JPS601946A - Two-way privacy call communicating method - Google Patents

Abstract

PURPOSE:To offer a privacy call circuit with simple circuit constitution by utilizing that the frequency of a voice signal passing through a storage circuit in response to the ratio of input and output clock frequencies in inputting or outputting the voice signal to/from the storage circuit while being sampled according to the clock. CONSTITUTION:A clock frequency at input/output is equal at all times by Equation III and a voice signal is reproduced without frequency distortion, since M+N clocks in total are received until a sound signal is outputted from a register 24 at a terminal B after the voice signal transmitted from a terminal A and received at the B is sampled in a register 3, in selecting a clock period J in a clock frequency ft from a clock generating circuit 4 to the relation of Equations I , II to bit numbers M, K, N, L of analog shift registers 3, 12, 24 and 31 and further in expressing ft as Equations IV, V. Since the clock frequency at input/output is not equal, however, other than Equation IV when the signal is transmitted from the terminal A, the frequency of the voice signal is changed in the ratio of f(ti+M)/f(ti) of the clock frequencies.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a wired or wireless two-way confidential communication method C:.

In wired or wireless communication, there is a possibility that the contents of the communication can be intercepted by anyone if an appropriate receiving device is used.

Therefore, the transmitted signal ζ2 undergoes special signal processing and is transmitted.
Even if this is intercepted, it seems that the contents cannot be understood, and there is a so-called secret story (8crem'b:Le
) circuit scheme is used as necessary.

Main) Prior Art As such confidential communication systems, frequency inversion systems, frequency division inversion systems, and the like are well known and widely used. However, these confidential communication systems have relatively complicated circuits and large frames, and are not suitable for mobile communications such as mobile phones and car phones that require portability. General radio communication is bidirectional communication, and each communication terminal has a transmitting system and a receiving system, and transmits and receives using two transmission channels. Therefore, it is usually necessary to provide two secret communication circuits for each communication terminal (two transmitting and receiving circuits), which further increases the overall scale of the apparatus.

(c) Objective and structure The present invention provides an apparatus capable of solving such problems. That is, the present invention samples an audio signal according to a clock and stores it in a memory circuit, or
When outputting audio according to the clock (2) If the clock frequencies of these input and output are not equal, the frequency of the audio signal passing through the storage circuit changes according to this ratio. The receiving circuit is provided with a storage circuit for the audio signal and a clock circuit for controlling the same, and these storage circuits at both ends of the communication system are synchronized and controlled periodically (two clocks) so that the transmitting side and the receiving side can be connected to each other for each transmission path. , complementary frequency conversion processing 31!jl is performed on the receiving side to simultaneously perform confidential communication processing on the transmitting and receiving transmission path, and it is a high-performance bidirectional confidential communication circuit with a relatively /JJ!J model and simple circuit configuration. The present invention will be described in detail below based on the drawings.

2) Example (2 drawings together with the apparatus of the present invention (11 mm in total).

Reference numeral 1N denotes a secret communication circuit for transmitting and receiving according to the present invention, and shows a communication terminal on the generation side of a synchronization signal, and FIG. 2 shows the same communication terminal (on the reception side of a synchronization signal).

Below, Figure 1 is for terminal +A+, and Figure 2 is for terminal IB+.
To call it (-.

(B) (=The audio signal to be transmitted is input circuit (1), LPF (2) temperature, storage capacity IM) (/) Analog shift register (3) Enter. The shift register (3) samples the clock (2), thus samples the audio signal, transfers it to vIllr4 and outputs it, and here BBD is used.This clock is given from the clock generation circuit (4). , this clock frequency f(tl (t is time) is the period (T
It is the periodic number of l. That is, fit) = = f (t + T) ... (1) The sampling data output from the storage circuit (3) from the Kubook flt mouth is sent to the output LPF (5), the adder circuit (6) described later, the amplifier, etc. Transmission circuit (Tran) including modulation circuit etc.
emtt, ter C1rcuit) (71, and is radiated into the air from the transmitting antenna (8).

