JPH01174017A - Receiver - Google Patents

Abstract

PURPOSE:To receive plural channels simultaneously by one receiver by connecting blocks each consisting of a broad band high frequency amplifier and a complete synchronization homodyne broad band demodulator in cascade and extracting each demodulation signal from each connecting point and the final block through an LPF. CONSTITUTION:An inputted signal is amplified by a broad band high frequency amplifier 1 and inputted to an image elimination mixer 5 of the complete synchronization homodyne broad band demodulator 9. The phase and the frequency of a signal from a voltage controlled local oscillator 3 are oscillated while being matched with those of two signals desired to be received which have higher frequency. An undesired high frequency demodulation signal is inputted to a broad band high frequency amplified 2 of the next stage and its output is inputted to an image elimination mixer 6. Moreover, the oscillated frequency of the voltage controlled oscillator is set to f2-f1 and the phase is made coincident with that of a carrier (f2-f1). A output of an synchronization homodyne demodulator 10 is inputted to an LPF 8, where an undesired high frequency component is eliminated, resulting in obtaining a 2nd demodulation signal.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a receiving device capable of simultaneously receiving multiple channels.

2. Description of the Related Art Conventionally, in order to simultaneously receive multiple channels, it is necessary to have the same number of receiving devices as there are receiving channels, and there is no single receiving device that can receive multiple channels.

In the current TV receiver and video v2 installation cents,
An example of conventional technology is the ability to record a channel different from the one being watched on a television receiver.
The television receiver and the video device each have a receiving device7.
This makes it possible to receive two channels simultaneously.

Problems to be Solved by the Invention However, with the above configuration, when receiving multiple channels simultaneously, a receiving device is required for each channel, so the cost required for the receiving device is equal to the number of receiving channels. It had

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides a receiving device that is configured to be able to receive multiple channels simultaneously.

Means for Solving the Problems In order to solve the above problems, the reception Wi of the present invention connects blocks each consisting of a wideband high frequency amplifier and a fully synchronous homodyne wideband demodulator in 1α series, and connects each connection point to the final The block is configured to extract each demodulated signal from the block through a low-pass filter (hereinafter abbreviated as LPF).

The present invention has the above-described configuration, which enables simultaneous reception of multiple channels by a single receiving device having multiple demodulators, and at the same time, it is possible to simultaneously receive multiple channels using a homodyne detection method compared to the conventional heterogain detection method configured with a tuner and demodulator. By adopting the detection method, detection operation can be performed using only the demodulator, so it is possible to significantly reduce the number of parts and cost.

Embodiment Hereinafter, a receiving apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a block diagram of a receiving apparatus in a first embodiment of the present invention. In Figure 1, 1 and 2 are broadband high frequency amplifiers, 3 and 4 are voltage controlled oscillators, 5.6 is an image removal mixer, and 7.8 is an LP
F, 9.10 is a fully synchronous homodyne wideband demodulator, a is a high frequency signal input terminal, b, c are demodulated signal output terminals,
d is a modulated signal input terminal, e is a demodulated signal output terminal, and f is a local oscillation signal input terminal. Further, the image removal mixer 5.6 is configured as shown in FIG. 2, and 21.
22 is a 90° phase shift hybrid, 23 is an 0° phase shift divider, and 24.25 is a double balanced mixer (hereinafter referred to as DB).
(abbreviated as M).

(Quoted from the application examples in the R & ■ Quadrature Hybrid pamphlet).

The operation of the receiving apparatus configured as described above will be described below with reference to FIGS. 1, 5, 2, and 3.

Here, FIG. 3 illustrates an example of important frequency spectra in order to explain the operation of the block diagram in FIG. 1.
Figure 3 (al indicates the modulated high frequency signal input to the high frequency signal input terminal a, 31°33 is the carrier wave, 32.34
is the modulated signal.

3) is a frequency spectrum diagram of the demodulated signal output terminal e of the fully synchronous homodyne wideband demodulator 9, where 35 is the demodulated signal of the modulated signal 34, 36 is the carrier wave, and 37 is the modulated signal. 31 and the modulated signal 32 are frequency converted. Figure 3 +c+ is a frequency spectrum diagram of the demodulated signal output terminal e of the fully synchronous homodyne wideband demodulator 10, where 38 is the demodulated signal of the modulated signal 37, 39 is the demodulated signal, and the demodulated signal 35 is frequency-converted by the detection operation. It is something.

First, as shown in Fig. 3 ta+, among the many modulated high frequency signals that exist on the frequency axis, the carrier wave frequency is fl
Consider the case where two channels such as and fr (f2>L) are selected and received.

The signal shown in FIG. 3 tal inputted to the high frequency signal input terminal a is amplified by the wideband high frequency amplifier 1 and inputted to the modulated signal input terminal d of the image removal mixer 5 of the fully synchronous homodyne wideband demodulator 9. The voltage controlled local oscillator 3 oscillates the carrier wave 33 of the higher one of the three signals to be received with the same frequency and phase, and inputs it to the local oscillation No. 13 input terminal f to generate a fully synchronous wideband homodyne transverse wave. At this time, as shown in Figure 3 (bl), the demodulated signal output terminal e has the same circumference ei and number f vector with the origin at the position f2 on the wave number axis and the left direction as positive in Figure 3 (8). In addition, since the image removal mixer 5 is used, it is possible to prevent signals of channels with higher frequencies than f2 from being reflected back to the demodulated output in this detection operation and mixed with the required demodulated output. be able to.

The principle of this image frequency removal will be explained below. now,
The frequency of the carrier wave of the modulated wave to be demodulated is fp
(angular frequency ωR), fu and fl satisfy the following relational expression
Suppose that (angular frequency ω., ωI) is input to the modulated signal input terminal d together with fR.

fu ”'-fR-fn fr ”””(1
) In the 90° phase-shifted hybrid, these signals are divided into three signals phase-shifted by 0° and 90″, and the 0° phase-shifted components cosω, , t and cosω, t are DBM24
, the 90° phase shift components sinωut and sinω
, 1 are input to the DBM 25. In addition, since the signal input to the local oscillation signal input terminal f is completely synchronously detected, the frequency is fR and the phase also matches the carrier wave of the input modulated wave.
It becomes osωllt.

This signal is distributed by an O° phase shift divider 23 and DBM 24.
cosωR1 is added to 25. Therefore, DBM2
4.25, the following frequency components are obtained.

COSωut, cosω*t ='A (cos(ω, +ω++) t + cos
(ωt+-ω*)tl...(2) COSω, t, cosω and t = 'A (cos(ωt + 6)++) tlcos
(ωt −ωu) tl (3) sinωut, CO3ωIIt = A (sin(ω1+ωg) t + 5in(ω
, -ω1)tl... (4) sinω, t, cosω, 1 ='A (sin(ω1+ωm)tl5in(ω, -ω
1) tl...(5) That is, ω, ±ω3. Four frequency components of ω3±ω1 and their 90′ phase-shifted components appear, and their vector relationship is as shown in FIG. DBM from Figure 4
If the output of 08M25 is shifted by 90° and the output of 08M25 is phase shifted by 0° and synthesized by the hybrid 22 with a 90° phase shift, the image frequency component ω1-ω3 and the unnecessary frequency component ω8+ω are obtained.
0. It can be seen that ω2+ω does not appear at the demodulated signal output terminal e. For simplicity, it is assumed here that the phases of f, fu, and f input to the modulated signal input terminal d all match, but a similar result can be obtained even if the phases are shifted.

Unnecessary high frequency components are removed by L P F 7 from the demodulated signal obtained at the demodulated signal output terminal e as described above, and a demodulated signal 35 of the carrier wave 33 is obtained at the demodulated signal output terminal.

This wideband demodulated signal (FIG. 3(b)) is input to the next stage wideband high frequency amplifier 2, and its output is inputted to the modulated signal input terminal d of the image removal mixer 6.

Furthermore, the oscillation frequency of the voltage controlled oscillator is set to f2-f, and the carrier wave (f) of the signal input to the modulated signal input terminal d is
2 ++) and the local oscillation signal input terminal f.
Enter. As a result, the fully synchronous homodyne wideband demodulator 10 outputs a wideband demodulated signal as shown in FIG. 3 fcl to the terminal e. By inputting this output to LPF8 and removing unnecessary high frequency components, demodulated signal output terminal C
A demodulated signal 38 of the carrier wave 31 is obtained.

As described above, according to this embodiment, blocks each consisting of a wideband high-frequency amplifier and a fully synchronous homodyne wideband demodulator are connected in cascade in two stages, and the output of each demodulator is outputted through an LPF. This makes it possible to simultaneously receive two channels with -1 receivers.

Note that in the first embodiment, the number of connected blocks consisting of a wideband high-frequency amplifier and a fully synchronous homodyne wideband demodulator was set to two, but by further increasing the number of blocks, it is possible to simultaneously receive the same number of channels as the number of blocks. becomes.

Effects of the Invention As described above, the present invention cascades blocks consisting of a wideband high-frequency amplifier and a fully synchronous homodyne wideband demodulator; By providing the configuration of taking out the receiver, it is possible to simultaneously receive a plurality of channels with one or more receiving devices, and cost reduction can be achieved by simplifying the receiving device.

In particular, when simultaneous reception channels are close to each other, two
The frequencies handled by the blocks after the first stage are much lower than the frequencies handled by the first stage blocks, which makes the circuit configuration easier and can be integrated into ICs. It is advantageous in terms of cost compared to other methods.

[Brief explanation of the drawing]

FIG. 1 is a frequency spectrum diagram of demodulated signals of the receiving device and each demodulator in the first embodiment of the present invention, and FIG.
(dl is a vector diagram for explaining the operation of the image removal mixer. 1, 2... Broadband high frequency amplifier, 3.4...
...Voltage controlled oscillator, 5.6... Image removal mixer, 7.8... LPF, 9.10...
...Fully synchronous homodyne wideband demodulator, a...
...High frequency signal input terminal, b, c...Demodulated signal output terminal, d...Modulated signal input terminal, e
...Demodulated signal output terminal, f...Local oscillation signal input terminal. Name of agent: Patent attorney Toshio Nakao (1 person) Figure 2 24. Z5-7-Full Balance Domikibu Figure 3 O Sat fz f o fz-ft jo
fz-jt, jFigure 4

Claims (1)

[Claims] One block is a wideband high-frequency amplifier connected to a fully synchronous homodyne wideband demodulator consisting of an image rejection mixer and a voltage controlled oscillator, and multiple blocks are connected in cascade to generate a low-pass signal from each connection point and the final block. A receiving device characterized in that it is configured to extract each demodulated signal through a filter.