JPH0237844A - Transmission output control circuit for broadband multichannel radio equipment - Google Patents

Abstract

PURPOSE:To minimize the dispersion of transmitting outputs between channels by providing a reference voltage generator to output a reference voltage corresponding to the frequencies of the plural channels. CONSTITUTION:Variable resistors R1-Rn and switches S1-Sn constitute a reference voltage generator 7A to selectively output an N number of reference voltages VR1-VRn and the variable resistors R1-Rn are adjusted beforehand in accordance with a coupling quantity to the frequency of a power detector 4. Consequently, even when a voltage signal changes by the difference of the frequency, the transmitting signal is controlled constant based on the reference voltage in accordance with the change of the voltage signal. Thus, the dispersion of the transmitting outputs between the channels can be minimized.

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a circuit for controlling the transmission output of a radio device that transmits wideband multi-channel signals to a constant level, and in particular to a circuit that controls the transmission output of a radio device that transmits wideband multi-channel signals to a constant level, and in particular, to The present invention relates to a transmission output control circuit for a wideband multi-channel wireless device capable of transmitting data.

[Prior Art] FIG. 2 is a block diagram showing a conventional transmission output control circuit for a wideband multi-channel radio device.

In the figure, (1) is a driver that variably amplifies the transmission signal A, and (2) is a power amplifier that amplifies the transmission signal A via the driver (1). (3) is a low-pass filter connected to the power amplifier (2) for removing harmonics higher than the second-order component included in the transmission signal A.

(4) is a power detector connected to the low-pass filter (3), which detects a high frequency (for example, 150 MHz) transmission signal A by M (coil) coupling or C (capacitor) coupling. (5) is the power detector (4
), (6) is a voltage regulator that includes a variable resistor to adjust the rectified voltage from rectifier (5), and (7) is a reference voltage generator that includes a variable resistor. (8) is the voltage signal VD from the voltage regulator (6)
and a comparator that compares the reference voltage VR from the reference voltage generation BS (7). (9) is a control unit that controls the amplification factor of the driver (1) based on the output signal H of the comparator (8).

(10) is a transmission output control section composed of (4) to (9), which is inserted between the low-pass filter (3) and the driver (1), and automatically controls the output of the transmission signal A. It is designed to be controlled at a constant level.

(11) is a low-pass filter that removes harmonics similarly to low-pass filter (3).
) and the transmission output control section (10). (12) is an antenna that outputs the transmission signal A via the low-pass filter (11).

Next, the operation of the conventional transmission output control circuit for wideband multi-channel radio equipment shown in FIG. 2 will be explained. Incidentally, in advance, coupling variations in the power detector (4) for each radio device are inputted by the voltage regulator (6), so that the voltage signal VD proportional to the transmission signal A is input to the comparator (8). It is also assumed that the reference voltage generator (7) is adjusted to generate a predetermined reference voltage VR.

Transmission signal A of the radio is amplified via a driver (1) and a power amplifier (2), and a low-pass filter (3).
And (11), high frequencies of two or more components are removed and transmitted from the antenna. At this time, the output of the transmission signal A is controlled to be constant by the transmission output control section (10) connected in a loop between the low-pass filter (3') and the driver (1).

That is, first, the power detector (
4) detects the transmission signal A through the low-pass filter (3) by M-coupling or C-coupling, and outputs a high frequency signal proportional to the output of the transmission signal A. The high frequency signal detected in this way is detected and rectified by a rectifier (5), and then becomes a voltage signal VD via a voltage regulator (6), which is output to a comparator (8).
) is entered.

The comparator (8) compares the voltage signal VD and the reference voltage VR, and inputs an output signal H representing the result to the control section (9). The control unit (9) determines the magnitude of the output of the transmission signal A based on the output signal H, and the voltage signal VD is determined to be the reference voltage V.
If it is smaller than R, increase the amplification factor of the driver (1) to increase the output of the transmission signal A, and conversely, if the voltage signal VD is larger than the reference voltage VR, reduce the increase rate of the driver (1). to reduce the output of the transmitted signal A.

In this way, control is performed until the voltage signal VD matches the reference voltage VR, and as a result, the output of the transmission signal A becomes constant.

