JPS62245730A - Duplex transmitter-receiver - Google Patents

Abstract

PURPOSE:To reduce number of multiplier circuits and local oscillators having a high frequency, to simplify and miniaturize the circuits by constituting the transmission section by a phase modulator, a local oscillator and a converter and providing a detector using an output of the local oscillator for direct detection to a reception section. CONSTITUTION:A transmission input such as telephone voice signal is modulated into an FM modulation signal at a low frequency being 100MHz or below with a modulator 5. The FM modulation signal is converted into the transmis sion FM modulation signal at a transmission up-converter 4 obtaining a signal of the transmission band while using a high frequency from an oscillator 2 of the fixed frequency and sent as a radio wave from an antenna 9 via a trans mission amplifier 6 and a branching filter 8. On the other hand, the reception signal received by an antenna 9 is fed to a quadrature mixer 1 via the branching filter 8 and a reception amplifier 7, subject to direct detection by using an output signal of the local oscillator 2 to obtain a reception output via a demodulator 3. Thus, the circuit constitution is simplified, number of multipliers and oscillators is decreased and the capacity of a battery or the like is made small and the transmitter-receiver is miniaturized.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a duplex transmitter/receiver, and more specifically, to a duplex transmitter/receiver that transmits and receives signals that are phase modulated (including FM modulation) in a frequency band of several hundred MHz IF. Concerning a duplex transceiver that processes simultaneously.

[Prior art]

Radio devices such as portable mobile telephones that are capable of simultaneously transmitting and receiving calls are being developed, but miniaturization of the device is extremely important for such radio devices.

As a conventionally known duplex transmitter/receiver used in a frequency band of 100 MHz or higher, the 100 MHz
The output signal of a local oscillator with a relatively low frequency of Hz or less is phase-modulated with a transmission signal, and this is frequency-multiplied to create a modulated transmission signal.The receiving section uses the signal obtained by multiplying the output of the local oscillator to generate a reception signal. Teterodyne detection of
”PotablaTelephones For C
e1lular System,” VTS 19
80°TORE), and the transmitter has a high frequency (1840°TORE).
MHz) oscillator is directly phase-modulated with the transmitted signal, and the receiving section performs heterodyne detection of the received signal using the output signal of a separately provided high frequency (840 MHz) oscillator (J. Ueda, Design Department). and Technology, Ho, FM Cellular Portable Telephone Equipment, J, UHDA.

“Design and Technology
for FMCellularPortable
Te1ephone Equipment"V
TS 1980゜Ion■) is known.

[Problem that the invention seeks to solve]

In these conventionally known transceivers, it is impossible to perform modulation using the output of a high frequency oscillator with current X technology, so multiple multipliers are required or high frequency requires multiple local oscillators.

This makes the device complicated, requires a large amount of power as a high-frequency power source, increases the size of the battery, and becomes an obstacle to downsizing the transmitter/receiver.

Therefore, an object of the present invention is to realize a simple and compact duplex transmitter/receiver by reducing the number of multiplier circuits and high frequency local oscillators.

[Means for Solving the Problems] In order to achieve the above object, the present invention uses a single local oscillator with a high frequency (for example, 800 MHz 8 degrees), and the transmitter uses a low frequency (for example, 45 MHz) local oscillator for the transmission signal. Hz
) to obtain an IF band phase modulated signal, and further perform the above step 1 using the output of the local oscillator described in
・Create a modulated transmission (i signal) by converting the frequency of the band phase modulation signal.

Further, in the receiving section, the output of the local oscillator is directly used to directly detect the received signal.

[Effect]

According to the present invention, a single local oscillator may be used, and the transmitter may be
A single frequency converter is sufficient, and since the receiving section performs direct detection and directly uses the output of the local oscillator, a frequency oscillator is not required. Therefore, the circuit configuration is simple, and a multiplier and an oscillator are required. Since the power consumption is reduced, the power consumption is also reduced, and therefore the battery etc. have a small capacity, and the size of the transmitter/receiver can be reduced.

〔Example〕

FIG. 1 is a block diagram showing the basic structure of an embodiment of a duplex transceiver according to the present invention.

