JPH0697850A - Wide band reception system in radio equipment and reception method - Google Patents

Abstract

PURPOSE:To reduce the oscillation frequency band of a voltage controlled oscillator to a value equal to a transmission/reception frequency band at the time when a first intermediate frequency is <=1/2 of the transmission/reception frequency band with respect to the system and the method for wide band reception of a radio equipment using the super-heterodyne system. CONSTITUTION:When the first intermediate frequency is <=1/2 of the transmission/reception frequency band in the wide band reception system of the radio equipment provided with an antenna 1, a first band filter 4 which filters the signal received by the antenna 1, a mixer 5, a controller 8, and a voltage controlled oscillator 9, the controller 8 decides whether the reception frequency is higher or lower than the frequency at the middle point of the transmission/reception frequency band and makes the local oscillation frequency lower than the reception frequency by the first intermediate frequency in the case of higher and makes the local oscillation frequency higher than the reception frequency by the first intermediate frequency in the case of lower and sets this local oscillation frequency to the voltage controlled oscillator 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wideband receiving system and a receiving method for a wireless device using a superheterodyne system.

[0002]

2. Description of the Related Art In a conventional radio apparatus, a voltage-controlled oscillator (VC) is used to widen the band of transmission and reception frequencies.
O) was trying to cover all the required band. In this case, the circuit becomes complicated and large, and it is difficult to downsize the device. In addition, there is a problem that covering all the bands with a VCO is very strict in satisfying the temperature characteristics. The present system and method are intended to remedy the above problems.

[0003]

Consider a case where a conventional radio apparatus has a double super-heterodyne receiving method and a local oscillation (local oscillation) frequency is lower. Assuming that the transmission / reception frequency band is Δf ₁ and the first intermediate frequency is Δf ₂ , the maximum value Δf of the transmission / reception frequency band (VCO transmission frequency band) required by the wireless device is Δf ₁ + Δf ₂ , and as shown in FIG. Become. As can be seen from FIG. 5, if the band Δf of the VCO unit is the transmission frequency band Δf _{1 as} it is, it is sufficient to secure a band of only Δf ₁ for widening the band. However, in the conventional radio receiver system, many devices using superheterodyne have to oscillate a local frequency and rely on the VCO for it. That is, when the VCO oscillation frequency band Delta] f of the received frequency F is near the lower limit of Δf ₁ Δf = Δf ₁ + Δf
₂ required. This system has a device frequency band = transmission / reception frequency band≈oscillation frequency band of the VCO unit, that is,
It is intended to compress the oscillation frequency band of the VCO unit to a band equivalent to the transmission / reception frequency (Δf≈Δf ₁ ).

Therefore, an object of the present invention is to reduce the oscillation frequency band of the VCO unit to a value equal to the transmission / reception frequency band when the first intermediate frequency is 1/2 or less of the transmission / reception frequency band.

[0005]

In the first mode of the present invention, an antenna 1 and a first band-pass filter 4 for filtering a signal received by the antenna 1 are exemplified as shown in FIG.
And a mixer 5 for receiving the output of the first bandpass filter 4.
A control device 8 for controlling the pass band of the first band-pass filter 4, a voltage-controlled oscillator 9 whose frequency is controlled by the control device 8 and which supplies its output to the mixer 5, and the mixer 5 The controller 8 comprises a second bandpass filter 6 for receiving a mixed output of the first bandpass filter 4 and the output of the voltage controlled oscillator 9 and sending it to the second mixer of the next stage. Frequency is 1/2 of transmission / reception frequency bandwidth
When it is below, it is determined whether the reception frequency is above or below the midpoint frequency of the transmission / reception frequency band, and if it is above, the local oscillation frequency is below the reception frequency by the first intermediate frequency, and below. If so, the voltage controlled oscillator 9 is set so that the local oscillation frequency is above the reception frequency by the first intermediate frequency, and the first band-pass filter is set so as to match the reception frequency. A broadband receiving system is provided.

In the second embodiment of the present invention, as illustrated in FIGS. 1 and 4, the antenna 1, the first bandpass filter 4, the mixer 5, the control device 8, and the voltage controlled oscillator 9 are used. A wideband reception method for a wireless device using a wideband reception system including: when the first intermediate frequency is less than or equal to 1/2 of a transmission / reception frequency band, the method includes the following processing steps, that is, the control device. 8 is a step of determining whether the reception frequency is the upper side or the lower side with reference to the frequency at the midpoint of the transmission / reception frequency band (S1). When the reception frequency is determined to be the upper side in the step, the control device 8 Sets the frequency of the voltage-controlled oscillator 9 below the reception frequency by the first intermediate frequency (S2), and when the reception frequency is determined to be below, the frequency of the voltage-controlled oscillator 9 is decreased. To the receiving frequency And a step (S3) of setting only the first intermediate frequency to the upper side, and a step (S5) of setting the pass band of the first band-pass filter 4 by the control device 8 corresponding to the reception frequency. A broadband receiving method for a device is provided.

[0007]

Using the present invention, as illustrated in FIG.
The first intermediate frequency Δf ₂ is the oscillation frequency band Δf of the VCO unit.
When it is set to ½ or less of the above, if the control device 8 sets the reception first local transmission frequency F ₂ to the upper side or the lower side as described above with respect to the reception frequency F, Δf _{1 of the} transmission / reception frequency band and VCO
The oscillation frequency band Δf of the unit 9 becomes equal, and the oscillation frequency band of the VCO unit falls within the transmission / reception frequency band.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A block diagram of a wideband receiving system for a wireless device of the present invention and a system for performing a wideband receiving method for a wireless device of the present invention is shown in FIGS. FIG. 2 shows the outline of the transmission / reception system, and FIG. 1 shows only the part related to the reception system.

