JPH0214633A - Both-polarized wave digital transmission system - Google Patents

Abstract

PURPOSE:To prevent disturbance of synchronizing locking of a demodulator by resetting a waveform equalizer and an equalizer for cross polarized wave interruption elimination in the same timing interruptingly at a fault of a base band signal. CONSTITUTION:If the quality of a reception signal 101 is deteriorated and the carrier synchronization of a demodulator 31 is unlocked, a base band signal 111 becomes faulty. In this case a reset signal 131 is outputted from an out of synchronism detector 51 and a waveform equalizer 11 and a variable coupler being an equalizer for cross polarized wave interference elimination are reset intermittently in the same timing. Thus, the consecution of the state that either of the waveform equalizer 11 or the variable coupler 22 is not reset does not exist and the disturbance of the synchronization locking of the demodulator due to the intermittent reset when the fault of the base band signal 111 is recovered is prevented.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a dual polarization digital transmission system.

[Conventional technology]

In a large-capacity digital transmission system such as a digital microwave transmission system, a transversal filter type waveform equalizer is used to equalize waveform distortion in a transmission path. In addition, in dual-polarization digital transmission systems that transmit separate data signals using two polarizations that are orthogonal to each other at the same frequency, a transversal filter type cross-polarization interference removal method is used to remove cross-polarization interference. An equalizer is used.

The weighting control signals of these waveform equalizers and equalizers for removing cross-polarization interference are based on demodulated received signals, such as base-to-spant signals 52; ” 〉Kura Jt, Ru1, ・If (The quality of Knee No. 1 has deteriorated l,
7. The four carrier wave rules of the 7y4 device are out of order; 6g; h, and the base pantoy + I ”!-No is abnormal, ′:”k:
)・：heavy, 2;-i", the control signal is also abnormal 1i knee,,
it: waveform equalization 2, K> isomorphic type for cross-polarization interference removal kj: 'iF normal (・, 2 is working, /, h: H. Waveform <: ri-type and cross-polarization interference The deterioration of the receiver 8 signal is recovered by creating an equalizer for each use (excluding -) and discharging the equalizer. Synchronous pull-in of the demodulator at the time -7A (,・S1m "k: camp,"
! □Suno,・4o meeting・・Eve) 6・Me, Bess Polarization of the waveform shape and intersection when there is an abnormality in the panto signal]'-interference
Equalizer 4 initial value! J4:! 、S、ノ・
is done j-r, i two (example A', turn ll?;!
:S;"-〆"7'♂": (Publication No. 4). This resetting is performed continuously t,'= and is also performed as "intermittent ξJ-run r," which promotes the demodulator's synchronization pull-in.

'＜-・Spant 'a''
J, ◇ and isomorphic type I for cross-polarization interference removal; ζ intermittent (・
child! J,,t! i:::
The conventional both Tanaba day E, > Tal transmission power formula is +! :,
, , ) are independently performed by the waveform equalizer and the equalizer for crossing 41, 41, 1, 1, 2, and 2.

[Is invention the solution? X+, 1. ．． ．． J', ``Considerable Issues'' Hirabe 1...-l: ・Mi Conventional dual polarization ゛contal transmission system has a waveform equalizer and cross-polarization interference during the violet shape between the spuds. Either one of the equalizers for removal!
J)': TS)Sil,゛(,"I77, The ugly state continues and there is no 1. It's like evil!',!: Call of the field, intermittent rehit 1, °-me(・″-Synchronized pull-in of A restorer 1.
・There is a drawback that interference can be caused by hb' or t-.

The purpose of this article is -1-], Ue!・The state is ゛、
Nari 1'', synchronization pull-in of demodulation gl is disturbed, towa, ru, yu, ub:, -, both bias '6M 'j' digital transmission S
-Providing a ζ system, ``R section 1 cure 1 - flat stage for solving 3】] The dual polarization digital transmission system of the present invention &J1, the same frequency ``ti-Q mutually ζ・S ', 62 mutually intersecting polarized waves) A and C are transmitted using each of them, l,...: two lines...
- Demodulate 1:) of the digital demodulation signals L'''C. (:Jl
,,I: 'it l-ji/suba-zano↑・filter type σ'') waveform equalizer and 9-difference polarization lower interference removal equalizer and waveform χ′ of 0, ′, shape and after the Okawa equalizer and the i-electronic VJI-recording demodulator.
1. Based on the baseband signal described in -6ij. in? iie
The e-type equalizer pawl gripping H control signal and the intersection (1'I
'aQ' f-equalizer for eliminating interference (generates a bow control signal 1-; 5 weights (4-digit control signal generation circuit, 1-, abnormality detection means for detecting abnormalities in the baseband signal) , the weighting control signal 4 of the waveform equalizer and the equalizer for cross-polarization and interference cancellation is generated by the output of the visual detection 1 (4 means).
(゛Wow, line λ7. Same as the predetermined initial value.
Intermittently on Imisogu! ,+(! Knitting means seven knitting means Bizen°ζ2 1, [Example,] Next, the present invention v, 'Let's take a look at the drawings and refer to 1. T:
Please explain.

FIG. 1 does not show one embodiment of the present invention; it is a vine diagram.

