Feedback-Type Frequency Modulator

Takeshi HAYASAKA; Mitsuo NOGUCHI; Kenzo WADA; Kazuo SAKAMOTO

Feedback-Type Frequency Modulator

Takeshi HAYASAKA, Mitsuo NOGUCHI, Kenzo WADA, Kazuo SAKAMOTO

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A frequency modulator basically consists of an amplifier and a resonator employing a varactor diode, and the linearity of frequency modulators has been analyzed and discussed looking at the resonance frequency calculated from the capacitance-voltage characteristics of a varactor diode. However, as the oscillation frequency of the frequency modulator increases, it becomes essential for designer to evaluate the influences on the modulation linearity by the phase characteristics of the amplifier. This paper discusses the influences on the modulation linearity by the phase characteristics (the phase slope (or group delay) and the cross frequency f_c) and by the capacitance-voltage characteristics of varactor diodes, and the design of a UHF frequency modulator utilizing a hybrid integrated amplifier, is described. It is pointed out that, although the capacitance variation ratio n(log C(V)/log V) is less than 2, the capacitance variation ratio increases with the varactor diode bias voltage so that good modulation linearity can be obtained. Furthermore adopting a push-pull mode of operation, two UHF frequency modulators are connected to obtain a wideband frequency modulator (the bandwidth is f₀25 MHz). Finally a feedback-type frequency modulator operating at 6 GHz is discussed, as comparison to the result of the UHF frequency modulators.

Publication: IEICE TRANSACTIONS on transactions Vol.E63-E No.9 pp.647-654

Publication Date: 1980/09/25

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Type of Manuscript: PAPER

Category: Electronic Circuits

Authors

Takeshi HAYASAKA
Mitsuo NOGUCHI
Kenzo WADA
Kazuo SAKAMOTO

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Takeshi HAYASAKA, Mitsuo NOGUCHI, Kenzo WADA, Kazuo SAKAMOTO, "Feedback-Type Frequency Modulator" in IEICE TRANSACTIONS on transactions, vol. E63-E, no. 9, pp. 647-654, September 1980, doi: .
Abstract: A frequency modulator basically consists of an amplifier and a resonator employing a varactor diode, and the linearity of frequency modulators has been analyzed and discussed looking at the resonance frequency calculated from the capacitance-voltage characteristics of a varactor diode. However, as the oscillation frequency of the frequency modulator increases, it becomes essential for designer to evaluate the influences on the modulation linearity by the phase characteristics of the amplifier. This paper discusses the influences on the modulation linearity by the phase characteristics (the phase slope (or group delay) and the cross frequency f_c) and by the capacitance-voltage characteristics of varactor diodes, and the design of a UHF frequency modulator utilizing a hybrid integrated amplifier, is described. It is pointed out that, although the capacitance variation ratio n(log C(V)/log V) is less than 2, the capacitance variation ratio increases with the varactor diode bias voltage so that good modulation linearity can be obtained. Furthermore adopting a push-pull mode of operation, two UHF frequency modulators are connected to obtain a wideband frequency modulator (the bandwidth is f₀25 MHz). Finally a feedback-type frequency modulator operating at 6 GHz is discussed, as comparison to the result of the UHF frequency modulators.
URL: https://global.ieice.org/en_transactions/transactions/10.1587/e63-e_9_647/_p

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@ARTICLE{e63-e_9_647,
author={Takeshi HAYASAKA, Mitsuo NOGUCHI, Kenzo WADA, Kazuo SAKAMOTO, },
journal={IEICE TRANSACTIONS on transactions},
title={Feedback-Type Frequency Modulator},
year={1980},
volume={E63-E},
number={9},
pages={647-654},
abstract={A frequency modulator basically consists of an amplifier and a resonator employing a varactor diode, and the linearity of frequency modulators has been analyzed and discussed looking at the resonance frequency calculated from the capacitance-voltage characteristics of a varactor diode. However, as the oscillation frequency of the frequency modulator increases, it becomes essential for designer to evaluate the influences on the modulation linearity by the phase characteristics of the amplifier. This paper discusses the influences on the modulation linearity by the phase characteristics (the phase slope (or group delay) and the cross frequency f_c) and by the capacitance-voltage characteristics of varactor diodes, and the design of a UHF frequency modulator utilizing a hybrid integrated amplifier, is described. It is pointed out that, although the capacitance variation ratio n(log C(V)/log V) is less than 2, the capacitance variation ratio increases with the varactor diode bias voltage so that good modulation linearity can be obtained. Furthermore adopting a push-pull mode of operation, two UHF frequency modulators are connected to obtain a wideband frequency modulator (the bandwidth is f₀25 MHz). Finally a feedback-type frequency modulator operating at 6 GHz is discussed, as comparison to the result of the UHF frequency modulators.},
keywords={},
doi={},
ISSN={},
month={September},}

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TY - JOUR
TI - Feedback-Type Frequency Modulator
T2 - IEICE TRANSACTIONS on transactions
SP - 647
EP - 654
AU - Takeshi HAYASAKA
AU - Mitsuo NOGUCHI
AU - Kenzo WADA
AU - Kazuo SAKAMOTO
PY - 1980
DO -
JO - IEICE TRANSACTIONS on transactions
SN -
VL - E63-E
IS - 9
JA - IEICE TRANSACTIONS on transactions
Y1 - September 1980
AB - A frequency modulator basically consists of an amplifier and a resonator employing a varactor diode, and the linearity of frequency modulators has been analyzed and discussed looking at the resonance frequency calculated from the capacitance-voltage characteristics of a varactor diode. However, as the oscillation frequency of the frequency modulator increases, it becomes essential for designer to evaluate the influences on the modulation linearity by the phase characteristics of the amplifier. This paper discusses the influences on the modulation linearity by the phase characteristics (the phase slope (or group delay) and the cross frequency f_c) and by the capacitance-voltage characteristics of varactor diodes, and the design of a UHF frequency modulator utilizing a hybrid integrated amplifier, is described. It is pointed out that, although the capacitance variation ratio n(log C(V)/log V) is less than 2, the capacitance variation ratio increases with the varactor diode bias voltage so that good modulation linearity can be obtained. Furthermore adopting a push-pull mode of operation, two UHF frequency modulators are connected to obtain a wideband frequency modulator (the bandwidth is f₀25 MHz). Finally a feedback-type frequency modulator operating at 6 GHz is discussed, as comparison to the result of the UHF frequency modulators.
ER -