In the above operation, the power detector (4) is M-coupled or C
A high frequency signal is detected by coupling, and the higher the frequency of the transmitted signal A, the greater the amount of coupling. Therefore, the voltage signal VD actually detected is not exactly proportional to the transmission signal A and varies depending on the frequency, and the output of the transmission signal A transmitted from the antenna (12) becomes smaller as the frequency becomes higher.

[Problems to be Solved by the Invention] As described above, the conventional transmission output control circuit for wideband multi-channel radio equipment controls the output of the transmission signal A based on one reference voltage VR. There was a point where variations in output occurred when switching to a channel with a different frequency.

This invention was made in order to solve the above-mentioned problems, and aims to provide a transmission output control circuit for a wideband multi-channel radio that can control the output of a transmission signal at a constant level even when switching to a different channel frequency. purpose.

[Means for Solving the Problems] A transmission output control circuit for a wideband multi-channel radio device according to the present invention is provided with a reference voltage generator that outputs a reference voltage corresponding to each frequency of a plurality of channels.

[Function] In this invention, the reference voltage is switched at the same time as the channel is cut off, and even if the coupling amount of the power detector changes due to a difference in frequency, the transmitted signal is switched based on the reference voltage according to the change in the voltage signal. is controlled to a constant value to reduce variations in transmission output between each channel.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure is a block diagram showing one embodiment of the present invention.
) ~ (6L (8), (9), (11) and (12) are the same as above. Also, (7^) and (10^) are the reference voltage generator (7) and the transmission output Each corresponds to the control section (10).

R1-Rn are N variable resistors provided corresponding to the number of channels, and each is connected in parallel to the comparator (8).

81 to Sn are N open/close switches connected to each of the variable resistors R1 to Rn, and only one of them is closed in conjunction with a channel cutoff switch (not shown).

The variable resistors R1 to Rn and the on/off switches S1 to Sn are
It constitutes a reference voltage generator (7^) that selectively outputs N reference voltages VR+ to VRn.

Next, the operation of the embodiment of the present invention shown in FIG. 1 will be explained.

Similarly to the above, the output of the transmission signal A is controlled by the transmission output control section (
10^) and transmitted from the antenna (12).

Here, when the channel of the transmission signal A is switched and the frequency changes, one of the open/close switches 81 to Sn is selectively closed in conjunction with the channel changeover switch.

For example, if channel i is selected, on-off switch Si is closed, and variable resistor Ri connected to it is closed.
becomes effective. Each of the variable resistors R1 to Rn is adjusted in advance according to the amount of coupling with respect to the frequency of the power detector (4), and is designed to generate a high reference voltage for a high frequency channel.

The reference voltage generator (7^) inputs the reference voltage VRi from the variable resistor Ri to the comparator (8), and the comparator (8)
Compare voltage signal VD with reference voltage VRi.

Therefore, even if channel i has a high frequency and a large voltage signal VD is detected, the reference voltage V
Since Ri also becomes high, the output of the transmission signal A is not controlled to be small. As a result, variations in the transmission output due to channel switching are corrected, and the transmission output is always constant regardless of the frequency.

Note that the relationship between the frequency of channel i and the reference voltage VRi is the same whether the power detector (4) is M-coupled or C-coupled.

[Effects of the Invention] As described above, according to the present invention, a reference voltage generator is provided that outputs a reference voltage corresponding to each frequency of a plurality of channels, and even if the voltage signal changes due to a difference in frequency, the voltage signal remains unchanged. Since the transmission signal is controlled to a constant level based on the reference voltage that corresponds to changes in effective.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing a conventional transmission output control circuit for wideband multi-channel radio equipment. (1)...Driver (4)...Power detector ()^)...Reference voltage generator (8)...Comparator (
9)...Control unit (10^)...Transmission output control unit A...Transmission signal VD...Voltage signal V R
i...Reference voltage H...Output signal S+zSn・
・・Opening/closing switch Figure 1 L + ---
” H: Manpower value number

Claims (1)

[Claims] A power detector for obtaining a voltage signal corresponding to the output of a transmission signal, a reference voltage generator for outputting a reference voltage corresponding to each frequency of a plurality of channels, and a comparison for comparing the voltage signal and the reference voltage. A transmission output control circuit for a wideband multi-channel radio device, comprising: a comparator; and a control section for controlling the output of the transmission signal to a constant level based on the output signal of the comparator.