Embodiment 1 shown in FIG. & Input l = 57 Subar-Zal filter type waveform equalizer 11.12 and l to combine the output signal of waveform equalizer 11.12 with the output signal of waveform equalizer 12.11
・Lance bar filter type equalizer for cross-polarization interference removal (number A) variable word 8" units 21 and 22, waveform etc.
l<'; Output color of χ11, 12 j...' - Variable coupler 6 unit 72.21o) Demodulator 31 which outputs reliable demodulated baseband signals 111, 112 with combined output signals.
32, a control signal generation circuit 4 for identifying and determining baseband signals 111 and 11.2 and outputting output signals 121 and 122; 1. - h detector p51.52 and out-of-synchronization detector t:) 1. When the synchronization detection signal of +52 is input, it is activated and generates reset signals 131, 132 which are intermittent at a constant cycle.a) Transmitter 61, 62,!
-1 Control control generation circuit 4 [] is base bad signal: 11
], , 11.2 for the output signals 121, 122. Find the correlation between the error and the baseband signals 111 and 112.
The waveform equalizers 11 and 120 are generated by integrating the t and mi correction signals and generating the control signals 1 and 1. The input signals 131 and 132 are In between, the output circuit of the waveform equalizers 11 and 12 resets the initial value 1 = sr, and the control signal generation circuit 40 outputs the baseband signals 112 and 111. j122,12
By integrating the corrected signal outputted after finding the correlation with the 1+, 1, 1, and 5 subband signals 111 and 112, weighting control signals for the variable couplers 21 and 22 are generated and reset. A reset circuit 81.82 is configured to reset the variable coupler 21.22 to the initial value while at least one of the signals 131 and 132 is input.

Received signals 101 and 102 are waveform-equalized by waveform equalizers 11 and 12, cross-polarization interference components are removed by the combined signal from variable coupler 22 and 21, and demodulators 31 and 32
demodulated into baseband signals 111.112 by
The control signal generation circuit 40 performs identification and judgment, and outputs the judgment output signals 121 and 122.

When the quality of the received signal 1010 deteriorates and the carrier synchronization of the demodulator 31 is lost, the baseband signal 111 becomes abnormal.
Baseband signal 111 in which the control signal generation circuit 40 is abnormal
Reset circuit 71.8 based on the correction signal output using
2 continues to output the weighted control signal, the waveform equalizer 1
1. The variable coupler 22 operates abnormally, causing a problem in the synchronization of the demodulator 31 when the received signal 101 recovers from deterioration. However, at this time, the desynchronization detector 51
carrier synchronization is detected, a reset signal 131 is output, and the waveform equalizer 11 and variable coupler 22 are intermittently reset at the same timing. When the waveform equalizer 11 is reset, it outputs the received signal 101 as it is, and when the variable coupler 22 is reset, the output signal to the demodulator 31 is set to 0. Since the waveform equalizer 11 and the variable coupler 22 are intermittently reset at the same timing, either one of the waveform equalizer 11 and the variable coupler 22 will not continue to be unreset. This intermittent reset will not cause a situation in which the synchronization pull-in of the demodulator 31 is hindered. Note that the baseband signal 1 is also used to generate the weighting control signal of the variable coupler 21.
11 is used, the variable coupler 21 is also reset by the reset signal 131. When the carrier synchronization of the demodulator 32 is lost, the waveform equalizer 12 and variable couplers 21 and 22 are similarly reset.

The present invention has been described in detail above with respect to the case where waveform equalization and cross-polarization interference removal are performed in the intermediate frequency band and an abnormality in the baseband signal is detected due to carrier synchronization loss of the demodulator.
The present invention can also be applied to cases in which one or both of waveform equalization and cross-polarization interference cancellation is performed in the baseband band, and in cases in which an abnormality in the baseband signal is detected by abnormal deterioration of the bit error rate of the output signal. In addition, satellite communication systems, etc.
The system as a whole uses both polarized waves, but one receiving station may receive only one polarized wave.

In such cases, a weighting control signal for the variable coupler is obtained by superimposing a perturbation signal on the weighting control signal for the variable coupler without using a baseband signal on the side of a different polarization. In other words, the present invention can be applied even when there is only one demodulator on one polarization side.

〔Effect of the invention〕

As explained above, the present invention enables the waveform equalizer and the cross-polarization interference removal by intermittently resetting the waveform equalizer and the cross-polarization interference removal shape at the same timing when there is an abnormality in the baseband signal. This has the effect of preventing either one of the equalizers from remaining in a state where it is not reset, and preventing synchronization of the demodulator from being disturbed by intermittent resets when the abnormality of the baseband i signal is recovered. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention. 11.12... Waveform equalizer, 21.22...
...Variable coupler, 31.32...Demodulator, 4
0...Control signal generation circuit, 51.52...
...out-of-synchronization detector, 61.62... transmitter,
71, 72, 81.82...Group/reset circuit. Agent Patent Attorney Susumu Uchihara

Claims (1)

[Claims] at least one demodulator that demodulates one of two digitally modulated signals transmitted using two mutually orthogonal polarized waves at the same frequency and outputs a baseband signal; a transversal filter type waveform equalizer and a cross-polarization interference removal equalizer provided after the waveform equalizer and the cross-polarization interference removal equalizer provided after the demodulator; a weighting control signal generation circuit that generates a weighting control signal for the waveform equalizer and a weighting control signal for the cross-polarization interference removal equalizer based on a baseband signal; and detecting an abnormality in the baseband signal. an abnormality detection means; and a reset means for intermittently resetting the weighting control signals of the waveform equalizer and the cross-polarization interference removal equalizer to predetermined initial values at the same timing using the output of the abnormality detection means. A dual polarization digital transmission system characterized by: