjusting the phase shift means 21i is output. Here, the amount of phase shift stored in the storage element is set by previously calculating an initial phase relationship such that the PEP of the multiplexed signal is suppressed to about several times the average power for each combination of all input signals. It Further, instead of reading the phase shift amount stored in advance in the storage element,
A configuration may be used in which the amount of phase shift is sequentially calculated and adjusted by a microprocessor or the like according to the signal input to the input terminal 1i.

FIG. 4 shows an embodiment of the invention of claims 5 and 6. This device includes n (n is an integer of 2 or more) input terminals 1i (i = 1, 2, ..., N), connection means 23, path switching control means 24, and n amplitude modulators 2i, n. Phase shifting means 21i, reference frequency oscillating means 6, power combining means 8
And an output terminal 9. A signal is input to the connection means 23 from the n input terminals 1i and is connected to any one of the n amplitude modulators 2i. The connection route in the connection unit 23 is controlled by the route switching control unit 24. The amplitude modulation signals output from the n number of amplitude modulators 2i are respectively sent to the frequency synthesizer 4 by the phase shift means 21i.
After the phase is adjusted according to the oscillation frequency of i, it is linearly combined by the power combining means 8 and output to the output terminal 9.

The amplitude modulator 2i is composed of a mixer 3i, a frequency synthesizer 4i, and a band pass filter (BPF) 5i. The same reference frequency signal is supplied from the reference frequency oscillating means 6 to the n frequency synthesizers 4i. This is the same as the conventional example shown in FIG. The path switching control means 24 randomly switches the connection path for each input terminal 1i at a predetermined time interval T. Here, the frequency synthesizer 4i provided in each amplitude modulator 2i has a predetermined different oscillation frequency (f1, f2, ..., Fn).
To work with. The connection means 23 is provided to realize the same operation as the oscillation frequency switching of the frequency synthesizer 4i controlled by the frequency hopping control means 7 in FIG. 1, and switches the connection path according to the hopping sequence so that there is no collision. . Since the oscillation frequency of each amplitude modulator 2i is not switched, the operation of the frequency synthesizer 4i is stabilized and the device configuration can be simplified as compared with the embodiment of FIG.

In the embodiment of FIG. 4, the phase shift means 21i is
If the phase of the output signal of the amplitude modulator 2i can be adjusted, the same effect can be obtained at any position. Phase shift means 21 is provided on each path between each amplitude modulator 2i and power combining means 8.
The case of inserting i is the invention of claim 6, and the case of inserting the phase shift means 21i in each path between the reference frequency oscillation means 6 and the frequency synthesizer 4i of each amplitude modulator 2i. It is an invention. The latter embodiment is shown in FIG.

FIG. 6 shows an embodiment of the invention of claim 8. This apparatus is provided with a phase control means 25 for controlling the amount of phase shift of the phase shift means 21i according to the amplitudes of the signals input to the n number of amplitude modulators 2i. Is the same as. Each phase shifting means 21i is a frequency synthesizer 4i.
The amount of phase shift is changed according to the oscillation frequency and the amplitude of the input signal of the amplitude modulator 2i. As described in the description of the embodiment of claim 4 shown in FIG. 3, by setting an appropriate initial phase according to the oscillation frequency of the frequency synthesizer and the amplitude relationship of the amplitude modulation signal, only the oscillation frequency shifts. The peak factor can be significantly reduced as compared with the case where the phase amount is set.

The phase control means 25 includes n amplitude modulators 2
According to the input signal input to i, the phase shift amount is read from the storage element and a control signal for adjusting the phase shift means 21i is output. Here, the phase shift amount stored in the storage element is the PE of the multiplexed signal for each of all the input signal combinations.
An initial phase relationship that P can be suppressed to about several times the average power is calculated and set in advance. Further, instead of reading the phase shift amount stored in the storage element in advance, the phase shift amount may be calculated and adjusted by a microprocessor or the like in accordance with a signal input to the input terminal 1i.

