JPS6066546A - Synchronous general optimum receiver of noise following-up type - Google Patents

Abstract

PURPOSE:To realize a high-reliability demodulating operation by performing the generating processing of a function table in parallel with the demodulating operation and updating the function table used for the demodulating operation to a new table when this processing is completed and performing the maximum likelihood test on a basis of functional data matched to the latest noise state. CONSTITUTION:The output of a subtracting circuit 7 and demodulated data RD outputted from an output discriminating circuit 11 are read into a CPU12, and the CPU12 measures and analyzes a receiving noise state for a certain time on a basis of them. Simultaneously, a new function table matched to this noise state is generated in another function table memory 9b which is not used for the demodulating operation. When a series of analysis and measurement of the noise state and the generation processing of the function table are completed, the CPU12 switches bus switching circuits 8 and 10 simultaneously. Then, the function table memory 9b is connected to the subtracting circuit 7 and the output discriminating circuit 11, and hereafter, the maximum likelihood test is operated in accordance with the latest function table logP(Z) in the memory 9b, and the demodulated data RD is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) This invention (J. The definite V density function (p, d
, f), and use it as a parameter to determine the optimal reception of the synchronous system that achieves the transmittance ('I) on the receiving side alone.

(Revised version of the invention)) The optimum reception level using the subsequent method is constantly being checked in conjunction with the modeling of the target i′1[sound.

However, in either case, each vs. Z! A general-purpose optimal receiver that operates stably in any type of noise modeling exists only as a virtual receiver using a large computer. Ta.

For example, in order to realize Q-appropriate belief, first consider the modeling theory of noise, and then calculate the probability density function P(Z) of N sounds by
! I! Consideration has been given to developing a simplified formula that is easier to process and directly replacing the simplified formula with an electronic circuit, or to perform arithmetic processing of the simplified formula using a microprocessor.

In such a setup 1, if the nail model is clarified and a simplified formula is found, the optimal reception model corresponding to the simplified formula can be calculated, but these differ depending on the noise model. There are 8 types with very different calculation algorithms.In addition, in the case where the calculation of maximum likelihood test is performed using an analog circuit, the calculation processing speed (J is faster, or there are inevitably more 5 points of operation parameters) However, this method has the disadvantage that only a few people are added to the arithmetic expressions that can be applied to this method. Since it is possible to perform complex n μi operations without breaking the multilayer 1, there are not many restrictions on using the j quotient 1 mz ilHp formula.However, as the arithmetic algorithm becomes more complex, its processing speed is limited and large The drawback is that it can only support very low-speed data communication.

In any case, the optimal reception □ in the above-mentioned Jζ una system J1 method is only 7
rl works properly. Therefore, it is necessary to be extremely careful when inputting conditions such as is adopted, and the optimum is found under average conditions like children.

To put it the other way around, this can be said to be
If the states of different patterns are changed from <4, then the average state will be (J) and/or (J).

In order to achieve optimal reception that always operates optimally, it is necessary to have the ability to monitor the noise state of the communication line during operation, determine the l/Cδ1 condition, and apply the determination result to the maximum likelihood test. It is necessary to provide feedback as a parameter. However, in the past, this has not been proposed using a circuit that is actually easy to implement.

(Object 1 of the Invention) An object of the present invention is to perform maximum likelihood test calculation processing at high speed with a simple digital circuit that uses a large amount of memory, and
By measuring and analyzing the noise state during the receiving 3 operation and sequentially feeding back the results to the processing section, it is possible to always perform optimal reception by following the fluctuations in the f, 1I8- state of the 13th path. The object of the present invention is to provide a noise-following type synchronous general-purpose IQ appropriate reception system.

(Structure of the Invention) In order to achieve the above-mentioned objects, the present invention provides a method for achieving the noise probability density pl! IP(Z), its transformation or approximation function,
Alternatively, you can create the above function table using a function memory that stores part of the maximum likelihood test formula including these in the form of a daple, and digitized zamble values of the received signal waveform and synchronization signal waveform. Table 7? Based on the data retrieved from the access circuit and the function table memory, the maximum likelihood test is performed for each data transmission. Measure and analyze the noise state during reception based on the output judgment circuit, the above-mentioned table access circuit, and the output judgment circuit's motion frequency fl Q, and create a function table tailored to the noise state.2
The present invention is characterized by comprising a one-state analysis circuit and table updating means for placing the function table created by the analysis circuit in the function table.

