JPS6223927B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transmitting device in a high frequency (hereinafter referred to as RF) band such as a microwave band or a millimeter wave band.

In conventional wireless communication transmitting/receiving devices, delay equalizers have been used to compensate for delay characteristics generated in duplexers. FIG. 1 shows a transmitting section in this transmitting/receiving device. In the figure, 1 is a transmission frequency converter, 2 is a local oscillator, 3 is an RF amplifier, 4 is a duplexer, 5 is an antenna, and 6 is an intermediate frequency (hereinafter referred to as IF
) band delay equalizer. In the figure, all circuits having other functions are omitted for simplicity. Now, if the delay characteristics of the transmitting and receiving duplexers are small values, delay equalization can be performed all at once in the receiving section, but if the delay characteristics are large due to the narrow band of the duplexer, etc. Equalization becomes difficult, and equalization must be performed by dividing the signal into transmitters and receivers, and a delay equalizer is also required on the transmitter side.

Here, since the duplexer 4 is an RF band filter, it is a distributed constant circuit, but the delay equalizer 6 is an IF band filter, so it is a lumped constant circuit. Therefore, the materials of the constituent elements are different, and the two have different temperature coefficients. Even if the delay characteristics are compensated for at room temperature, when the surrounding environment such as temperature changes, the state of the delay characteristics changes significantly, and the delay cannot be compensated for. I can't get enough of it. Therefore, residual delay occurs, which has a significant negative impact on signal transmission.

FIG. 2 shows another transmitting section of a conventional transmitting/receiving device. In the figure, the duplexer 7 has not only the function of an RF band filter but also the function of a delay equalizer that compensates for the delay of the duplex filter. This delay equalizer is
Since it is an RF band circuit, it is a distributed constant circuit made of the same material as the filter and has the same temperature coefficient. Therefore, even if the surrounding environment changes, the duplexer and equalizer move in the same way, so the amount of residual delay is extremely small. However, in this configuration, since the delay equalizer is located on the output side of the RF amplifier 3, the passing loss not only becomes a loss for the output of the device, but also
It also has an adverse effect on signal transmission characteristics. For example, when performing digital transmission, compared to the embodiment shown in FIG.
Since the amount of back-off of the RF amplifier 3 decreases, the transmission characteristics also deteriorate.

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems and provide a high-frequency transmitter that stably compensates for delay characteristics even with changes in ambient temperature, etc., and has excellent signal transmission characteristics.

The present invention resides in a high frequency transmitting device characterized in that a delay equalizer for compensating for delay characteristics is provided between a frequency converter and a high frequency amplifier.

The present invention will be explained in detail below with reference to the drawings.

FIG. 3 is a block diagram of an embodiment of the invention. In this embodiment, the delay equalizer 8 that compensates for the delay of the duplexer 4 is connected to the transmission frequency converter 1 and the RF amplifier 3.
Since it is provided between the duplexer 4 and the duplexer 4, it is constructed of a distributed constant circuit like the duplexer 4, and the constituent elements are made of the same material and have the same temperature coefficient. Therefore, even if the surrounding environment changes, the delay characteristic compensation effect hardly deteriorates.

FIG. 4 is an input/output characteristic diagram regarding the transmitter according to the present invention and the conventional transmitter shown in FIG. 2, showing the relationship between the RF output and the input of the RF amplifier 3.

In the figure, 9 is the input/output characteristic according to the present invention;
10 shows the conventional input/output characteristics of FIG.
Now, assuming that the output level 11 is the RF output required by the device, the inputs of the RF amplifier 3 have input levels 12 and 13, respectively. As is clear from the figure, the input/output characteristics of the RF amplifier 3 are not necessarily linear, so in order to obtain the same RF output, it is necessary to
Even if the passing losses of the delay equalizers in FIG. 3 and FIG. Next, 14 and 15 indicate the amount of back-off of the RF amplifier 3 of each device. As is clear from the figure, the amount of back-off of the RF amplifier 3 in the transmitting/receiving device according to the present invention is much larger than that in the conventional one, so that the signal transmission characteristics are significantly improved in the case of digital transmission.

For simplicity, all circuits with other functions in the transmitting/receiving device have been omitted from the explanation, but for example, even if there is any other circuit between the frequency converter 1 and the RF amplifier 3, the delay equalizer It is clear that exactly the same effect can be obtained as long as is between the two. In addition, we have explained the case where the delay characteristics of a duplexer are caused by passing through a filter, but when multiple duplexers are connected to an antenna and each is affected by the delay of adjacent duplexers, A similar effect can be obtained when the delay is equalized. Furthermore, this explanation also applies when equalizing not only the delay caused by the duplexer but also delays caused by other parts of the device, or when only a part of the delay caused by the opposite duplexer is equalized. applies.

As explained above, the high frequency transmitting device according to the present invention does not deteriorate the characteristics due to fluctuations in ambient temperature when compensating for delay characteristics, requires low operating power, and has excellent signal transmission characteristics. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a transmitter of a conventional transmitter/receiver, FIG. 2 is a block diagram of another transmitter of a conventional transmitter/receiver, FIG. 3 is a block diagram of an embodiment of the present invention, and FIG. 4 is a transmitter/receiver. FIG. 3 is an input/output characteristic diagram of a high frequency amplifier used in the device. In the figure, 1... Transmission frequency converter, 2... Local oscillator,
3... High frequency amplifier, 4, 7... Duplexer, 5...
Antenna, 6, 8...Delay equalizer, 9, 10...
Input/output characteristics, 11...RF output level, 12, 1
3... input level, 14, 15... amount of back-off.

Claims (1)

[Claims] 1. A high frequency transmitting device characterized in that a delay equalizer for compensating for delay characteristics is provided between a frequency converter and a high frequency amplifier.