In the figure, the transmission input of the 111th episode audio etc. is the modulator 5,
It is modulated into an FM modulation signal with a low frequency of 100 MH2 or less. The above FM modulation signal is converted into a signal in the transmission band by the transmission up converter 4, which converts the FM modulation signal into a transmission band signal by using a high frequency (several 100 MHy) of fixed frequency oscillation @2.
The signal is converted into a modulated signal and transmitted as a radio wave from the antenna 8 via a transmission amplifier 69 and a branching filter 8. On the other hand, antenna 9
The received signal (FM wave) received at
After passing through, it becomes the received output.

The quadrature mixer uses a circuit having a conventionally well-known configuration as shown in FIG. In Figure 2,
Terminal 7' has the output of the receiving amplifier shown in Figure 1, and terminal 2'
The output of the local excavator 2 is added to . The input from terminal 7' is divided, one is mixed directly with the output of local oscillator 2, and the other is mixed with a signal obtained by shifting the output of local oscillator 2 by 90'', and each is converted into a baseband signal by reduction filter 12. be done.

FIG. 3 is a more detailed circuit diagram of FIG. 1.

(Transmission section) The transmission signal output from the baseband circuit is
An FM modulated wave is generated by the FM modulator 5 operating in the 451 VIHz band. The FM modulated wave is further converted to a predetermined frequency by a transmission upconverter 4, passed through a transmission amplifier 6 and a duplexer 8, and radiated from an antenna. Frequency synthesizer 2 selects a transmission frequency.

(Receiving section) The minute radio wave input from the antenna is amplified by the reception amplifier, and the quadrature mixer directly detects the same local oscillation wave (output of frequency synthesizer 6) as the desired reception wave (here, the transmission and reception frequencies are is always 45 M
The principle of direct detection (assuming that the Hz is different) is
Two series of local oscillation waves having a phase difference of 90' from each other are prepared, and each is detected by a normal mixer. [, Q2 series baseband signal is obtained, I and Q are input waves with the local oscillation wave as a reference. corresponding to the vector representation component of
In the example of FIG. F''M demodulation, the phase of the input wave can be detected by performing the calculation 0=jan-'I/Q.

The de-M demodulated wave can be obtained by roughly differentiating θ with time. Note that in these operations, I and Q are Al1)
A suitable method is to convert the data, perform digital signal processing, or read out a ROM table.

Based on the above principles, it is possible to (J) use the local oscillator for both transmission and reception and (2) omit the receiving section TF band circuit.

〔Effect of the invention〕

(1) Effects of using one local oscillator (1) Reduction of high frequency parts. This effect, rather than power consumption, reduces the oscillator (usually a VCO), which is difficult to make monolithic because it includes a resonant circuit.

Great effect on circuit miniaturization.

i) If the transmitting and receiving stations have different frequencies, strict shielding is required to prevent mutual interference. As a result, the mounting efficiency decreases and miniaturization is hindered (both figures 1-a and 1-b solve this problem).

(2) Effect of direct detection The receiving section does not include IF amplification, resulting in lower power consumption (as shown in Figures 1-a and 1-b, the receiving section is equipped with a NiDO amplification stage)
6 The present invention requires an IYX band modulator in the transmitter as a compensation, but the disadvantage is slight due to the first-order reason. Reason: The normal use of a portable telephone is about 8 hours of standby (only the reception section is active) and 30 minutes of transmission. Since the standby time is overwhelmingly long (16 times) as described above, the receiving section power reduction 1 compensates for the transmitting section power width 16.

[Brief explanation of drawings]

FIGS. 1 and 3 are both block diagrams showing the structure of a duplex transmitter/receiver according to the present invention, and FIG. 2 is a diagram showing the configuration of a quadrature mixer used in the above embodiment. DESCRIPTION OF SYMBOLS 1... Quadrature mixer, 2... Frequency synthesizer, 3... Demodulator, 4... Transmission up converter, 5... FM modulator, 6... Transmission amplifier, 7...
Receive amplifier.

Claims (1)

[Claims] 1. In a duplex transmitter/receiver that performs simultaneous transmission and reception using two constant frequencies, a transmitter includes a phase modulator that modulates a transmission signal, a local oscillator, and an output of the phase modulator. a converter that converts the frequency of the modulated transmission signal using the output of the local oscillator, and the receiving section includes a detector that directly detects the received signal using the output of the local oscillator. Duplex transmitter/receiver. 2. The duplex transceiver according to item 1, wherein the received signal and the modulated transmission signal are phase modulated signals. 3. The duplex transmitter/receiver according to item 2, wherein the detector is constituted by a quadrature mixer.