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From: Mauro Carvalho Chehab <mchehab@redhat.com>
To: unlisted-recipients:; (no To-header on input)@casper.infradead.org
Cc: Mauro Carvalho Chehab <mchehab@redhat.com>,
	Linux Media Mailing List <linux-media@vger.kernel.org>
Subject: [PATCH 10/11] [media] cx231xx: Improve signal reception for PV SBTVD
Date: Sun,  3 Mar 2013 12:58:50 -0300	[thread overview]
Message-ID: <1362326331-17541-11-git-send-email-mchehab@redhat.com> (raw)
In-Reply-To: <1362326331-17541-1-git-send-email-mchehab@redhat.com>

Instead of using 3.3 MHz IF, use 4MHz. That's the standard
value for the demod, and, while it can be adjusted, 3.3 MHz
is out of the recommended range. So, let's stick with the
default.
With regards to the IF voltage level, instead of using
0.5 V(p-p) for IF, use 2V, giving a 12dB gain.
The rationale is that, on PixelView SBTVD Hybrid,
even 2V(p-p) would be in the nominal range for IF,
as the maximum range on this particular device is 3V.
A higher gain here should help to improve reception under
weak signals.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
---
 drivers/media/usb/cx231xx/cx231xx-dvb.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/media/usb/cx231xx/cx231xx-dvb.c b/drivers/media/usb/cx231xx/cx231xx-dvb.c
index 7c4e360..14e2610 100644
--- a/drivers/media/usb/cx231xx/cx231xx-dvb.c
+++ b/drivers/media/usb/cx231xx/cx231xx-dvb.c
@@ -89,8 +89,8 @@ static struct tda18271_std_map cnxt_rde253s_tda18271_std_map = {
 };
 
 static struct tda18271_std_map mb86a20s_tda18271_config = {
-	.dvbt_6   = { .if_freq = 3300, .agc_mode = 3, .std = 4,
-		      .if_lvl = 7, .rfagc_top = 0x37, },
+	.dvbt_6   = { .if_freq = 4000, .agc_mode = 3, .std = 4,
+		      .if_lvl = 0, .rfagc_top = 0x37, },
 };
 
 static struct tda18271_config cnxt_rde253s_tunerconfig = {
-- 
1.8.1.4


  parent reply	other threads:[~2013-03-03 15:58 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-03 15:58 [PATCH 00/11] Do some improvements/fixups on mb86a20s, cx231xx and em28xx Mauro Carvalho Chehab
2013-03-03 15:58 ` [PATCH 01/11] [media] mb86a20s: don't pollute dmesg with debug messages Mauro Carvalho Chehab
2013-03-03 15:58 ` [PATCH 02/11] [media] mb86a20s: adjust IF based on what's set on the tuner Mauro Carvalho Chehab
2013-03-03 15:58 ` [PATCH 03/11] [media] mb86a20s: provide CNR stats before FE_HAS_SYNC Mauro Carvalho Chehab
2013-03-04 11:23   ` Mauro Carvalho Chehab
2013-03-03 15:58 ` [PATCH 04/11] [media] mb86a20s: Fix signal strength calculus Mauro Carvalho Chehab
2013-03-03 15:58 ` [PATCH 05/11] [media] mb86a20s: don't allow updating signal strength too fast Mauro Carvalho Chehab
2013-03-03 15:58 ` [PATCH 06/11] [media] mb86a20s: change AGC tuning parameters Mauro Carvalho Chehab
2013-03-03 15:58 ` [PATCH 07/11] [media] mb86a20s: Always reset the frontend with set_frontend Mauro Carvalho Chehab
2013-03-03 15:58 ` [PATCH 08/11] [media] mb86a20s: Don't reset strength with the other stats Mauro Carvalho Chehab
2013-03-03 15:58 ` [PATCH 09/11] [media] mb86a20s: cleanup the status at set_frontend() Mauro Carvalho Chehab
2013-03-03 15:58 ` Mauro Carvalho Chehab [this message]
2013-03-03 15:58 ` [PATCH 11/11] [media] em28xx-dvb: Don't put device in suspend mode at feed stop Mauro Carvalho Chehab

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