(Backwards from the theory of invention)) In general, the probability-t-density function (1
1d, f) is given P(z)-4', then the same I'l
1 set of optimal reception ill CL, data 1 pin 1-11
Binary synchronization signals S+ (shi), Sko (+
It is well known that this can be achieved by combining 1 and 1τ (No. 11 χ(1) N times) and performing a maximum likelihood test using the operation expressed in equation (-1・1). There is.

Equation (1.1) shows that hypotheses 1 to l+ (S+ is sent and lζ) are selected when the value is small, and hypothesis H2 (Sz is sent) is selected when Δ or 1J is above. .

J, T, X 11 is the ηth sample of the received 16th wave, S11]・5211 is the ηth sample of the synchronization signal, In = S l n + Z n (I word is 5t) = S
The relationship is 2n+Zn (signal is 82). Here, Z n is 41, which represents miscellaneous goods.
is a rate variable.

By taking the logarithms of both sides of the above equation (1.1) and replacing them, the following equation (1.2) is obtained.

y−Σ(f!, ogP(χII −32n )1 −1agP (Xn −3+ n ) )50 −(1
・2)2 The optimum amount of this invention (g machine is the maximum likelihood test formula (1.2) above)
This operation is realized by the digital circuit described below.

(Description of the Embodiment) The figure shows the optimal reception (tM configuration) according to this explanation.The received signal χ(1> is routed from the signal applied to the input terminal IN by the filter 1 and the amplifier 2). Also,
From this received signal χ([), a synchronous extraction iJ1 circuit 3 extracts a clock OL indicating the transmission speed. The period of the synchronization clock CL is 1 bit l-0 of the IZ data; 'j is extremely old.

The received signal χ([) is subjected to −C rimbling and digitized by the A, , , −′ D conversion circuit 5,
The sample elevation Xn is input to the subtraction circuit 7.

The synchronous clock OL is applied to a synchronous timing circuit 4 consisting of a synchronized oscillation circuit, a synchronous frequency dividing counter, a decoder, etc. The timing line '1' of the waveform data memory 6, output determination circuit 11, etc. is set to '1'.

The synchronous timing circuit 4 is synchronized with the frequency 1 of the synchronous CL.
A signal with a frequency N times /'T is created and applied to the △/D conversion circuit 5 at the timing (No. 5). In other words, the received signal χ(1) is It is assembled N times.This multiple number is In(++=1.
2. ..., N).

The synchronous timing circuit 4 also generates a signal with a frequency of 2N/lower, and applies this signal with a frequency of 1/T to the output horn determination circuit 11 at the timing (a).

Further, the synchronous timing circuit 4 operates at R pins 1 to (21'-2).
The binary encoded output of N) is stepped at a speed of interval T/2 N, and one binary code is skipped every 1 data transmission time. This binary code output becomes the )7 do 1 NOS signal of the waveform memory 6.

The waveform method 6 contains data Sin and 5211 (n=
1.2. ..., N> are stored. However, data 3 IndS 2 n is stored in 2N addresses of memory 6.
is stored at intersection t7. That is, data S1[) is stored at an odd numbered address, and data 5211 is stored at an even numbered address -C. When the memory 6 is addressed by the binary output of the synchronization timing circuit 4, the synchronization signal waveform data S211, 3111 or n is read out and input to the subtraction circuit 7 manually.

The subtraction circuit 7 subtracts the output of the waveform memory 6 from the output of the Δ/'D conversion circuit 5 and performs a digital operation c? I'c? −
J now. In other words, data X1l-8211 and data χ11
Sin is outputted from the valve reduction circuit 7 to the AC I7, and this output is passed through the path switching circuit 8 to the output of either the function table 9a or 9b.

Function table memory 9a, 91+ address bus 1 rule switching circuit 8, data bus side switching circuit 1013. lCP
Controlled by U12. One C U12i. [, either one of the function table memories 9a and 9b is combined with the white, and the other one is reduced to 87 and output judgment times? Connects to 811.

Now, is it the function double memory 9a or the circuit? It is said that it is coupled to the seven-horn determination circuit 11. This 1-input memory 9a contains a function obtained by logarithmically transforming the probability function 1) (Z) of the eyebrow 1 sound of the communication channel as 1 object, as described below. ) is a function /'--sol D form δI2
It is remembered. In the initial state, the -7-ta of this function desol will be calculated in advance by another computer as J, but in the actual operating state, CI) U 12
This is a value created and modified by . J3, the function data here may be data of a function obtained by appropriately approximating or transforming j2ooP(Z).

