JPS6087507A - Transmission frequency converter - Google Patents

Abstract

PURPOSE:To attain miniaturization and low power consumption by providing a delay circuit, a multiplier and a narrow band-pass filter in a transmission frequency converter so as to generate inherently a local oscillation frequency. CONSTITUTION:An input signal (x) is inputted to the 2nd mixer 16 together with an output signal (z) via a delay circuit 15. The output signal (z) is normalizedby an output amplifier 13 and an ALC circuit 14 so that an average value of the amplitude of an output (s) of the band-pass filter is ''1'', and an output of the narrow band-pass filter 17 is a difference between the signals (x) and (z). In applying frequency conversion to the input signal (x) through the use of a local oscillation signal (y) at a mixer 11, the system acts like the transmission frequency converter.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new type of transmission frequency conversion device used in wireless communication systems.

Generally, in wireless communication, it is necessary to set the transmitting frequency and the receiving frequency to different frequencies within a range that prevents radio frequency interference and allows the antenna to be shared for transmitting and receiving. moreover.

In order to facilitate signal processing such as modulation/demodulation and band limiting, these are normally performed in an intermediate frequency band. For this purpose, a transmission frequency converter (up converter) is required on the transmitting side to step up the frequency from the intermediate frequency to the radio frequency.

As seen in the basic configuration diagram of FIG. 1, a conventional transmission frequency conversion device of this type includes a mixer (MIX), a 1° bandpass filter (BPF) 2, and an output amplifier (AMP) 3.

and a local oscillator (LOCAL O8C) 4. According to such a configuration, the two local oscillators 4 are economically expensive and have a large size, and the weight of the local oscillators in the entire device becomes very large.

Furthermore, since this local oscillator usually uses many active elements, it also has the disadvantage of increasing power consumption.

An object of the present invention is to provide a transmission frequency conversion device that is inexpensive, compact, and consumes little power by eliminating the above-mentioned conventional drawbacks and simplifying the two local oscillators.

According to the present invention, a first multiplier that receives an input signal and multiplies the input signal by a second input signal that is separately added;
a bandpass filter that selects only the frequency sum component from the output of the first multiplier, and an AL that receives the output of the bandpass filter;
an output amplifier that normalizes the average value of the amplitude of the output to a required value by control of a circuit such as C, a delay circuit that receives the input signal and delays the input signal, an output of the delay circuit, and the output. a second multiplier that receives the output of the amplifier and multiplies both; and a high-Q narrowband filter that selects only the frequency difference component from the output of the second multiplier; The output of the filter is applied to the first multiplier as the second input signal, and the output signal of the delay circuit and the output signal of the output amplifier are temporally connected at the input side of the second multiplier. There is obtained a transmission frequency conversion device characterized in that the delay of the delay circuit is adjusted to match .

Next, two embodiments of a transmission frequency conversion device according to the present invention will be described with reference to the drawings.

FIG. 2 is a block diagram showing the configuration of two embodiments of the present invention. In this figure.

11 indicates a mixer (MIX), which is used as a multiplier for the multiplier. 12 is a bandpass filter (BPF)
) and is used to pass only the sum term (sum frequency) from the multiplication result of the input signal and the local oscillation signal.

13 indicates an output amplifier, and 14 ALC (automatic
The level is automatically controlled by a (Level Control) circuit. 15 indicates a delay circuit.

Delay the input signal. 16 is the second mixer (MIX
), and the delay circuit 15 is set in advance so that the delayed signal from the given delay circuit 15 and the output signal fed back from the output amplifier 13 coincide in time. Note that the mixer 16 is used as a pass-gun multiplier that calculates the correlation between the input signal and the output signal.

Reference numeral 17 indicates a narrow band filter such as a resonator with a large θ, and serves to pass only a signal having a frequency that is the difference between the input signal and the output signal.

In such a configuration, now the input signal x'fcyx
= p a cos ('7J1 t 11.+α
) -= (1) a: average value of amplitude ω1: angular frequency θm of input signal, modulation phase term α: phase term, because the average value of output signal 2 is normalized to 1.

2−〆”!cos (ω2 is 1θ □ 1β) −= (2
) ω2. Angular frequency β of the output signal: expressed as a phase term. At this time, the output y of the narrowband filter 17 is.

y-difference term Cx'z)...(3) Totoru. However, the difference term [ ] means that only the term ω2−ω, (as ω2>ω1) is selected from among the signals expressed by the cosine in parentheses.

When formula (3) is specifically calculated.

y=-cOs ((ω2-ω1) is 10β-α) -==
(4) becomes. When the frequency of the input signal is converted using this local oscillation signal y, the output signal matches 2 of equation (2).

Then, this system (interphase roof °) will work as a transmission frequency converter. That is, in FIG. 2, it is assumed that the output S of the bandpass filter 12 selects only the sum term of the signals.

S-sum term CI”E a cos (ω1+θ, ten α)・
, -((ω2 ``1)t+β-α)]=y'l J-(
ω2 +−+β) ...(6). Since the output signal 2 is normalized by the ALC circuit 14 so that the average value of the amplitude is 1, the output signal 2 is 7'' in equation (6).

2-Mefcos (ω2 is 10θ. 10β) ・・・・・・(
7), which agrees with equation (2). Therefore, the second
The configuration shown in the figure operates as a transmission frequency conversion device.

As is clear from the above description, according to the present invention, a delay circuit 1 multiplier and a high-Q narrow band filter are provided in place of the conventional local oscillator to internally generate a local oscillation frequency. As a result, a compact, low power consumption, and economical transmission frequency conversion device can be obtained. In particular, a crystal filter or a crystal filter as a narrow band filter is used for a transmission frequency conversion device below UHF.
It is preferable to use a SAW filter, etc., and the effect of improving economic efficiency is significant.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of the configuration of a conventional transmission frequency conversion device, and FIG. 2 is a block diagram showing the configuration of an embodiment according to the present invention. In the figure, 11.16 is a mixer, 12 is a bandpass filter,
13 is an output amplifier, 14 is an ALC circuit, 15 is a delay circuit, and 17 is a narrow band filter.

Claims (1)

[Claims] 1. A second signal that receives an input signal and is added separately from the input signal.
a first multiplier that multiplies the input signal of the first multiplier; a bandpass filter that selects only the frequency sum component from the output of the first multiplier, and an AL that receives the output of the bandpass filter;
an output amplifier that normalizes the average value of the N-width of the output to a required value under the control of C or the like; and a delay circuit that receives the input signal and delays the input signal. a second multiplier that receives the output of the delay circuit and the output of the output amplifier and multiplies both; and a high-Q narrowband filter that selects only the frequency difference component from the output of the second multiplier. the output of the narrowband filter is applied to the first multiplier as the second input signal, and the output signal of the delay circuit and the output signal of the output amplifier are applied to the second multiplier. A transmission frequency conversion device characterized in that the delay circuit has a delay adjusted so as to coincide with each other in time on the input side of a multiplier.