FIG. 7 shows an embodiment of the invention of claim 10,
It is the same as the conventional example shown in FIG. 11 except that a phase shift means 31i is provided in the path between the input terminal 11i and the data input terminal 12i of the inverse discrete Fourier transform means 13. The phase shift means 31i complex-multiplies the input data Ci (amplitude data of the amplitude modulation wave) with predetermined initial phase data to generate complex number data Ci ′ to be input to the data input terminal 12i of the inverse discrete Fourier transform means 13. This relationship is
Then, it is expressed by the following equation.

Ci '= {exp (jθi)} × Ci That is, the phase shift means 31i is composed of a complex multiplication circuit.
The phase shift amount θi is set according to the carrier frequency of the amplitude modulation wave. Similar to the description of the embodiment of FIG. 1, the envelope power peak value (or PEP) of the output signal due to the effect of the initial phase setting.
Can be reduced.

FIG. 8 shows an embodiment of the invention of claim 10.
n (n is an integer of 2 or more) input terminals 11i (i = 1, 1)
2, ..., N), the amplitude data of the amplitude-modulated wave is input to the connection means 33, and each of the n pieces of phase shift means 3 is input.
1i. The connection path in the connection means 33 is switched by the path switching control means 34 at a predetermined time interval T (T is an integer multiple of the symbol period Ts). This embodiment is the same as the embodiment of FIG. 7 except that the connection means 33 and the route switching control means 34 are provided. By providing the connecting means 33, a frequency hopping (frequency interleaving) function is provided similarly to the connecting means 23 of the embodiment of FIG.

FIG. 9 shows an embodiment of the invention of claim 11,
In addition to the phase control means 35 for adjusting the amount of phase shift of the phase shift means 31i according to the data Ci input to the phase shift means 31i (i = 1, 2, ..., N), FIG. It is similar to the embodiment. For the same reason as described in the description of the embodiment of claim 8 shown in FIG. 6, comparison is made with a case where the amount of phase shift is fixed by multiplying appropriate initial phase data according to the amplitude modulation data Ci. The peak factor can be reduced.

In the embodiment of FIG. 9, the phase control means 35
According to the data Ci input to the phase shifter 31i,
The phase shift amount is read from the storage element and a control signal for adjusting the phase shift means 31i is output. Here, the phase shift amount stored in the storage element is set by previously calculating an initial phase relationship such that the PEP of the OFDM signal is suppressed to about several times the average power for each combination of all the input data Ci. It Further, instead of reading the phase shift amount stored in the storage element, the phase shift amount may be sequentially calculated and adjusted by a microprocessor or the like according to the input data Ci.

In the device of the above embodiment, the input signal is input in parallel to the n input terminals 1i or 11i. The configuration may be such that serial / parallel conversion means for converting into a signal is provided.

[0035]

As described above, according to the present invention, it is possible to prevent the PEP of the frequency hopping signal multiplexed signal and the orthogonal frequency multiplexed signal from significantly increasing with respect to the average power, and to prevent the signal multiplexed signal from increasing. Is generated, it is possible to reduce the required saturation power of the amplifier and the like provided in the subsequent stage of the device of the present invention.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the invention of claim 1 and claim 2;

FIG. 2 is a block diagram showing an embodiment of the invention of claim 3;

FIG. 3 is a block diagram showing an embodiment of the invention of claim 4;

FIG. 4 is a block diagram showing an embodiment of the invention of claims 5 and 6;

FIG. 5 is a block diagram showing an embodiment of the invention of claim 7;

FIG. 6 is a block diagram showing an embodiment of the invention of claim 8;

FIG. 7 is a block diagram showing an embodiment of the invention of claim 9;

FIG. 8 is a block diagram showing an embodiment of the invention of claim 10;

FIG. 9 is a block diagram showing an embodiment of the invention of claim 11;

FIG. 10 is a block diagram showing a conventional amplitude modulation frequency hopping signal multiplexer.

FIG. 11 is a block diagram showing a conventional amplitude modulation OFDM signal multiplexer.

12 is a block diagram showing a configuration example of an inverse discrete Fourier transform unit in FIG.