In addition, the signal transmitted from the terminal (B) to the terminal prisoner and received by the receiving antenna (9)''-C is received and demodulated by the receiving circuit OI, which includes amplification, tuning, demodulation circuits, etc.
, the clock f+tl of the clock circuit (4)+the storage capacity It (Kl) which is controlled by the clock is inputted to the audio output circuit 04 including an amplifier, a speaker, etc. through an analog shift register (121) and an LPF (13).

On the other hand, 09 is a period information extraction circuit that extracts period information from the clock signal generated by the clock circuit (4), and this generates a synchronization signal generation circuit (Japanese). The period information extraction circuit (1!1) is, for example, if the clock f ltl has a period of J clock, 1111 is also J=ka f (t) at... (2) +T can be configured with a J-bit counter, etc., and a synchronization signal generation circuit (161) outputs a single sine wave 4M (for example, IDKHz 4F in-wave) outside the transmission audio signal band to the counter output (161). It can be constructed with a shadow-type circuit that modulates the amplitude by

The radio wave signal transmitted from IB+1- from the terminal prisoner is received by the receiving antenna Qυ shown in Fig. 2, and the baseband (; reprinted in No. 1, LPF )' The IM voice band signal passes through an N-bit analog shift register, an output LPF (c), and then an audio output circuit (2 to J (
Two people work together. On the other hand, the synchronization signal superimposed on the baseband signal is extracted by the synchronization separation circuit C20, and thereby the clock circuit (4) of the same clock frequency f as the terminal prisoner (the clock circuit Q0 that generates tl is the terminal tA). Synchronize.

Also, the audio signal sent from terminal (B) to January A) is
L P F from everyone's voice input circuit! 3 (via S, L-bit analog shift register [311g) is output from the LPF country, is modulated and amplified by the transmitting circuit (3, 1) including the variable UM and amplifier circuit, and is sent from the transmitting antenna Oa to the terminal. tAl, where the analog and log shift L/v stars I24) and 01) are transmitted to the clock circuit 12.
The clock is controlled by 81.

In the above configuration, the clock cycle (J) of the clock frequency (fit) is further changed to the analog shift register (3) by H%.
C2'n, (111) Each person number M, N, LI
JJ'LM+N;rnJ (m=1.2.3・) -T
10L in a2==nJ (n=1.2.3・) ・(4)
For any sampling time point (tl) by choosing the relation (2) f(ti)::f(ti+M+N)6f(ti+4−
L)...(5) and then f It) as f(ti)\f(ti+M)...(6) f(ti)
If we take 嶌f(ti+L)...(7), (however, ＼
is not always equal), in that case, the audio signal first transmitted from the terminal J1 and received at IBI is sampled into the analog shift register (3) and then transferred to the analog shift register of the terminal IB). (24
) until it is output! +' (M + N) clocks are received, so Equation (5) (2) These analog shift registers (2) have the same input/output clock frequency, so the audio signal is reproduced without frequency distortion.However, .

At the time when the analog shift register (3) is output and sent from the terminal IAI, the sampling clock f(tl)
However, the clock frequency f(ti+M) when clocked and output after M clocks is not equal as shown in equation (6)13, and the audio signal is the ratio of this clock frequency f(t
The frequency changes by i-)-M)/f(ti).

Similarly, the audio signal transmitted from the terminal IB) is sampled by the analog shift register (31) and is sampled by the analog shift register 0 on the receiving side (
(5) When outputting after the K+L) clock, the transmission signal is regenerated without any change in frequency because the clocks at the input, time, and output times are faster than those from the second clock.

On the other hand, at the stage when the analog shift register C311 is output and sent from the terminal (Bl), f(t
i+L)/f(tt).

As is well known (2. When the frequency of a signal changes, if the signal is a musical tone signal, the frequency is uniform (1 change only changes the pitch, but human When the frequency of an audio signal changes, it becomes unintelligible as speech depending on the degree of change.The reason is that most of the audio information is contained within its spectral structure.In reality, f(
ti+M)/f(ti) or f(ti+L)/f(
If ti) is about 1.5 or 0.7 on average, a sufficient secret effect can be obtained.

In addition, in FIG. 1 and FIG. 2, the analog shift register (LPF (2) (Iυ or r23CM)
% is necessary in order to remove the unavoidable aliasing noise in this kind of sampling circuit, and also the LPF (5) on the output side.
(13) and (c) are respectively required as audio band filters that remove high leg wave components contained in the output signal.

In addition, in the case of the present invention in which audio signals are discretized by sampling, the minimum value fm of the sampling frequency fTtl
A temporary variable function f(tl) is designed such that in is at least twice the transmission audio signal band and the sampling theorem is fiT.

As described above, the present invention provides the transmitting and receiving side of a wireless communication system (sound signal storage circuits for inputting and outputting audio signals according to the clock) in parallel, and controlling these with an apparently upward periodic clock. Since it is characterized by associating the clock cycle of the clock frequency with the number of clocks between input and output of the storage circuit, such a storage circuit may be an analog shift register such as a BBD, or a digitally encoded and stored audio signal. A shift register for transfer or a random access memory for storing and reproducing digitally encoded audio signals by specifying an address on the memory can be used.

Figure 6 shows the memory part when the analog shift register (BBD) part in Figures 1 and 2 is constructed with a digital shift register, and Figure 4 shows the memory part when it is constructed with a random access memory (RAM) as well. The memory part of the case is shown below. That is, in FIG. 3, ((1) is the clock circuit (apl)) (4) ((OF2) + 28 at terminal B
1) analog-to-digital converter that outputs the input audio signal in parallel as a B-bit digital record; are the outputs of these shift registers) Digitization of B bits -
digital-to-analog converters for converting F into analog values, each controlled by a clock circuit (4); With this configuration, the input terminal (1 m: the manually generated audio signal is clocked by the clock circuit (4),
Therefore, the analog-to-digital converter (40 bits) is transferred to the shift register (47 J (13...(14)) sequentially according to the clock as a B-bit digital code, and after the (45) AT is applied from the output terminal (1G) through Y. (The above configuration from 1 (1 to fll?I) can be replaced with (3) in Figure 1, and if M is set to 11 and L, then ( 121 or C41 (111) in FIG. 2 can be exchanged.

FIG. 4 is an example of a configuration consisting of RA and Ml2. In the figure, ■ is the audio input terminal, (51) is the clock circuit (4)
An analog-to-digital converter (52) that samples the audio signal and converts it into a digital code is controlled by the CMu analog-to-digital converter output memory address circuit (53), which is instructed by the Memory capacity for storing memory and rearaddress T-word RAM
, (54) is a digital/analog converter which converts the data at the address specified by the address circuit (5B) into analog data from the clock (2) and outputs it to the output terminal (55).Here, the memory address The circuit (53) is an M-bit counter that counts the falling timing of the clock output of the clock circuit (4), and the write/read clock is connected to the clock circuit (4) and an inverting circuit for the output of the clock circuit as shown in the figure. Readout using the output inverted by (56) as input? (Reading control circuit (R/
W circuit) (57) gives the difference 1, this (2) first from bAIA (52) to the address circuit (55) or ()j.
The data of 7 lines shown are read out by the clock of the inverting circuit (56), and then the output of the analog-to-digital converter (51) is read into the same address by the output clock of the clock circuit (4). As a result of this configuration, data sampled by the analog-to-digital converter (51) is stored in the RAM (52) and sequentially read out after M clocks. Therefore, this circuit using RAM is the first one and ? It is set at the same time as the analog shift register of f↓20, and is equivalent to L!
+: Can be exchanged. In addition, when the audio signal is sampled in this way, digitized in the analog-to-digital converter, and stored in °C storage ``4'', the transmission and reception of Jl and 2 systems in Figure 1 or No. 2N, respectively. By using a method of reciprocal sampling and processing, ); [A configuration of one set of an analog-to-digital converter, RAM, and digital-to-analog converter, the back voice converter for the two systems of transmitting and receiving is used. Numbers can be processed in parallel.