This receiving system uses an antenna (ANT).
1, a bandpass filter (BPF1) 4 as a first bandpass filter, a mixer (MIX1) 5, a bandpass filter (BPF2) 6 as a second bandpass filter, a control device (CNT1) 8, a voltage controlled oscillator ( VCO 1) 9. In addition to this, as a transmission system, low-pass filter (LPF1) 2, antenna switch (ANT SW)
3, a power amplifier (PWAMP) 7, etc. are required.

The structure of the receiving system described above shows the conversion part to the first intermediate frequency of the double superheterodyne system, and the conversion part to the second intermediate frequency is omitted as the second mixer. In FIG. 1, the signal received by the antenna 1 passes through the bandpass filter 4, is mixed with the local oscillation signal from the VCO 9 in the mixer 5, and is converted into the first intermediate frequency. The VCO 9 can supply the frequency set by the controller 8. Further, the bandpass filter 4 can change the pass band under the control of the control device 8.

The process steps of the embodiment method will be described with reference to the flow chart of FIG. First, in step 1 (S1), the control device 8 determines whether the reception frequency F is above or below the frequency F _{1 at} the midpoint of the transmission / reception frequency band. If it is on the upper side (yes), the process proceeds to step 2 (S2), and the reception first local oscillation (local oscillation) frequency F ₂ is lowered by the first intermediate frequency Δf _{2 with} respect to the reception frequency, and the controller 8 controls the VCO 9
To set.

If it is the lower side (no), step 3 (S
Proceed to 3) and receive the first station frequency F ₂To the receiving frequency
Then, the first intermediate frequency Δf₂Control to set only above
The device 8 controls the VCO 9. In this way VCO9
PLL data is set (step 4 (S4)).
Next, the control device 8 controls the bandpass filter 4 to control the reception frequency.
Allow the band corresponding to the wave number F to pass (step
5 (S5)).

If the first intermediate frequency Δf ₂ is less than the oscillation frequency band Δf of the VCO section, the first reception frequency of the conventional reception
It can be set in a band narrower than the oscillation frequency band of the VCO unit in which the local oscillation frequency is fixed either above or below. In the embodiment, if the band of the band filter 4 is fixed, isolation or the like becomes a problem, but it can be solved by using the variable band filter so that the control device 8 controls the band filter 4.

[0014]

According to the present invention, when the first intermediate frequency is less than 1/2 of the transmission / reception frequency band, the oscillation frequency band of the VCO section can be reduced to a value equal to the transmission / reception frequency band. As a result, the circuit of the VCO unit can be simplified and downsized. In addition, the VCO section has excellent temperature characteristics and frequency characteristics, which makes it relatively easy to broaden the system bandwidth.

[Brief description of drawings]

FIG. 1 is a block diagram showing a wideband receiving system of a wireless device for explaining the present invention.

FIG. 2 is a block diagram of an example system.

FIG. 3 is an explanatory diagram comparing a transmission / reception frequency band and an oscillation frequency band of a VCO unit.

FIG. 4 is a flow diagram illustrating process steps for performing the method of an embodiment.

FIG. 5 is a diagram for explaining a transmission / reception frequency band and an oscillation frequency band of a VCO unit in a conventional example.

[Explanation of symbols]

 1 ... Antenna 2 ... Low-pass filter 3 ... Antenna switch 4 ... Band filter 5 ... Mixer 6 ... Band filter 7 ... Power amplifier 8 ... Controller 9 ... Voltage controlled oscillator

Claims (2)

[Claims] 1. An antenna (1) and a first bandpass filter (4) for filtering a signal received by the antenna (1),
A mixer (5) that receives the output of the first bandpass filter (4), a controller (8) that controls the pass band of the first bandpass filter (4), and a frequency by the controller (8). A voltage controlled oscillator (9) controlled and supplying its output to the mixer (5) and a mixture of the outputs of the first bandpass filter (4) and the voltage controlled oscillator (9) from the mixer (5). The control device (8) has a second bandpass filter (6) for receiving the output and transmitting it to the second mixer in the next stage, and the control unit (8) has a first intermediate frequency of ½ or less of the transmission / reception frequency bandwidth. At this time, it is determined whether the reception frequency is above or below the midpoint frequency of the transmission / reception frequency band. If it is above, the local oscillation frequency is below the reception frequency by the first intermediate frequency, and if it is below, it is local. Raise the oscillation frequency by the first intermediate frequency above the reception frequency A wideband reception system for a wireless device, wherein the voltage controlled oscillator (9) is set so that and the first bandpass filter is set to match the reception frequency. 2. A wideband receiving system comprising an antenna (1), a first bandpass filter (4), a mixer (5), a controller (8) and a voltage controlled oscillator (9). A wideband reception method for a wireless device, wherein when the first intermediate frequency is less than or equal to 1/2 of the transmission / reception frequency band, the method includes the following processing steps: A step (S1) of judging whether the reception frequency is the upper side or the lower side on the basis of the frequency of (1). When the reception frequency is judged to be the upper side in the step, the control device (8) causes the voltage controlled oscillator ( Setting the frequency of 9) to the lower side by the first intermediate frequency with respect to the received frequency (S2), when it is determined that the received frequency is lower, the frequency of the voltage controlled oscillator (9) is received. It is the first intermediate frequency with respect to the frequency A step (S3) of setting to the upper side, and a step (S5) of the control device (8) setting a pass band of the first band filter (4) corresponding to a reception frequency; Receiving method.