JPH02253724A - Digital radio telephony equipment - Google Patents

Abstract

PURPOSE:To easily form an integrated circuit and to speedily converge a transient phenomenon when power supply is applied by generating the main part of a transmission frequency by using a multiplier circuit, for which the cascade connection of the multiplier circuit is executed in a multistage, and eliminating the necessity of a tank circuit for tuning to an output frequency. CONSTITUTION:When the oscillation frequency of a reference frequency oscillation circuit XO 35 is defined as f0 and the frequency division ratio of a fixed frequency divider circuit 36 is defined as M, the frequency of a frequency signal 91 is f0/M. For a multiplier circuit 37, the cascade connection of the well-known duplexing circuit is executed and the output frequency is f0.2<n> by the cascade connection in an n-number of the stages. The power supply is always applied to the XO 35, fixed frequency divider circuit 36, BA 33, VCO 34, variable frequency divider circuit 341 and phase comparator 342 and the transient phenomenon of the VCO 34 cause by switching transmission and reception can be avoided. This multiplier circuit 37 is composed of a pulse circuit and the transient phenomenon at the time of switching is speedily converged. Accordingly, after operation is switched to a transmission mode, the transmission can be immediately started.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a digital radio telephone device of a simultaneous transmission and reception system in which the radio frequencies for transmission and reception are the same.

[Prior Art] Conventionally, digital wireless telephone devices that allow simultaneous transmission and reception include devices that use separate radio waves for transmission and reception, and devices that use radio waves of the same frequency for transmission and reception by switching over time. There was.

In the case of a device that uses separate radio waves for transmitting and receiving, the allocation of radio waves becomes more difficult, and installing separate antennas for transmitting and receiving requires a large space, so normally one antenna is used for transmitting and receiving. However, this requires an antenna sharing circuit, and it is difficult to match different transmit and receive frequencies in one antenna, which may reduce the overall gain of the antenna.

In addition, in devices that use radio waves of the same frequency for transmission and reception by switching over time, it is possible to save power consumption by cutting off the power to unused parts of the transmitter when receiving the device. Simultaneous transmission and reception methods that use frequencies cannot achieve such power savings.

The present invention relates to a digital wireless telephone device with seven simultaneous transmitting and receiving methods using radio waves of the same frequency for transmitting and receiving, and these methods will be explained below.

Although FIG. 1 is a block diagram showing an embodiment of the present invention, except for the internal connections of the transmitting device (3) (not shown in FIG. 1), FIG. 1 is a block diagram showing a conventional device. Therefore, the conventional device will be explained using FIG. 1.

In Figure 1, (1) is an antenna, (2) is an antenna switching circuit, <3) is a transmitting device, (4) is a receiving device, and (5) is a digital signal modulation/demodulation circuit (hereinafter abbreviated as "MOD E M"). ), (6,) is a control circuit, (61) is a control W signal, (71), (72) are demodulated signals, (73) is a time expansion circuit, (74) is a decoding circuit, (75) is a Low frequency power amplifier, (8N,).

(82) is a modulation signal, (83) is a time compression circuit, (84)
) is an encoding circuit, 85) is a low frequency amplifier, (91) is a frequency signal, and (10a) and (1, Ob) are changeover switches.

The audio signal from the microphone is amplified by an amplifier circuit (<85), and then converted into a digital code by an encoding circuit (84).
The signal is cut every certain unit time (approximately 'D transmission/reception time) and time-compressed to approximately 1/2 by a time compression circuit (83) to become a modulated signal (82).

The modulated signal (82) is bit-synchronized in the MODEM (5), and a frame synchronization signal and a control-related signal to be sent (for example, an end signal 1 call signal) are added to become a modulated signal (81), which is sent to the transmitting device. <3) Modulate the transmitted radio wave (for example, frequency modulation).

The radio frequency signal input from the antenna switching circuit (2) to the receiving device (4) is amplified within the receiving device (4), demodulated, and then sent to the MODEM (5) as a demodulated signal (71).
Here, bit synchronization and frame synchronization are taken, the control related signals are input to the control circuit (6), and the digital code corresponding to the audio signal becomes a demodulated signal <72) and is input to the time expansion circuit (73). Ru.

The time expansion circuit (73) performs the opposite process to the time compression circuit (83), resulting in the original continuous digital code, which is converted into an analog audio signal by the decoding circuit (74).
The audio is amplified by the amplifier circuit (75) and output from the speaker.

