JP3412661B2 - Data storage method for simultaneous transmission / reception wireless communication device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data storage method for time compression processing and time expansion processing of a simultaneous transmission / reception wireless communication device such as a cordless phone. 2. Description of the Related Art In a device of a simultaneous transmission / reception radio communication system such as a cordless phone, a local station and a partner station each have a transmitting section and a receiving section having equivalent functions, and the transmitting section of the local station transmits an audio signal. Time-division, time-compression processing of each of the divided audio signals is performed to convert the signals into intermittent signals, the carrier is modulated by the intermittent signals, converted into intermittent radio waves, and transmitted to the other station. The original audio signal is obtained by connecting the divided audio signals obtained by performing time expansion processing on each of the signals obtained by receiving and demodulating the radio waves in synchronization with the time division of the transmitting station. FIG. 4 shows an example of the configuration of a cordless phone using a spread spectrum communication system. On the transmitting side, an input voice input from a microphone 1 is amplified, passed through a level compression section 2 and time-compressed by a time compression section 3. Then, an intermittent signal is obtained, packetized by the packet assembling unit 4, pseudo-coded, modulated, and transmitted as airwaves in the air. On the receiving side, the received radio wave is demodulated and error correction is performed by the error correction unit 7, the packet is decomposed by the signal separation unit 8, and the output signal of the signal separation unit 8 is time-divided by the time expansion unit 9. The audio signal is expanded and time-expanded by the level expansion unit 10, and the divided audio signal is connected in synchronization with the time division of the transmitting station to obtain an original audio signal, amplify it, and output it as audio from the speaker 11. FIG. 5 is a block diagram showing an example of a conventional configuration of the time compression section 3 and the time expansion section 9 shown in FIG. 4. In transmission, the time compression section 3 outputs an output signal (audio signal) from the level compression section 2. ) Is converted from analog to digital by the A / D converter 31 and stored as a digital signal in the RAM 32, read out with a clock having a frequency of n (n ≧ 2) times the stored value, and converted to digital / analog by the D / A converter 33. Convert. As a result, 1 / n time compression is performed. The output of the D / A converter 33 is subjected to a frequency band limitation through an LPF (Low Pass Filter) 34 and then output to the packet unit 4. On the other hand, at the time of reception, the time expansion unit 9 converts the received signal (voice signal) decomposed from the packet by the signal separation unit 8.
Is converted from digital to analog by a D / A converter 91 and stored as a digital signal in a RAM 92, and is read out by a clock having a frequency 1 / n times that of the stored digital signal.
The converter 93 performs analog / digital conversion. As a result, the time is extended by n times. The output of the A / D converter 33 is subjected to frequency band limitation through the LPF 94 and then output to the level expansion unit 10. The RAM 32 of the time compression unit 3 and the RAM 92 of the time expansion unit 9
Is controlled by the timing controller 12. [0006] Normally, in a simultaneous transmission / reception radio communication device, a transmission voice signal and a reception voice signal are continuously input / output. Since one RAM is used for time extension processing at the time of reception, or two RAMs are required, there is a limitation in simplification of the circuit and miniaturization of the device. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned inconvenience, and focuses on the fact that data is only temporarily stored at the time of RAM (memory) time compression processing or time expansion processing. It is an object of the present invention to provide a digital data storage method for a simultaneous transmission / reception wireless communication device that enables time compression and time expansion operations with one RAM. [0008] In order to achieve the above object, a data storage method of a simultaneous transmission / reception wireless communication apparatus according to the present invention provides a simultaneous transmission / reception wireless communication apparatus that performs time compression processing during transmission and time expansion processing during reception. In the transmitting / receiving wireless communication device, the reference signal 1
A first timing signal having a frequency of 1/2 times, a second timing signal having a frequency which is 1 / n times the frequency of the first timing signal (n ≧ 2) and having a different phase from the first timing signal, and a second timing signal. The third with the same frequency and different phase as the timing signal
In the time compression processing at the time of transmission, time compression is performed using a third timing signal for writing data to the memory and a first timing signal for reading data from the memory, In the time extension process at the time of reception, time extension is performed using a first timing signal for writing data to the memory and a second timing signal for reading data from the memory. . DESCRIPTION OF THE PREFERRED EMBODIMENTS At the time of transmission, a third
Since the first timing signal having a frequency n times the frequency of the third timing signal is used for reading,
/ N time compression. On the other hand, at the time of reception, the first timing signal is used for writing to the memory and the second timing signal having a frequency of 1 / n of the first timing signal is used for reading, so that the time is expanded by n times. Further, since the first, second, and third timing signals have different timings, the readout to the RAM at the time of transmission and the reception,
The writing timing is different, and the memory area can be shared between transmission and reception. FIG. 1 is a block diagram showing an example of the configuration of an embodiment of a time compression unit and a time expansion unit to which a data storage method according to the present invention is applied, taking the cordless phone of FIG. 4 as an example. In FIG. 1, the time compression unit 3 and the time expansion unit 9 are RAMs.