In the first and twentieth embodiments of the present invention, a synchronization signal for clock synchronization on the sending and receiving sides is sent from the terminal IAI (
Broni transmission 1 - transmission signal (- nails are folded, but synchronization 4
For No. 1 (using two independent transmission paths, or without sending the synchronization signal itself) - transmitting a reference signal with a known frequency, and transmitting it independently (by performing two-phase adjustment) on the receiving side so that it can be transmitted correctly. Any method is possible.

In this way, the circuit of the present invention has an audio signal Q) storage circuit provided in parallel, a periodic clock circuit that repeats at a clock cycle associated with the storage capacity of the circuit, and a transmitting/receiving side ( Synchronization of these clocks at two times 1''1f+Y(-) makes it possible to realize a bidirectional confidential speech processing circuit with a high degree of confidential communication effect using a comparative phloem h1 circuit configuration.

[Brief explanation of the drawing]

1 and 2 are prolag circuit diagrams for explaining the two-way confidential communication method of the present invention, and FIGS. 3 and 4 show the specific implementation of (i) and η1 of the present invention. 4-block circuit prisoner. (1) +21-...manpower, (2) (5) old 1 (13i (
C) (24 car threat...LPF, (3) (1 C (24) 0
1)...memory circuit, (4)...clock generation circuit,
(6)...Addition circuit, (7)1 H...Transmission (H circuit,
(81C (Furnace...Transmission antenna, (9) QD...Reception antenna, (111221...Reception [mouth 1 road, U,
萬(a...Voice power circuit, +15)...Same town information extraction II! i path, tte... synchronization signal generation circuit, (21
)...Synchronized minute 1! jl# circuit, +281...clock circuit.

Claims (1)

[Claims] (1) (al) At one end of the communication system, a transmitting side circuit station for transmitting the transmitting signal Z is provided, and the transmitting signal circuit 7 is provided (-therefore, it is sampled and stored;
: A storage capacity (Ml storage circuit and It)l which outputs the signal stored at one end of the communication system (=a receiving side circuit (=provided and The signal Y clock (2) is therefore sampled and stored (
(Ql) a clock circuit that clock-controls both of the storage circuits and whose clock frequency f (tl is a time period function), and (ldl) one end of the communication system. (1) Also provided is a synchronization circuit for synchronizing the output clock of the clock circuit, (θ1 communication system θ shoulder (!1) provided in the receiving side circuit for receiving the receiving signal at the 1 end, and a clock (2), a storage circuit of a storage capacity FitlpH for sampling and storing the signal and outputting the stored signal, and lf); the other end of the communication system; A side circuit C unit is provided with a storage circuit A1 which stores the transmission signal according to the clock (- storage capacity 1 old L) which outputs the stored signal, and Ig+.
) at the other end of the communication system (-), and the clock frequency is f' (tl (71 C7 circuit and th+) The memory circuits at both ends of the communication system are apparently the same. a synchronous circuit provided at the other end of the communication system for synchronizing both clock circuits, and an arbitrary synchronous circuit provided at the other end of the communication system for synchronizing both clock circuits. For sampling point (ti) (1: integer), f(ti) is expressed as f(tl+M+N) and f(t
i++L) then equal, and f(t1+M) and f
(ti+L) is a transmission system that converts the frequency of the transmission signal from each terminal by setting the time period such that 2 is not equal (2 transmission side and the reception side that received the transmitted transmission signal (2) Complement the frequency of the signal (convert it twice,
A secret communication method for both parties, characterized in that a signal with no frequency change is regenerated as a whole for transmission and reception.