Audio System (If Equipped) - Mazda RX-7 1989 Owner's Manual

9 7 G3 0 510 t
AUDIO SYSTEM (if equipped)
A M / F M M ULT IP L EX R AD IO
D I VI I I I ; I I Y I IJNIN G
T lrc rc ; l po wcr a n te n n a rec etvoli lroll rAM
it rr r j I M : ; rt ; ra l s, w h ile th e w tndslttc ltl ;rrrlctt
n ir r oc or vos on l y F M b ro a dc asts Al l(,r r,rr;
r r ;r ll ; l r ir v e b e e n re c e ive d fro m brtl lr llrr' lt,t rl
irrrr i rcar antennas the antenna provtr lrttr I llrr r
Ir cst F M r e ce p tio n se l e cted. Thil; l; l.trowtr
as diversity tuning. With this rnetf ror I y,r t wtll
b e a ble t o e n j o y th e h ighes t tlrt;tl rly I M
reception.
NOTE
R e ar pow e r a n te n n a e le va t ion rs lrrlly ,rrrlo
m at i c Wit h t h e ig n i tio n sw itc h rtr ()ll (ll) rrr
A C C ( l) po s itio n , th e a n t enrut wtll ,' 1,' v ,rl,'
w h enev er t h e ra d io is t u rn c r i r rrr ; rrrr I wrll r, '
tr ac t w hen t he ra d io o r th tt t rl tttltott' ,wtlr lr t:,
turned off
lf the t ape is o p e ra te cl irfk rr ll rc rirri ro r', lrrrnc ri
o n , t he an t e n n a w rll st a y r ;rr;crl Wl rcrr llre
ta pe i s t ur ne d o l f, th c i rntc rtrr; r w rl l be
retracted
RAD IO REC E P TION
AM (Amplitude Modulation)
characteristics
AM signals bend arorrrrri :;rrr:l r l hi ngs as
buildings or mountau):,;rrrri lrorrrrce off the
ionosphere . Thereforc, l l rr ry r;li n reach
longer distances than I M r;rr 1r; rl :; Because
of this, two stati ons rn;ry :;orlctrmes be
picked up on the samc l rrrrl rrcl cy at the
same time
FM (Frequency Modulatlon)
characteristics
An FM broa dcast ra nge i s rr:;r rrl l y about
40-50 km (25-30 mi l es) frorrrtl rc source
Because of to extra coding ncct lcr I lo break
the sound into tw o channels, sl or(ro FM has
even leSS range than monaural (rronstereo)
FM Signals lrom an FM transmi tlor ri re si mr-
lar to beams of light because llrr:y do not
bend around corners, but they r1o reflect
Unlike AM signals, FM si gnal s car)not trav-
cl beyond the horizon. Therefore, t M sta-
trons cannot be received at the great
distances possible with AM receptton
Atmospheric conditions can also alk:ct FM
reception H i gh humi dity wil l causc poor
reception However, cloudy days m:ry pro.
vide better reception than clear days
Multipath Noase
Since FM signals can be reflected bv
structions, tt is possible to receive [:
the drrect signal and the reflected sic
at the same time This causes a sligh
lay In recef)lton and may be heard a
broken sorrnci or a distortion This or
lem may alr;o lrt-. encountered whe
close proxIr]rl v to the transm i t ter
Flutter/Skip Noise
Signals from llrc I M lransmitter mov
straight lines irr rr i lrccome weak in val
between tal l l rrrrl rl ngs, moun tai ns i
other obstacl c:; Wl ren a vehicl e pas
through such il n rrrca, th€ rece pti on c
ditions changc :;r rr lr lcnly, resulting in
noyrng notse
Weak Signal Noise
In suburban areal, lrroadcast signal
come weak becilr:;rlof distance from
transmitter Reccl rtrorr in such f ri
areas is charactcrrzc<i bv sound bre
up
Strong Signal Noise
This occurs very closc to a transm
tower The broadcast signals are
tremely strong, so the result is noise t
sound break-up at the radro receiv
3-36