A phase modulator ndi dera lomwe gawo la mafunde onyamula limayendetsedwa ndi siginecha yosinthira. Pali mitundu iwiri ya sine wave phase modulation: Direct phase modulation ndi indirect phase modulation. Mfundo ya kusintha kwachindunji kwa gawo ndi kugwiritsa ntchito chizindikiro chosinthira kuti chisinthe mwachindunji magawo a kuzungulira kwa resonant, kuti chizindikiro chonyamulira kudzera pamtundu wa resonant kupanga kusintha kwa gawo ndikupanga mawonekedwe osinthika; Njira yosalunjika gawo kusinthasintha koyamba modulates matalikidwe a yoweyula modulated, ndiyeno amasintha matalikidwe kusintha mu gawo kusintha, kuti tikwaniritse gawo kusinthasintha. Njirayi idapangidwa ndi Armstrong mu 1933, yotchedwa Armstrong modulation method
Makina oyendetsedwa ndi magetsi a microwave phase shifter ndi netiweki yamadoko awiri omwe amagwiritsidwa ntchito kuti apereke kusiyana pakati pa zotulutsa ndi zolowetsa zomwe zimatha kuyendetsedwa ndi siginecha yowongolera (nthawi zambiri ndi DC bias voltage). Kuchuluka kwa kusintha kwa gawo kumatha kusiyanasiyana mosalekeza ndi chizindikiro chowongolera kapena pamtengo wodziwikiratu. Amatchedwa ma analog phase shifters ndi digito phase shifters motsatana. The phase modulator ndi binary phase shift keying modulator mu microwave communication system, yomwe imagwiritsa ntchito mafunde opitilira muyeso kuti isinthe chizindikiro chonyamulira. Sine wave gawo modulation akhoza kugawidwa mwachindunji gawo modulation ndi indirect gawo modulation. Pogwiritsa ntchito ubale womwe sine wave amplitude Angle ndi wofunikira pafupipafupi, mafunde osinthika pafupipafupi amatha kusinthidwa kukhala gawo losinthika (kapena mosinthanitsa). Magawo omwe amagwiritsidwa ntchito kwambiri modulitsa gawo ndi varactor diode phase modulator. Dongosolo losinthira magawo osalunjika ndizovuta kwambiri kuposa gawo lowongolera molunjika. Mfundo yake ndi yakuti njira imodzi ya chizindikiro chonyamulira imasinthidwa ndi kusintha kwa gawo la 90 ° ndikulowa mu amplitude-modulator yoyenera kupondereza kusinthasintha kwa matalikidwe a chonyamuliracho. Pambuyo pa kuchepetsedwa koyenera, chizindikiro chomwe mwapeza chimawonjezedwa ku njira ina ya chonyamulira kuti itulutse chizindikiro cha matalikidwe-modulating. Derali limadziwika ndi kukhazikika kwafupipafupi, koma kusintha kwa gawo sikungakhale kwakukulu (nthawi zambiri kuchepera 15 °) kapena kupotoza kwakukulu. Ma module osavuta agawo amagwiritsidwa ntchito nthawi zambiri pama transmitters a FM.