When the function table memory 9a is addressed by the output of the circuit 7, the data AoaP (Xn-8zn)
The data RogP (Xn −9) n) is stored in memory 9.
are read out alternately from a. This data is input to the output determination circuit 11 via the bus switching circuit 10. The output determination circuit 11 receives the data sequentially read out from the function table memory 9a, and performs a total calculation of the equations (1 and 2) every l1iIT when transmitting one data of the received signal X(). Then, compare the gross autopsy result value y with 0, and find that y is o.
A signal indicating whether the value is smaller than or equal to 0, ie, I5 demodulated data RD, is output.

During the reception and demodulation operations described above, CPU i2 outputs the output of the attenuation circuit 7 (including the sample value χ of the received signal).
and the demodulated data RD output from the output η′ constant circuit 11h), and based on these, the noise state during reception is measured for a certain period of time l7-Sl.
Based on the analyzed and measured noise conditions, the function fusol memory 9LI that is not used for the demodulation operation is assigned a function corresponding to the noise conditions. Create a new table. For a series of one-tone ringing states (when h measurement and function daple creation processing are completed, the CI-'U 12 switches the bus switching circuits 8 and 10 to the same level) [this 1. LJ? I can do it now.

Then, the function daple memory 9b is connected to the reduction circuit 7 and the output judgment circuit 11, and the derivation of the maximum likelihood test is obtained by adding (Iη demodulated data R1] is created.CPU
124, at this time also the eyebrow 1 mentioned above? Isostate analysis measurement/function daple creation process JjP is used to update the function daple in step 9a used in the demodulation operation.

By repeating the above operation, the reception operation is performed according to the maximum likelihood constant σj by following the change in the status of the recipient (J) and always using an appropriate function table, thereby always achieving optimal reception υ. .

J3 function-1-pull and eogp(Xn-82n
) -Jl! It is also possible to use the function table of ogP (Xn - S + n) or its approximate function data, to draw this table by χ++, S211, S + n, and to accumulate the data. The data 32n and 511) may be simultaneously read out in parallel from the waveform data memory.

(Effects of the Invention) The main factor limiting the speed of the optimal reception (demodulation operation) of this invention is the operation speed of the memory used as a function double, and other accompanying simple 9fi J!I !
＋i仝C Can be executed with less than that distance. Therefore, it is possible to directly perform calculations between the key A and the real 111 at a high frequency level. Furthermore, it is only possible to make the transmission quality sufficiently high by giving the Iζth sampling number N of the maximum likelihood test.

Receiving the 41r%-density function of the 211 sound as an operating parameter (feeding it back to the circuit is to record the function data in the memory in the form of a table)
3, there is no need for external adjustment at all.(19)(shrug-(l) It operates at a constant rate.In addition, the measured noise state 11i/function de~
Tsuru's I'l-1 戊'4哩 can be easily converted to 1F using a -flu-like microprocessor, since it (J and speed is not required.) In tandem with the operation, the process of creating function 1-bull is performed, and when that process is completed, the function table used for the demodulation operation is updated to a new one. Then, quickly find the function f-ta that corresponds to the latest 211 effect state, perform a maximum likelihood test, and realize that the high 1 (period 1'1) of belief l!1ri1i is realized.

The optimum reception (interval timing) of this invention can be obtained at 4g, K, m (t
, l P SK (l Ino 11] Schiff 1 Heki Ink)
Then, 211 white F S l (frequency shift 1-
1 - Ink) - (Ats Cm, or (J derej to transform!,: Change 1i14 method τA-), and the same 1! Change the contents of 51
It can be used in a wide range of ways.

[Brief explanation of drawings]

FIG. 1 is a block diagram illustrating a (jl) rule for a noise-following type synchronous general-purpose optimum quantity 1z according to an embodiment of the present invention.

Claims (1)

[Claims] (1) Understand the probability function P(7) of the noise of the target and the delta path, and perform the maximum likelihood test using a systematic method based on the +3!] number P(Z). In order to obtain the demodulated data by performing optimal reception, ■ the probability density function vlp < z >, its modification or approximation function, or a part of the maximum likelihood test formula including these, of the number t [!] A function table memory stores data in the form of a table, and the received signal waveform d') Addresses the function table memory with digitized sample values of the received signal waveform d') and reads the corresponding function data. an output determination circuit that performs a maximum likelihood test determination for each data transmission based on the data read from the two-order function diple memory and obtains demodulated data; and the table access circuit and output. Is the notification being received based on the operation signal of the judgment circuit? Measure the A state (rr L, M sound state analysis circuit that creates a function table tailored to the noise state, and the M sound state analysis circuit created by this analysis circuit tt, IJII!). Havre history new means to increase by 1% etc. 7 [1 note) D subordinate form 1 and 1 set (1/L optimal quantity belief view).