FIG. 13 is a graph showing the effect of reducing the peak factor of a multitone signal by setting the initial phase.

FIG. 14 is an envelope waveform diagram of a multitone signal when the number of multiplexing is 16.

Claims (11)

[Claims] 1. N (where n is an integer of 2 or more) input terminals, n amplitude modulators each having a local oscillator connected to the n input terminals, and the n amplitude modulators. Power synthesizing means for synthesizing the output signals of the above and outputting the synthesized signal to the output terminal, reference frequency oscillating means for supplying the same reference frequency signal to the local oscillators of the n amplitude modulators, and the respective local oscillators. A signal multiplexing apparatus comprising frequency hopping control means for switching an oscillation frequency to a predetermined value at predetermined time intervals, and phase shift means for changing the phase of each output signal of the n amplitude modulators, In order to reduce the peak factor of the composite signal, the n
A signal multiplexing apparatus comprising: a phase control unit that controls the amount of phase shift of the phase shift unit according to the oscillation frequency of the local oscillator of each of the amplitude modulators. 2. The signal multiplexing apparatus according to claim 1, wherein the phase shift means is provided in each path between the n amplitude modulators and the power combining means. 3. The signal multiplexing apparatus according to claim 1, wherein the phase shifting means is provided on each path between the reference frequency oscillating means and the local oscillators of the n amplitude modulators. 4. The phase control means according to claim 1, wherein the oscillation frequencies of the local oscillators of the n amplitude modulators and signals input from the n input terminals to the n amplitude modulators. A signal multiplexing device, wherein the phase shift amount of the phase shift means is controlled according to the amplitude of the signal. 5. An n number of amplitude modulators having n number of input terminals (n is an integer of 2 or more), local oscillators of different oscillation frequencies, and output signals of the n number of amplitude modulators are synthesized. And a reference frequency oscillating means for supplying the same reference frequency signal to the local oscillators of the n amplitude modulators. Connecting means for connecting each of the input terminals of each of the n amplitude modulators to any one of the n amplitude modulators, and the input signal of each input terminal is frequency hopping modulated by the n amplitude modulators. The path switching control means for switching the connection path in the connecting means at a predetermined time interval, and the n so as to reduce the peak factor of the combined signal.
A signal multiplexing device comprising: a phase shifter that changes the phase of the output signal of each of the amplitude modulators according to the oscillation frequency of the local oscillator of each of the amplitude modulators. 6. The signal multiplexing apparatus according to claim 5, wherein the phase shift means is provided in each path between the n amplitude modulators and the power combining means. 7. The signal multiplexing apparatus according to claim 5, wherein the phase shifting means is provided on each path between the reference frequency oscillating means and the local oscillators of the n amplitude modulators. 8. The phase control means according to claim 5, further comprising a phase control means for controlling the amount of phase shift of the phase shift means in accordance with the amplitude of each signal input from the connection means to the n amplitude modulators. A signal multiplexing device characterized by: 9. N input terminals to which the amplitude data of n (n is an integer of 2 or more) amplitude modulated waves to be frequency-division-multiplexed are respectively input, and are respectively connected to the n input terminals. Amplitude Modulation Orthogonal Frequency Division Multiplexing (OFD) composed of inverse discrete Fourier transform means having n data input terminals
In the M) type signal multiplexer, the amplitude modulated wave of the amplitude modulated wave is reduced in each path between the n input terminals and the n data input terminals so that the peak factor of the multiplexed signal becomes small. A signal multiplexing device, wherein a phase means for adjusting a phase component of the amplitude data according to a carrier frequency is inserted. 10. The connecting means for connecting each of the n input terminals to any one of the n phase shifting means, and the input signal of each input terminal is the inverse discrete Fourier transform. A signal multiplexing device comprising: a route switching control unit that switches a connection route in the connecting unit at a predetermined time interval so that the frequency hopping modulation is performed by the converting unit. 11. The signal according to claim 9, further comprising phase control means for controlling a phase shift amount of the phase shift means in accordance with amplitude data input to the n input terminals. Multiplexer.