13 during transmission, the time compression unit 3 converts the output signal (audio signal) from the level compression unit 2 from analog to digital by the A / D converter 31 and converts it into a digital signal into a timing signal X1CK (described later). RAM based
13 and read out with a timing signal X3CK (to be described later) three times faster than when this is stored, and D / A converter 33 performs digital / analog conversion. This gives 1 /
Time compression of 3 is performed. On the other hand, at the time of reception, the time expansion unit 9 converts the received signal (voice signal) decomposed from the packet by the signal separation unit 8.
Is converted from digital to analog by the D / A converter 91, stored as a digital signal in the RAM 13 based on the timing signal X3CK, and read out by a timing signal X1CK (described later) which is 1/3 times as fast as the stored signal.
A / D converter 93 performs analog / digital conversion. This results in a three-fold time extension. The timings X3CK, X1CK, and X1CK for the RAM 32 of the time compression unit 3 and the RAM 92 of the time expansion unit 9
Is the timing controller 1 as described below.
2 ′. In the cordless telephone of the embodiment, transmission and reception are switched by time division as shown in the timing chart of FIG. In FIG. 2, (a) is an input audio signal, (b) is transmission data, (c) is reception data,
(D) is a decompressed received audio signal, and (e) is a transmission /
“Rx” is processing on the receiving side, “Tx”
x ′ indicates the timing of the processing on the transmission side. As is clear from FIG. 2, since the transmission voice and the reception voice are continuously input / output to each other, the time compression processing at the time of transmission and the time expansion processing at the time of reception are shared by one RAM (one memory area). To do this, it is necessary to shift the timing of reading and writing to and from the RAM between transmission and reception. Therefore, as shown in the timing chart of FIG.
A timing signal X3CK having a frequency 1/2 the frequency of MCK with reference to K, a timing signal X1CK having a frequency 1/3 the frequency of X3CK, and a timing having the same frequency as X1CK but having a pulse pitch shifted by one pitch from X1CK. A signal X1CK is generated, and writing / reading of digital data to / from the RAM is controlled by these three timing signals. As is apparent from FIG. 3, the timing signal X1CK and the timing signal X1CK are shifted in phase (delayed by one pitch), and therefore do not overlap.
Further, the timing signal X1CK and the timing signal X1
Since CK and the timing signal X3CK have different phases, they do not overlap. Here, the reading / writing to / from the RAM 13 will be described. During transmission, the time compression unit 3 uses the timing signals X1CK and X1CK for writing to the RAM 13 among the three timing signals generated and transmitted by the timing controller 12 ′. X3CK is used for reading. Thus, since X3CK has three times the frequency of X1CK, 1/3 time compression is performed. On the other hand, at the time of reception, the time expansion unit 9 uses the timing signal X3CK for writing to the RAM 13 and the X1CK for reading out of the three timing signals. As a result, since the frequency of X1CK is 1/3 times that of X3CK, the time is extended three times. Also, X3CK,
Since the timings of X1CK and X1CK are different from each other, the timings of reading and writing to and from the RAM are different between the time of transmission and the time of reception.
AM (memory area) can be shared. In the embodiment, X3CK is 1/2 of MCK, X1CK, X1CK
1CK is set to a frequency which is 1/3 of X3CK, but is not limited to this. As described above, according to the present invention, the memory area for the time compression and time decompression processing can be shared, so that only one RAM is required. The size can be reduced. Further, the circuit configuration is simplified.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a configuration example of an embodiment of a time compression unit and a time expansion unit to which a data storage method according to the present invention is applied. FIG. 2 is a timing chart of time division of transmission / reception. FIG. 3 is a timing chart for generating a timing signal. FIG. 4 is a configuration example of a cordless phone using a spread spectrum communication method. FIG. 5 is a block diagram illustrating a configuration example of a time compression unit and a time expansion unit according to the related art. [Description of Signs] 3 Time compression section 9 Time expansion section 13 RAM (memory) MCK Reference signal X3CK First timing signal X1CK Second timing signal X1CK Third timing signal

Claims (1)

(57) [Claim 1] In a simultaneous transmission / reception wireless communication device that performs time compression processing during transmission and time expansion processing during reception,
(1) A first timing signal having a frequency half the frequency of the reference signal and a frequency (n
≧ 2), a second timing signal having a phase different from that of the first timing signal, and a third timing signal having the same frequency as the second timing signal and having a different phase,
(2) In the time compression processing at the time of transmission, time compression is performed using a third timing signal for writing data to the memory and a first timing signal for reading data from the memory. In the time expansion process, a first timing signal is used to write data to the memory.
A data storage method for a simultaneous transmission / reception wireless communication device, comprising performing time expansion using a second timing signal for reading data from the memory.