TEA5764UK/N2,027 NXP Semiconductors, TEA5764UK/N2,027 Datasheet - Page 15

• Manufacturer Part Number: TEA5764UK/N2,027
• Description: Tuners FM RADIO WITH RDS
• Manufacturer: NXP Semiconductors

Specifications of TEA5764UK/N2,027

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 935278071027 TEA5764UK-G

Philips Semiconductors
TEA5764UK_2
Product data sheet
8.21.3 Auto high-side and low-side injection stop switch
8.21.4 Muting during search or preset
8.22 RDS update/alternative frequency jump
When a channel is searched or a preset is done, reception can sometimes improve when
injection is done at the other side of the wanted channel.
The TEA5764UK has bit HLSI which toggles the injection of the local oscillator from
high-side (bit HLSI = 1) to low-side (bit HLSI = 0). When bit HLSI is toggled, a new PLL
setting must be sent to the TEA5764UK.
When bit AHLSI is set to logic 1, the search / preset algorithm will stop after a channel has
a valid RSSI level check but fails the IF count. The microprocessor can now respond by
toggling the HLSI switch and sending a new PLL value to the tuner.
During a preset the tuner is always muted and this is implemented by the algorithm.
A search is not muted by default unless bit AFM = 1 or bit AHLSI = 1.
When bit AHLSI = 1 and the tuner stopped during a preset or a search because of a
wrong IF count, the tuner stays muted; this allows the microprocessor to switch from the
high to low setting quietly and wait for the new result.
The tuner is always muted if bit AFM = 1 and is independent of a search or a preset. A
search can be muted by setting bit AFM to logic 1 before a search is initiated and resetting
it to logic 0 when the tuner is ready (only set bit FRRMSK when initiating a search or
preset).
All these mute actions are done by blocking the audio signal inside the soft mute
attenuator, the audio output will keep its DC level and stay low-ohmic i.e. 50
mute set by bit MU will cause a plop).
A channel which transmits RDS data can have alternative channels which have the same
information. These alternative channel frequencies are in the RDS data, so the
microprocessor can read the alternative frequencies and store them in a memory.
The tuner can perform an RDS update. This is very similar to a preset, but with a 2 ms IF
count time. The tuner will jump to the alternative frequency and check the level and the IF
count using a 2 ms count time. When the RSSI level check is above the specified level and
the IF count result is within the limits, then the tuner will stay at the alternative frequency
and stay muted, the microprocessor can now decide what to do. If the alternative
frequency is not valid it will jump back to the frequency it came from.
Fig 4. Switch LO from high-side injection to low-side injection using bit HLSI
image on low-side
Rev. 02 — 9 August 2005
switch LO from high-side to low-side
wanted channel
image on high-side
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
TEA5764UK
001aab460
FM radio + RDS
(a hard
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