The internal connections of the receiving device <4) are shown in FIG.
¥1 is the same in the conventional device.The conventional receiving device (4) will be explained with reference to FIG. In Figure 3, the same symbols as in Figure 1 indicate the same parts, (4, ('
) is a radio frequency amplifier circuit (hereinafter abbreviated as RFA), (
41) is the first mixing circuit (hereinafter the mixing circuit will be abbreviated as MIX), (42) is the VCOl (421> is the variable frequency divider circuit, <422) is the phase comparison circuit, (423) is the low-pass filter (hereinafter L (abbreviated as PF), (43) is a buffer amplifier circuit (abbreviated as FBA), (44) is a bandpass filter (hereinafter abbreviated as 31) F), (45)
) is the second mixing circuit, (451,) is the second local oscillation circuit (hereinafter the local oscillation circuit is abbreviated as LO), (46)
is BPF, (47) is an intermediate frequency amplifier circuit (hereinafter I
(abbreviated as FA), (48) is a limiter circuit, (49
) is a demodulation circuit.

If the frequency of the frequency signal (91) is f, 7M, then V
The output frequency of CO(42) is f, -87M.

However, B is the frequency division ratio of the variable frequency division circuit (421), and this value can be changed. The output frequency fo-B/M of V CO (42) becomes the first local oscillation frequency, and B A
(43) and is input to M I X (41). Mi
The output frequency of X(41) is the first intermediate frequency,
The transmission frequency is f such that the first intermediate frequency is a fixed frequency. /M unit, the first local oscillation frequency is also f. A variable frequency dividing circuit (421) is configured so as to be able to change the frequency in units of /M. BPF (44) The following circuits are well known in the art, so their explanation will be omitted.

Because radio waves of the same frequency are used, radio wave emission priorities and radio wave emission permission procedures have been established to prevent collisions even if radio waves are emitted from two or more locations at the same time.

For example, the signal transmitted by the "middle frequency" with the higher priority is demodulated and enters MODEM (5), and among these signals, the [start signal J and [end signal J] are controlled as control signals. If there is a request for the circuit (input to 6> to start one transmission of own station) or a command to start transmission from the "middle circuit", the signal will be constant after receiving a signal such as "end signal". After a period of time, a control signal (61) is output from the control circuit (6) to switch the changeover switches (1,0a), .

When switched to transmit mode, the transmitter (3)
Power is supplied to all circuits of
1) Fire away. Since a predetermined frequency is assigned as a transmission radio wave with a frequency separation of 87M,
In order to synthesize these transmitted radio waves, the transmitter (3) includes a crystal oscillator with frequency f, a frequency divider of 1/1M, and a PLL.
A VCO whose oscillation frequency is controlled by a VCO, a frequency multiplier circuit, etc. are included, and a portion of these circuits is supplied with power when switched to the transmission mode. Further, the conventional frequency multiplier circuit used in this type of transmitter 3) has a tank circuit tuned to the output frequency.

[Problem to be Solved by the Invention] Since the conventional device is configured as described above, the time required for the transient phenomena in the VCO and the transient phenomena in the multiplier circuit to converge at the time of switching from reception mode to transmission mode is shortened. Therefore, there is a problem in that a considerable amount of waiting time is required from the time when the transmission mode is switched to the time when transmission starts.

In other words, it takes time for the PLL to lock due to the effects of turning on the power or changes in the connected load, and it also takes time for the tank circuit used in the multiplier circuit to return to normal operation. This will result in

Furthermore, a multiplier circuit using a tank circuit requires large components such as a coil, which poses a problem in that it becomes an obstacle to miniaturizing the device.

The present invention has been made to solve this problem, and an object of the present invention is to provide a digital radio telephone device of a simultaneous transmitting and receiving system that can immediately transmit data when switched to a transmitting mode.

[Means for Solving the Problems] A digital radio telephone device of simultaneous transmission and reception according to the present invention is disclosed in Japanese Patent Application No. 6314 filed by the same applicant as the present applicant.
The main part of the transmission frequency is generated using a multiplier circuit in which multiplier circuits are cascaded in multiple stages, as disclosed in No. 0896 "Double Multiplier Circuit" (hereinafter referred to as a separate application).

In this invention, the main part of the transmission frequency is generated using a multiplier circuit in which multiplier circuits are connected in series, so that a tank circuit for tuning to the output frequency is not required. Since it does not require large components and can be configured with a pulse circuit, it is convenient for integrated circuits and allows for rapid convergence of transient phenomena when the power is turned on.

