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authorBen Hilburn <ben@ettus.com>2011-10-25 15:34:05 -0700
committerJosh Blum <josh@joshknows.com>2011-10-26 10:23:57 -0700
commit72dd1bb03dd9812c6f9cbe44278f013d0685d0fa (patch)
treec57c057c4c2e5f57746e551166ff7917c166b83f
parentc463c42f343696c65d12fb1f4b5fafd5b9c59ab6 (diff)
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Adding stuff to the tune request docs.
-rw-r--r--host/docs/general.rst24
1 files changed, 15 insertions, 9 deletions
diff --git a/host/docs/general.rst b/host/docs/general.rst
index e1c93b13a..aa6ac7aa0 100644
--- a/host/docs/general.rst
+++ b/host/docs/general.rst
@@ -16,12 +16,19 @@ A USRP device has two stages of tuning:
* RF front-end: translates bewteen RF and IF
* DSP: translates between IF and baseband
-In a typical use-case, the user specifies an overall center frequency for the signal chain.
-The RF front-end will be tuned as close as possible to the center frequency,
-and the DSP will account for the error in tuning between target frequency and actual frequency.
-The user may also explicitly control both stages of tuning through the tune_request_t object.
-
-Pseudo-code for tuning the receive chain:
+In a typical use-case, the user specifies an overall center frequency for the
+signal chain. The RF front-end will be tuned as close as possible to the center
+frequency, and the DSP will account for the error in tuning between target
+frequency and actual frequency. The user may also explicitly control both
+stages of tuning through through the tune_request_t object, which allows for
+more advanced tuning.
+
+In general, Using UHD's advanced tuning is highly recommended as it makes it
+easy to move the DC component out of your band-of-interest. This can be done by
+passing your desired LO offset to the tune_request_t object, and letting UHD
+handle the rest.
+
+Tuning the receive chain:
::
//tuning to a desired center frequency
@@ -30,9 +37,8 @@ Pseudo-code for tuning the receive chain:
--OR--
//advanced tuning with tune_request_t
- uhd::tune_request_t tune_req;
- tune_req.target_freq = my_frequency_in_hz;
- //fill in tune request fields...
+ uhd::tune_request_t tune_req(my_frequency_in_hz, desired_lo_offset);
+ //fill in any additional/optional tune request fields...
usrp->set_rx_freq(tune_req);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^