Embodiments] Examples of the present invention will be described below with reference to the drawings. 1st
The figure is a block diagram showing one embodiment of the present invention, and FIG. 3 is a block diagram showing the internal connections of the receiving device shown in FIG. omitted.

FIG. 2 is a block diagram showing the connections of the transmitting device of the present invention, in which the same reference numerals as in FIG.
32) is MIX, (33) is BA, (34) is VCO
5 (341,) is a variable frequency divider circuit, (342) is a phase comparator, (343) is an LPF, (35) is a reference frequency oscillation circuit (hereinafter abbreviated as XO), <36) is a fixed frequency divider circuit, (37) is a multiplier circuit, and (38) is a switch circuit.

The oscillation frequency of XO (,35) is set to fo, fixed frequency divider circuit (3
If the frequency division ratio of 6) is set to M, the frequency of the frequency signal (91) becomes fo/M. This frequency signal (91)
is sent to the receiving device (4>), and is also sent to the V CO (34).
) becomes the reference signal to control the Variable frequency divider circuit (341'
) is A, the output frequency of the V CO (34) is fo-A/M. Also, this frequency is the modulation signal〈
81).

The multiplier circuit (37) is a cascade of the circuits of the above-mentioned separate application, and the output frequency becomes f,-2'' due to n stages of cascade.Xo (35), fixed frequency divider circuit (36),

Power is always supplied to B A (33), V CO (34), variable frequency divider circuit (341), and phase comparator (342) to avoid transient phenomena in V CO (34) due to switching between transmission and reception. be able to.

The multiplier circuit (3
7), M I X (32), B P F (31
), P A (30) can save power consumption.

The control signal (61) controls the antenna switching circuit (2) to connect P A (30) to the antenna (1), and controls the switch circuit (38) to connect the output of the multiplier circuit (37) to MI.
This multiplier circuit (37) is composed of a pulse circuit as explained in a separate application.
Since the transient phenomenon at the time of switching is rapidly converged, transmission can be started immediately after switching to the transmission mode.

[Effects of the Invention] As described above, according to the present invention, by using the separately filed doubler circuit, the power supply is By eliminating "connections" and "disconnections", load changes are made so small that they have no effect, and the multiplier circuit is designed to be able to transmit immediately after switching to transmit mode, so different frequencies are used for transmitting and receiving. The overall antenna gain can be improved compared to the conventional antenna, and it has the effect of making it possible to reduce the size, price, and power consumption.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing connections of a transmitter in this invention,
FIG. 3 is a block 1z showing the receiving device of FIG. (1) is an antenna, (2) is an antenna switching circuit, (3) is a transmitter, (4) is a receiver, (5) is a MODEM, (
6) is the control circuit, (32) is the MIX, (34) is the VCO
l (341) is a variable frequency divider circuit, (342) is a phase comparator, (343) is an LPF, (35) is X05, (36) is a fixed frequency divider circuit, <37) is a multiplier circuit, (38) is a switch circuit, (61) is a control signal. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] Digital code of simultaneous transmitting and receiving method that transmits a digital code converted from an audio signal and a digital code representing a synchronization signal and a control-related signal, and controls a device via a control circuit using the control signal. In the wireless telephone device, an antenna switching circuit that temporally switches the same radio frequency for transmission and reception, and switches and connects the antenna common to transmission and reception to the transmitter or the receiver according to a signal from the control circuit; A reference frequency oscillation circuit that generates a reference frequency f_0 used in the transmitting device and the receiving device, is installed in the transmitting device, inputs the reference frequency f_0, and is controlled by a phase-locked loop to generate f_0・A/M (A is a variable positive A voltage controlled oscillation circuit (hereinafter abbreviated as VCO) that oscillates at a frequency of an integer (M is a fixed positive integer), a means for modulating the output of this VCO with a transmission signal, a means for modulating the output of this VCO with a transmission signal, A multiplier circuit that outputs a frequency of f_0.2^n (n is any positive integer) by a multiplier circuit that inputs an input and is connected with a doubler circuit, and is installed in a transmitting device and combines the output frequency of the VCO and the output of the multiplier circuit. a mixing circuit that generates a transmission frequency by mixing the frequency with the frequency, and a mixing circuit that is provided between the mixing circuit and the above-mentioned multiplication circuit, and connects an input signal for inputting the output of the multiplication circuit to the mixing circuit according to the signal from the above-mentioned control circuit. 1. A digital wireless telephone device capable of simultaneous transmission and reception, characterized by comprising: